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Home My WebLink AboutItem 3.4TOWN OF LOS ALTOS HILLS August 11, 2005 Staff Revert to the Planning Commission RE: CONDITIONAL DEVELOPMENT PERMIT FOR AN ADDITION AND REMODEL AND VARIANCES TO ALLOW TWO UNDERSIZED PARKING SPACES AND INCREASE OF MDA FROM 5,790 SQ. FT. TO 6,896 SQ. FT.; LANDS OF COHEN; 13303 WILDCREST DRIVE; #81-05-ZP-SD-GD-VAR- CDP. FROM: Debbie Pedro, AICP, Senior Planner -PIF. APPROVED BY: Cal Cahill, Planning Director C -C, - RECOMMENDATION: That the Planning Commission: Approve the requested Conditional Development Permit and Variance, subject to the recommended conditions and findings of approval in Attachments 1, 2, and 3. The subject property is a 1.817 acre parcel located on a steep south -facing hillside at the comer of Wildcrest and Robleda Drive. The property has an average slope of 47.2% and a LUF of 0.369. The site is developed with a 3,358 sq. ft. single -story home with an attached garage built in 1967. The existing home is situated on a cut and fill building pad with steep slopes to the north and south. According to the applicant's geotechnical report (Romig Engineers, Inc., 9/28/04), the southern portion of the house is located over a high crawlspace that was converted into a carport around 1988. Staff researched the Town's permit records and found that the previous owner had obtained a building permit for foundation repair in 1988 but no permit was found for the construction of the subject carport. The applicant is proposing an addition and remodel to the existing home, widening of the driveway and construction of a hammerhead fire truck turnaround on the property. As required by Section 10-1.1104 of the Zoning Code, this application for an addition and remodel has been forwarded to the Planning Commission for review and approval. A Conditional Development Permit is required any time a proposed project is located on a property with a Lot Unit Factor (LUF) of 0.50 or less. Pursuant to Section 10-1.1107(3) of the Zoning Ordinance, the Planning Commission, in reviewing a Conditional Development Permit application, determines whether the Staff Report to the Planning Commission Lands of Cohen 13303 Wildcrest Drive August 11, 2005 Page 2 of 12 proposed development meet the objectives and standards of the Town by considering evidence in support of four necessary findings. Findings for approval of the Conditional Development Permit is included for the Commission's review. (Attachments 2) In addition, the Zoning and Site Development sections of the Municipal Code are used to evaluate the proposal including building siting, floor and development area limitations, grading, drainage, height, setbacks, visibility, and puking requirements. DISCUSSION Site Data: Gross Lot Area: 1.817 acres Net Lot Area: 1.817 acres Average Slope: 47.2% Lot Unit Factor: 0.369 Floor Area and Development Area: Area (sq. ft.) Maximum Existing Proposed Increase Remaining Development 5,790 9,218' 6,896 -2,322 -1,106 Floor 3,690 3,358 3,570 212 120 'Development Area installed without permits by previous owner The applicant is requesting approval of a Conditional Development Permit for an addition and remodel to an existing house that will result in a net increase in 212 sq. ft. of floor area. The proposed improvements include converting an existing carport into a two -car garage, adding 244 sq. ft. of laundry and storage area behind the garage, adding 108 sq. ft. to the first floor kitchen, dining room and family room, remodeling the existing garage into a master bedroom, remodeling the interior space to reduce the ceiling height of the first floor, widening the existing driveway and constructing a hammerhead fire track turnaround. The addition and remodel is occurring entirely within the footprint of the existing building and should have minimal visual impacts to surrounding properties. The proposed building meets the setback, height, and floor area requirements established in Title 10, Zoning and Site Development, of the Los Altos Hills Municipal Code. The proposed development area exceeds the MDA and will require a variance. The maximum building height on a vertical plane and maximum overall height from the lowest to highest point is 30'. Pursuant to Section 10-1.504.a of the Municipal Code, the building is eligible for an increase in structure height subject to an increase in distance from the property lines. Staff Report to the Planning Commission Lands of Cohen 13303 Wildcrest Drive August 11, 2005 Page 3 of 12 Grading and Drainage Total proposed grading quantities include 200 cubic yards of cut and 50 cubic yards for the driveway. The Engineering Department has determined that approximately 120 square feet of grading exceed the Town's maximum allowable cut differential of 4' at the fire truck tum around area. Specifically, the steep slopes directly to the north of the driveway necessitate a slope cut of up to 8' at elevation contour 304 to accommodate the fire track turnaround. The grading policy allows the Planning Commission the discretion to approve grade differentials beyond standard requirements when the individual site dictates the need to deviate from the criteria. If the Planning Commission approves the project as proposed, the Engineering Department recommends conditions of approval which have been included in attachment #1. Pursuant to Section 10-2.503, Drainage Facilities Standards, of the Municipal Code, the Engineering Department has reviewed and determined that the proposed drainage design complies with Town requirements. Fire Department Review The Santa Clara County Fire Department is requiring the construction of a hammerhead fire truck turnaround and widening of the existing driveway to a standard 14'. (Condition #17) Due to the narrow lot and steep slopes, construction of the fire truck turnaround would require a retaining wall cut approximately 10' from the trunk of a 35" diameter valley oak. _... . Front 40' 52 Side 30' 39' Rear 30' 39' Grading and Drainage Total proposed grading quantities include 200 cubic yards of cut and 50 cubic yards for the driveway. The Engineering Department has determined that approximately 120 square feet of grading exceed the Town's maximum allowable cut differential of 4' at the fire truck tum around area. Specifically, the steep slopes directly to the north of the driveway necessitate a slope cut of up to 8' at elevation contour 304 to accommodate the fire track turnaround. The grading policy allows the Planning Commission the discretion to approve grade differentials beyond standard requirements when the individual site dictates the need to deviate from the criteria. If the Planning Commission approves the project as proposed, the Engineering Department recommends conditions of approval which have been included in attachment #1. Pursuant to Section 10-2.503, Drainage Facilities Standards, of the Municipal Code, the Engineering Department has reviewed and determined that the proposed drainage design complies with Town requirements. Fire Department Review The Santa Clara County Fire Department is requiring the construction of a hammerhead fire truck turnaround and widening of the existing driveway to a standard 14'. (Condition #17) Due to the narrow lot and steep slopes, construction of the fire truck turnaround would require a retaining wall cut approximately 10' from the trunk of a 35" diameter valley oak. Staff Report m the Planning Commission Lands of Cohen 13303 Wilderest Drive August 11, 2005 Page 4 of 12 The Town retained the services of arborist Michael Bench to determine whether the oak trees around the building site will be negatively impacted by the proposed construction. In his report dated May 26, 2005, the arborist evaluated the condition of the trees and stated that with proper protection and mitigation, the affected oaks would have a reasonably chance of survival (Attachment 6). To ensure the protection and preservation of the existing oak trees, staff is recommending the implementation of the tree protection plan provided in the arborist report. (Condition #2) Trees & Landscaping The site is heavily vegetated with oaks on the south side of the driveway along the creek and behind the house to the west. All trees on the property will be preserved except for two (2) 13" oak trees which will be removed to accommodate the widening of a substandard driveway required by the Fire Department. Staff is recommending the installation of two 15'11 x 8'W oak trees to mitigate the loss of the two heritage oaks. (Condition #4) Open Space Easement As a condition for site development, an Open Space Easement will be required over areas of oak woodland and where the slope of the land is 30% or greater. In addition, the area over the creek along the south property line and for 25' beyond the top of the creek bank will also be placed in an open space easement. (Condition #7) Open Space Easement Committee Review The Environmental Design Committee recommends protection of the existing oak trees around the property during construction. Staff Report to the Planning Commission Lands of Cohen 13303 Wildcrest Drive August 11, 2005 Page 5 of 12 Outdoor Li hg tine Twelve (12) exterior wall lights are proposed around the house. Staff has included condition #6 requiring the light fixtures to be down shielded, low wattage, and the covers on the fixtures be frosted or opaque so that the source of the lighting is not directly visible from off-site. Driveway and Parkin Access to the property is provided by an asphalt concrete driveway off of Wildcrest Drive at the eastern end of the lot. The applicant is required to improve the driveway to meet Fire Department standards by constructing a hammerhead fire truck turnaround and widening the existing driveway to 14'. Four (4) required parking spaces will be provided on the property outside the property line setbacks. The carport at the south end of the house will be converted to a two -car garage and two additional 10' x 20' outdoor parking spaces will be located in front of the main entrance. The new two -car garage has two undersized parking spaces (9' x 20') and will require a variance. Parking and Development Area Variances The applicant is requesting a variance to allow the conversion of an existing carport into two undersized (9' wide x 20' long) garage parking spaces. Per Section 10-1.601 of the Zoning Code, each residence shall provide four (4) parking spaces with dimensions of 10' x 20'. Because of the narrow shape of the lot and steep slopes south of the carport, there is limited area on the site to expand the carport into a full size garage without additional fill over the steep slopes downhill and substantial structural alterations to the building. Staff Report to the Planning Commission Lands of Cohen 13303 Wildcrest hive August 11, 2005 Page 6 of 12 The applicant is also requesting a variance to allow an increase of 1,106 sq. R. of development area over the MDA. The existing development area on the site exceeds the MDA by 3,428 square feet. This is partly because the previously owner appears to have installed decking and paving behind the home and in front of the carport without benefit of Town approval. The applicant is proposing to remove all non -permitted paving behind the house and restore the area to natural landscaping. However, even with the removal of all extraneous development areas, the total proposed development area still exceeds the MDA by 1,106 sq. ft. or 19%. This site is constrained by its shape and steep topography (47% average slope) which results in a LUF of 0.369. The low LUF restricts the maximum development area to 5,790 sq. ft. The steep slopes and long narrow shape of the lot necessitate the construction of a long driveway and onsite fire truck turnaround which covers approximately 2,600 square feet or 45% of the MDA, allowing for minimal remaining areas for decks, walkways, and patios. The applicant is requesting approval of the excessive development area because even though the proposed addition and remodel is occurring entirely within the existing footprint of the house and will be below the MFA, it is impossible to reduce the total development area below the MDA if a new fire truck turnaround is required to be constructed on the property. In order to approve the variance requests, the Planning Commission must find there are exceptional or extraordinary physical circumstances on the lot that create a practical hardship for the applicant to comply with the provisions of the Code. If the Commission decides to approve the variance request, findings for approval (Attachment 3) should be cited. If the Commission decides to deny the variance request, staff should be directed to prepare findings for denial and make the appropriate revisions to the conditions of approval. CEOA STATUS The project is categorically exempt under Class 1 of the State CEQA Guidelines 1. Recommended conditions of approval 2. Findings for approval of the Conditional Development Permit 3. Findings for approval of the Variance 4. Site Map 5. Worksheets #1 and #2 6. Recommendations from Arborist Michael L. Bench dated May 26, 2005 7. Recommendations from Santa Clam County Fire Department dated May 2, 2005 8. Recommendations from Cotton, Shires & Associates dated May 24, 2005 Staff Report to the Planning Commission Lands of Cohen 13303 Wildcrest Drive August 11, 2005 Page 7 of 12 9. Recommendations from Environmental Design Committee dated May 16, 2005 10. Development plans: site, topographic, grading & drainage, floor, elevation, section, roof, and lighting plans Staff Report to the Planning Commission Lands of Cohen 13303 Wildcrest Drive August 11, 2005 Page 8 of 12 ATTACHMENT RECOMMENDED CONDITIONS FOR A CONDITIONAL DEVELOPMENT PERMIT FOR AN ADDITION AND REMODEL LANDS OF COHEN, 13303 WILDCREST DRIVE File # 81-05-ZP-SD-GD-VAR-CDP PLANNING DEPARTMENT: I. No other modifications to the approved plans are allowed except as otherwise fust reviewed and approved by the Planning Director or the Planning Commission, depending on the scope of the changes. 2. Prior to beginning any grading operation, tree protection measures for the five (5) heritage oak trees around the driveway shall be implemented per the requirements of the tree protection plan prepared by arborist Michael L. Bench dated May 26, 2005. A certified arborist shall inspect the tree protection measures including fencing, irrigation, and mulching, and submit a letter to the Planning Department summarizing the findings of the inspection prior to issuance of the building permit The tree protection measures must be implemented throughout the course of construction. For further details on the tree protection requirements, please refer to the report from arborist Michael Bench dated May 26, 2005. 3. A certified arborist shall be present to inspect the grading/excavation activities around the 35" oak tree. A final letter from a certified arborist shall be submitted to the Planning Department summarizing the findings of the inspections and attesting to the health of the 35" oak tree prior to fmal inspection. 4. The two existing 13" oak trees shall be replaced with two (2) 48" box oak trees with minimum dimensions of 15'H x 8'W. The replacement trees shall be planted prior to final inspection. 5. Prior to requesting the foundation inspection, a registered civil engineer or licensed land surveyor shall certify in writing and state that "the location of the new residence and roof eaves are no less than 52' from the front property line and 39' from the side and rear property lines." The elevation of the new residence shall be similarly certified in writing to state that "the elevation of the new residence matches the elevation and location shown on the Site Development plan." The Staff Report to the Planning Commission Lands of Cohen 13303 Wildcrest Drive August 11, 2005 Page 9 of 12 applicant shall submit the stamped and signed letter(s) to the Planning Department prior to requesting a foundation inspection. 6. Prior to requesting the final framing inspection, a registered civil engineer or licensed land surveyor shall certify in writing and state that "the height of the new residence complies with the 30'-0" maximum structure height, measured as the vertical distance at any point from the bottom of the crawl space or basement ceiling if excavated below natural grade, to the highest part of the structure directly above (including roof materials)." The overall structure height shall be similarly certified in writing and state that "all points of the building (including chimneys and appurtenances) lie within a thirty-five (35 ) foot horizontal band based, measured from the lowest visible natural or finished grade topographical elevation of the structure along the building line and the highest topographical elevation of the roof of the structure." The applicant shall submit the stamped and signed letter(s) to the Planning Department prior to requesting a final framing inspection. The property owner shall grant an open space easement to the Town over areas of the property where the slope of the land is 30% or greater and over the creek along the south property line and for 25' beyond the top of the bank. The property owner shall provide legal description and plat exhibits that are prepared by a registered civil engineer or a licensed land surveyor and the Town shall prepare the grant document. The grant document, including the approved exhibits, shall be signed and notarized by the property owner and returned to the Town prior to submittal of plans for building plan check. Outdoor lighting is approved as shown on the approved plans. No lighting may be placed within setbacks except two entry or driveway lights. Lighting shall be down shielded, low wattage, shall not encroach or reflect on adjacent properties, and the source of the lighting shall not be visible from off the site. Any additional outdoor lighting shall be approved by the Planning Department prior to installation. Fire retardant roofing (Class A) is required for all new construction. 10. Skylights shall be designed and constructed to reduce emitted light (tinted or colored glass, or other material). No lighting may be placed within skylight wells. 11. No new fencing is approved. Any new fencing or gates shall require review and approval by the Planning Department prior to installation. Staff Report to the Planning Commission Lands of Cohen 13303 Wildcrest Drive August 11, 2005 Page 10 of 12 ENGINEERING DEPARTMENT: 12. As recommended by Cotton, Shires & Associates, Inc., in their report dated May 24, 2005, the applicant shall comply with the following: Supplemental Geotechnical Evaluations Inves62ation - The Project Geotechnical Consultant should review all geotechnical aspects of the current development plans and prepare recommended geotechnical design parameters for project retaining walls. A pier -supported retaining wall design should be considered along the southern side of the driveway. Additional subsurface exploration should be completed if deemed necessary. Consideration should be given to the potential merits of removing and replacing existing fill materials that may influence the performance of the driveway. The results of the supplemental evaluations should be summarized by the geotechnical consultant in a letter and submitted to the Town, for review by the Town Geotechnical Consultant, prior to acceptance of plans for building plan check b. Geotechnical Plan Review — The applicant's geotechnical consultant should review and approve all geotechnical aspects of the project building and grading plans (i.e., site preparation and grading, site drainage improvements and design parameters for foundations, retaining walls and driveway) to ensure that their recommendations have been properly incorporated. The results of the plan review should be summarized by the geotechnical consultant in a letter and submitted to the Town Engineer for review and approval prior to acceptance of plans for buildingplan check C. Geotechnical Field Inspection — The geotechnical consultant should inspect, test (as needed), and approve all geotechnical aspects of the project construction. The inspections should include, but not necessarily be limited to: site preparation and grading, site surface and subsurface drainage improvements, and excavations for foundations and retaining walls prior to the placement of steel and concrete. Staff Report to the Planning Conunission Lands of Cohen 13303 Wildcrest Drive August 11, 2005 Page 1 l of 12 The results of these inspections and the as -built conditions of the project should be described by the geotechnical consultant in a letter and submitted to the Town Engineer for review prior to final (as -built) project approval. For further details on the above geotechnical requirements, please refer to the letter from Cotton, Shires & Associates, Inc., dated May 24, 2005. 13. The site drainage associated with the proposed development must be designed as surface flow wherever possible to avoid concentration of the runoff. The proposed drainage shall be designed to maintain the existing flow patterns. Final drainage and grading shall be inspected by the Engineering Department and any deficiencies corrected to the satisfaction of the Engineering Department prior to final inspection. A final letter shall be submitted from the project engineer stating that the site grading and drainage were constructed in conformance with the approved plans prior to final inspection. 14. Any, and all, changes to the approved grading and drainage plan shall first be approved by the Town Engineering Department. No grading shall take place during the grading moratorium (November 1 to April 1) except with prior approval from the City Engineer. No grading shall take place within ten feet of any property line. 15. The location and elevation of the addition shall be certified in writing by a registered civil engineer or licensed land surveyor as being in/at the approved location and elevation shown on the approved Site Development plan prior to final inspection. 16. Two copies of an erosion and sediment control plan shall be submitted for review and approval by the Engineering Department prior to acceptance of plans for building plan check. The contractor and the property owner shall comply with all appropriate requirements of the Town's NPDES permit relative to grading and erosion/sediment control. All areas on the site that have the native soil disturbed shall be protected for erosion control during the rainy season and shall be replanted prior to final inspection. 17. The property owner shall inform the Town of any damage and shall repair any damage caused by the construction of the project to pathways, private driveways, and public and private roadways, prior to final inspection and release of occupancy permits and shall provide the Town with Staff Report to the Planning Commission Lands of Cohen 13303 Wildcrest Drive August 11, 2005 Page 12 of 12 photographs of the existing conditions of the roadways and pathways prior to acceptance ofplans for buildingplan check 18. Two copies of a grading and construction operation plan shall be submitted by the property owner for review and approval by the City Engineer and Planning Director prior to acceptance of plans for building plan check The grading/construction operation plan shall address truck traffic issues regarding dust, noise, and vehicular and pedestrian traffic safety on Wildcrest Drive and surrounding roadways; storage of construction materials; placement of sanitary facilities; parking for construction vehicles; and parking for construction personnel. A debris box (trash dumpster) shall be placed on site for collection of construction debris. Arrangements must be made with the Los Altos Garbage Company for the debris box, since they have a franchise with the Town and no other hauler is allowed within the Town limits. FIRE DEPARTMENT: 19. The applicant shall provide an access driveway and fire truck turnaround with a paved all weather surface, a minimum unobstructed width of 14', vertical clearance of 13'6", minimum circulating turning radius of 36' outside and 23' inside, and a maximum slope of 15%. CONDITION NUMBERS 7, 12a, 12b, 16, 17 AND IS SHALL BE COMPLETED AND SIGNED OFF BY THE PLANNING DIRECTOR AND THE CITY ENGINEER PRIOR TO ACCEPTANCE OF CONSTRUCTION PLANS FOR PLAN CHECK BY THE BUILDING DEPARTMENT. Project approval may be appealed if done so in writing within 23 days of the date of this notice. The building permit cannot be issued until the appeal period has lapsed. The applicant may submit construction plans to the Building Department after September 3, 2005, provided the applicant has completed all conditions of approval required prior to acceptance of plans for building plan check. Upon completion of the construction, a final inspection shall be required to be set with the Planning and Engineering Departments two weeks prior to final building inspection approval. NOTE: The Site Development permit is valid for one year from the approval date (until August 11, 2006). All required building permits must be obtained within that year and work on items not requiring a building permit shall be commenced within one year and completed within two years. ATTACHMENT 2 RECOMMENDED FINDINGS FOR APPROVAL OF A CONDITIONAL DEVELOPMENT PERMIT FOR AN ADDITION AND REMODEL LANDS OF COHEN, 13303 WILDCREST DRIVE File # 81-05-ZP-SD-GD-VAR-CDP The site jar the proposed development is adequate in size, shape and topography to accommodate the proposed intensity of development, including all structures, yards, open spaces, parking, landscaping, walls and fences and other such features as may be require by this chapter. The property is a sizable parcel (1.81 ac.) developed with a single story home. The proposed addition and interior remodel to add a master bedroom will result in a net addition of 212 sq. ft. of floor area which is below the MFA. The proposed improvements to the residence will meet the Town's required setbacks, floor area, building height limits and site topography. However, due to the addition of a required hammerhead fire truck turnaround, the total development area exceeds the MDA and will require a variance. 2. The size and design of the proposed structures create a proper balance, unity and harmonious appearance in relation to the size, shape and topography of the site and in relation to the surrounding neighborhood The proposed addition is modest in size with no expansion to the existing building footprint. In addition, the house is screened by dense vegetation that will be placed in an Open Space Easement surrounding the site with little or no visual impacts to other properties in the neighborhood. 3. The rural character of the site has been preserved as much as feasible by minimizing vegetation and tree removal, excessive and unsightly grading and alteration of natural land forms. The addition and remodel of the home will occur entirely within the footprint of the existing building to minimize excessive grading around the building site. All existing trees and vegetation will be preserved except for the removal of two heritage oaks to accommodate the widening of a substandard driveway. 4. The proposed development is in compliance with all regulations and polices set forth in the Site Development Ordinance. The proposed improvements to the home meet the setback, height, and floor area requirements established in the Town's Zoning and Site Development Code. However, due to the required addition of a hammerhead fire truck turnaround, the total development area exceeds the MDA and will require a variance. ATTACHMENT RECOMMENDED FINDINGS FOR APPROVAL OF VARIANCES TO ALLOW TWO UNDERSIZED PARKING SPACES AND INCREASE OF MDA FROM 5,790 SO. FT. TO 6,896 SO. FT LANDS OF COHEN, 13303 WILDCREST DRIVE File # 81-05-ZP-SD-GD-VAR-CDP Because of exceptional and extraordinary circumstances applicable to the subject property, including size, shape, topography, location or surroundings, the strict application of the provisions of this Title is found to deprive such property of privileges enjoyed by other properties in the vicinity and under identical zoning classification. Because of the steep topography and narrow shape of the lot, there is very limited building area on the site to expand the existing carport into a full size garage without additional fill over the steep slopes downhill and substantial structural alterations to the building. In addition, the location of the existing home requires a long driveway and the construction of an onsite fire truck turnaround which will consume over 45% of the MDA. This poses a unique development constraint to the property because the property is already subject to a reduced MDA because of the low LUF. It is impossible to reduce the total development area below the MDA if a new fire truck turnaround is required to be constructed on the property. 2. Upon the granting of the variance, the intent and purpose of the applicable sections of the Zoning Ordinance will still be served and the recipient of the variance will not be granted special privileges not enjoyed by other surrounding property owners. Granting of the variance would not provide the owners of the property with any special privileges or allow installation of improvements that are not enjoyed by other residents in the area. The undersized parking spaces in the garage can accommodate parking for two vehicles. Along with the two surface parking spaces on the site, it will provide for four (4) off-street parking spaces on the property as required by the Municipal Code. The variance for additional development area will allow the applicant to install a driveway and turnaround as required by the Fire Department. Even though the total proposed area will exceed the current MDA, there will be an overall reduction of existing development area on the site. Staff Report to the Planning Commission Lands of Cohen 13303 Wildcrest Drive August 11, 2005 Page 2 of 2 The granting of such variance will not be materially detrimental to the public welfare or injurious to the property, hnprovenena or uses within the immediate vicinity and within the sane zoning district The addition and remodel to the home will result in a building that is consistent with the residential character of the neighborhood. In addition, the property is screened by dense shrubs and trees and will have no impact to neighboring properties in the immediate vicinity or within the same residential zoning district. 4. The variance will not authorize a use or activity which is not otherwise expressly authorized by the Zoning District regulations governing the parcel ofpropeny. The project is an addition and remodel to a single family home which is an authorized use in the R -A zoning district and would be compatible with existing land uses in the surrounding areas. D IL L 4 IL a MO' M (7 W 016 � y N C N Up O co H co a c J ATTACHMENT y x WW ix N ry __ _ -r`-'-ieSi —� O z y fi te d' 3 iF x48 i '� ATTACHMENT y x WW ix N ATTACHMENT y iF x48 i '� / J p vwmoe try Qa ATTACHMENT y Fpr 21 05 09:29a GIULIANI KULL 409 615 4004 p.l ATTACHMENT 5 TOWN OF LOS ALTOS HILLS 26379 Fmuaoat Roat • Los Altos Hills, California 94022 • (650) 941 722 • FAX (650) 941-3 t60 DECEIVED PLANNING DEPARTMENT WORKSHEET #1 APR 2 2 2005 CAba—LATION OF AVERAGE SLOPE, LOT U!VIT FACTOR TOWN OF LOS ALTOS HILLS 1,1AXAILTIM DEVELOPMENT AREA, AND MAXIMUM FLOOR AREA 1. CALCULATION OF AVERAGE SLOP A. CONTOUR LENGTH WITHIN NET AREA OF LOT (An) Concert inches w f= (multiply by map scale) = (L) = 7T �� feet B. AVERAGE SLOPE WITHLN NET AREA OF LOT (L) An = pot acreag<of T- contour interval FL = total length of An Al feet 'L_contonr5 in feet jl I__ lot nearest ,001 S = _ (0.00231 ( �5 ) (745a) _ ( I.911 ) arest O. I% 2. CALCULATION OF LOT UNIT FA TOR 'L TFl LUF = (An)j1 - [0.02143(S - 10)]) = r _; ; nearest .001 If the average slope is less than 10%, the LUF for the lot is equal to the net area. ----�1 If [he LUF is equal to or less than 0.50, you will need a ConditionalDevelopment Permit Make an appointment with the Planning Director for further information. ra, I iaoi Page 1 of 2 -OWN OF LOS ALTOS HILI - 26379 Fremont Road • Los Altos Hills,ualiforni9 4022 TY 65 ) 941-7222 • FAX (650) 9�1i7 E MEN" WORKSHEET #2 APR 2 2 2005 EXISTING AND PROPOSED DEVELOPMENT AREA AND FLOOMOS ALTOS HILLS • TURN IN WrrH YOUR APPLICATION PROPERTY OWNER'S NAME ./. s1+ Oe—UW, a,144 A — PROPERTY ADDRESS)'jjJjplj I CALCULATED BY �]pFt �t2.'j'Dra DATE 401+1 �q ,pti 1. DEVELOPMENT AREA (SQUAREFOOTAGE) A. House and Garage (from Pan 2. A.) B. Decking C. Driveway and Parking (Messaed i ov along mntaline) D. Patios and Walkways E. Tennis Court F. Pool and Decking G. Accessory Buildings (8om Pmt B) H. Any other coverage TOTALS Existing Proposed Total (Additions/Deletiow) 'ji'hri °0 212.2 �iGi'f o , 2 ✓ 2h3�i C/o M°'Zi 1 �0'k �i ^ I�DJd 2ND O p o O G O d 0 O p p O O5 "t Maximum Development Area Allowed - MDA (from Worksheet #1) 2. TOTAL IMPERVIOUS SURFACE Existing Proposed Total (SQUARE FOOTAGE) TOTALS �Oe)I — I&e?15 2;?5tp 3. FLOOR AREA (SQUARE FOOTAGE) Existing Proposed (Addifims/Deletions) A. House and Garage a. 1st Floor c>.v,dw, laoadr�r S_1_ e b. 2nd Floor ��lot3dt,K;+ck->7.R„�,, 2231 c. Attic and Basement A.an ww d. Garage "ei Gill l B. Accessory Buildings a. I st Floor O b. 2nd Floor c. Attic and Basement O TOTALS e Maximum Floor Area Allowed - MFA (from Worksheet #1) MX1.2 Lo��f ,ti Total 'fJ°j5. Gi ✓ D D D p 2122 3�io.,2./✓ TOWN USE ONLY CHECKED BY DATE Rev. 3/20102 Page I of I Tei.,/ ofLos Alms Hills �� BARRIE D. COATE and ASSOCIATES HodaIDaal ConstA15" 23535 SUMMIt oed Log Ca S, CA 95033 408/353-1052 . ATTACHMENT (o TREE SURVEY AND PRESERVATION RECOMMENDATIONS DURING WIDENING FOR A FIRE TRUCK TURNAROUND AT THE LANDS OF COHEN 13303 WILDCREST DRIVE LOS ALTOS HILLS Prepared at the Request of: Debbie Pedro Town of Los Altos Hills 26379 Fremont Road Los Altos Hills, CA 94022 Site Visit by: Michael L. Beach Consulting Arborist May 26, 2005 Job #05-05-083 RECEIVED JUN 09 2005 TOWN OF LAS ALTOS HILLS TREE SURVEY AND PRESERVATION RECOMMENDATIONS DURING WIDENING FOR A FIRE TRUCK TURNAROUND AT 1 THE LANDS OF COHEN 13303 WRDCREST DRIVE LOS ALTOS HILLS Assignment I was asked by Debbie Pedro, Planner, Town of Los Altos Hills, to prepare a Tree Protection Plan for the trees located new the proposed driveway widening for a fire truck tum around at the Cohen Residence, 13303 Wildcrest Drive, Los Altos Hills, California. The plans provided for this evaluation are Construction Plans, Prepared by Barton Architects, Palo Alto, Sheets AD. 1, C-1, C-2, A2.1 -A2.6, A3.1 -A3.6, dated 4-18-05. Summary There are 7 trees on this site in the area of the proposed driveway construction which are identified and briefly described in this report. The expected construction risks based on the plans are described. Trees #1 and 2 would be removed with the implementation of this plan Trees #3, 4, and 5 would be exposed to moderate risk. These should survive in fine condition. Tree #6, a 35 -inch diameter valley oak (Quercus lobala), would be exposed to severe risk. However, it may survive if all mitigation procedures are thoroughly carried out in a timely fashion. The risk to Tree #7 should be minimal Observations The existing Cohen residence at 13303 Wildcrest Drive, Los Altos Hills and the long driveway to this residence is located on a south -facing slope in a dense oak woodland. The proposed construction plan would widen the existing driveway new the residence in order to provide a turn around access for a fire truck. There are 7 trees on this property located new the proposed grading area. The attached map shows the locations of these 7 trees and their approximate canopy dimensions. The 7 trees are classified as follows: Trees # 1, 4, 6— Valley oak (Quercus lobata) Tree # 2 — Coast live oak (Quercus agrifolia) Trees # 3, 7 — California Blue oak (Quercus douglasii) Tree # 5 — California buckeye (Aesculus californica) The particulars of these trees (species, Trunk diameter, height, spread, health, and structure) are included in the attachments that follow this text. Tree #6 has a moderately sparse canopy and, for this reason, is considered to be in only fair condition. However, it benefits from an irrigation system designed to water the adjacent shrubs. The irrigation system appears to be a fairly recent addition. Tree #6 PREPARED BY: MICHAEL L. BENCH, CONSULTING ARBORIST MAY 26, 20115 TREE SURVEY AND PRESERVATION RECOMMENDATIONS DURING WIDENING FOR AFIRE TRUCK TURNAROUND AT THE LANDS OF COHEN iM3 WILDCREST DRIVE LOS ALTOS HILLS appears to be improving, because the existing canopy, though sparse, has rich green leaf color and appears vigorous. All of the other 6 trees are in good to excellent condition. The root collars of Trees #1, 2, 3, 4, and 5 are covered by soil. This condition may expose them to root collar diseases, such as oak root fungus (Armillaria mellea), which can kill infected trees over time. This risk may be greatly reduced or eliminated by removing the soil around the base of the trunks until the tops of the buttress roots are exposed. Risks to Trees by Proposed Construction The widening of the driveway on the south side as proposed would result in the removal of Trees 41 and 2. A retaining wall is proposed at the edge of the new driveway on the south side. This retaining wall poses at least a moderate risk to the trees located down slope from this construction. Trees #3, 4, and 5 are the nearest trees located down slope from the proposed retaining wall. These 3 trees would be expected to suffer the loss of a portion of their absorbing root systems. The total absorbing root loss is estimated to be approximately 10-15% of their total absorbing root mass. This would be an acceptable quantity of root loss, provided these trees would be irrigated during the dry months of the year during the entire construction process. Trees 93, 4, and 5 would also be at risk of having their root collars covered by soil moving downslope during trenching for the retaining wall. In addition to Trees 43, 4, and 5, there are other oak trees, not included in this report, located still further down slope that could be adversely affected if soil were allowed to slide down slope to cover their root collars. Should Trees #3, 4, and 5 be adequately protected during this construction, the other trees located further down slope would also be protected. It would be essential to prevent soil from moving downslope to cover the root collars of any of the existing trees. The widening of the existing driveway will also require a cul into the slope on the north side. A retaining wall is also proposed for the retention of the soil on the north side slope. This retaining wall is proposed approximately 13 feet from the trunk of valley oak Tree 46 across approximately 1/3 of the width of its root zone. However, the actual soil cut for this retaining wall is estimated to occur approximately 10-11 feet from the trunk of Tree #6, a 35 -inch diameter valley oak in fair condition. In most circumstances. I would require that the nearest soil cut to a tree of this size be a minimum of 15 feet from the trunk, which equates to 5 times the trunk diameter. This distance of 15 feet would result in an acceptable quantity of root loss, provided the tree would be irrigated for at least 2 years. A soil cut 10-11 feet from the trunk, in my opinion, would be quite severe. However, Tree #6 may have a reasonable chance of survival, provided it is thoroughly irrigated and mulched (described in the Tree Protection Plan). The apparent risk to Tree #7 by the proposed plan would be minimal. Irrigation should PREPARED BY: MICHAEL L. BENCH, CONSULTING ARBORIST MAY 26, 2006 THE LANDS OF WHEN 13303 WUXREST DRIVE LOS ALTOS HILLS be provided to this tree as a precaution. TREE PROTECTION PLAN Irrigation 1. Tree #6 would have a reasonable chance of survival if it is irrigated before, during, and after construction. I recommend that a drip line or a soaker hose be placed on the soil surface to irrigate the entire root zone, particularly the north side but no closer than 3 feet from the trunk (see attached sketch). The objective would be to encourage new absorbing root development throughout the entire root zone, except for the area of roots lost by the retaining wall construction. It would be preferred if possible to initiate irrigation 1-2 month's prior the construction, but it would be essential to provide irrigation to Tree #6 for at least 2 years following construction. I do not recommend sprinkler irrigation because of the problems with adequate penetration on a slope. It is essential that sprinkler irrigation must not be designed to strike the trunks of trees, especially the oak trees, on a regular basis. 2. I recommend that Tree #6 be irrigated during the dry months (any month receiving less than 1 inch of rainfall) before, during, and after construction as previously described. Irrigate a minimum of 10 gallons for each inch of trunk diameter every two weeks. Once again, a soaker hose or a drip line is preferred for this purpose. 3. 1 recommend that Trees #3, 4, and 5 be irrigated with the same quantity and frequency, as Tree 96. It should be sufficient to irrigate Trees #3, 4, and 5 only during the construction period. 4. As a precaution, it would not harm Tree #7 to receive irrigation as described during the construction period. Mulching 1. The entire area inside the dripline of Tree #6 most be mulched with the exception of the construction area. Mulching consists of a protective material (wood chips, gravel) being spread over the root zone inside the dripline. This material must be 4 inches in depth after spreading, which must be done by hand. I prefer coarse wood chips because it's organic, and degrades naturally over time. Wood chips must be '/4 to % inch in diameter primarily. One supplier is Reuseq Inc., 370 Santana Dr., Cloverdale, CA 95425, (707)894-4224. Protective Fencing 1. I recommend that a silt fence be installed on the uphill side of the trunks of Trees # 3, 4, and 5 to prevent soil from moving down slope. This fence must be sufficiently strong to prevent soil movement down slope. Soil that builds against this fence must be removed prior to removal of the fence. Root Collar Excavations 1. I recommend that the root collars of Trees #3, 4, and 5 be excavated by hand PREPARED BY. MICHAEL L BENCH, CONSULTING ARBORIST MAY 26, nM5 TREE SURVEY AND PRESERVATION RECOMMENDATIONS DURING WIDENING FOR A FIRE TRUCK TURNAROUND AT 4 THE LANDS OF COHEN 13303 WILDCREST DRIVE LOS ALTOS HILLS exposing to tops of the 5-6 buttress roots. It may be necessary to install a wall of dry laid cobblestones to hold the soil above the root collars to prevent further soil intrusion over the root collars of these trees. This could be done at the end of the construction process. Pruning 1. It appears that it may be necessary to prune Trees 43 and 4 for construction access. Pruning must be limited to a maximum of 1/3 of the canopy of any tree. Also, any pruning must be done by an arborist certified by the ISA (International Society of Arboriculture) and according to ISA, Western Chapter Standards, 1998. Future Landscaping Landscaping following construction could be highly destructive to existing trees unless the following minimal precautions are observed: L Landscape irrigation trenches must be a minimum distance of 10 times the trunk diameter from the trunks of trees. 2. Landscape materials (cobbles, decorative bark, stones, fencing, etc.) must not be installed directly in contact with the bark of trees because of the risk of serious disease infection. 3. No rototilling is allowed inside the dripline. 4. Sprinkler irrigation must not strike the trunks of trees. 5. The minimal spacing for planting inside the driplines of existing oak trees must be 6 feet or greater. Bear in mind that the soil preparation of a large area of the root zone for planting a ground cover could kill an established oak tree. Use only small plants, 1 gallon size preferred. The plants that are planted inside the driplines of oak trees must be of species that are compatible with the environmental and cultural requirements of oaks trees. A publication about plants compatible with California native oaks can be obtained from the California Oak Foundation, 1212 Broadway, Suite 810, Oakland 94612. RespectsM i d, Michael L. Bench, Associate r - tLtiPttrt R � MLB/slp PREPARED BY: MICHAEL L. BENCH, CONSULTING ARBORIST MAY 26, 2005 TREE SURVEY AND PRESERVATION RECOMMENDATIONS DURING WIDENING FOR A FIRE TRUCK TURNAROUND AT THE LANDS OF COHEN 13303 WRDCREST DRIVE LOS ALTOS HILLS Enclosures: Assumptions and Limiting Conditions Tree Data Charts Tree Protection Before, During and After Construction Protective Fencing/Silt Fencing PREPARED BY: MICHAEL L. BENCH, CONSULTING ARBORIST MAY ZS, M5 0 N n o" O U,�ry �o E o > z y 0 o Q 1NK1dSNVa1 _ _-______ ___;:__ __:.__ --- :___ _ �_ _ - (CI)A11aOlaa IVAOW3a 1 E m ItlAOW38 aN3WWO03a E______________________________________ _ _�___ ___F___ ___,___ ___F___ ______ ___F___ ___�_._ _ E N3Ntl13an101d 1 1 1 a 3Aa3S3ad E (S-0 3Stl3Sla atl11001008 (S-l)03a3A00 atl1100100a o ______________________________________ ___:___ __:_._ ---:--- --------___ ___ ___ ___ ___ n (S-UAV030 NNnal ___ - _{ ___ ___F___ ___{___ ___F__. __.�.._ ._.F___ ___{___ ___I m_______________ m (S- OOOM Ob30 P - i 1. 'p 3Stl3S10 NMOaO 3381 1 ----- (S-lJ S103SNI m (9-0 AlI80INd ONINnad a______________________________________ _______ ___f___ ___,___ ___F___ ___{___ ___F___ __- m # 03033N 5319tl0 I 1 1 1HOI3M-ON3 3AOW3a I j I I 1 __ __�___ ___;___ _ _;___ ___;___ __ ;___ ___;___ _ - ' m ONISIVa NMOaO 1 u_____________i NOI1VaO1S3a NMOaO 1 7 1 ONINNIHl NAA080 a ONINtl3l0 NMOaO Z✓4)ONI VYl (1aVZVH I ---------- --------------------------- --- ----- -_--- _______ o (0l -Z) ONIIVa NOUICINOD y______________________________________ C (9-03an10na1S _______ ________________ ___{_-_ ---�-.- --- --- ___F___ --- {--------F___ ___{___ ___� O---------------------- (S-l)H1lb3H N1 N1 G31VWI1S9 0V38dS _____________________________ ... __;_. 031VINIIS31HOI3H n1 of o1 o1 01 .1 n1 NI NI N, N1 NI MI 8 30N31d3jiNno8io --- -- ---+--- - -r-- ---`-- - -r-- ---r--- 01 m1 1 H9O �� ro1 e1 1 W31SAS-I1lnW --------------------------------------- 133j Ul-9 6313WV10 0l __ o___ _o ol___ _o:___ off___ _o,_ 1 21 ^' ,61 01 61 MI '1 i Q Q E 8 = v1 V V P z im O EC S iA Is Oi R mi W N NI ji N a 2i w O; o 1pi perd�-I U OI u �< `p'I> >i OI m '1 o 01 o m1 0' >i vi < >i m1 E>I 1 r 0 N n o" O U,�ry �o E o > z y 0 o Q BARRIE D. COATE AND ASSOCIATES Horticultural Consultants (408)353-1052 Fax (4-08) 353-1238 23535 Summit Rd. Los Gatos, CA 95033 TREE PROTECTION BEFORE, DURING, AND AFTER CONSTRUCTION These are general recommendations And may be superseded by site-specific instructions BEFORE Plan location of trenching to avoid all possible cuts beneath tree canopies. This includes trenches for utilities, irrigation lines, cable TV and roof drains. Plan construction period fence locations which will prevent equipment travel or material storage beneath tree canopies. Install fences before any construction related equipment is allowed on site. This includes pickup tmcks. Inform subcontractors in writing that they must read this document. Require return of signed copies to demonstrate that they have read the document. Prune any tree parts, which conflict with construction between August and January. Except for pines which may be pruned between October -January. Only an ISA certified arborist, using ISA pruning instructions may be used for his work. If limbs are in conflict with the construction equipment before the certified arborist is on-site, carpenters may cut off offending parts of 6" diameter or less, leaving an 18" long stub, which should be re -cut later by the arborist. Under no circumstances may any party remove more than 30% of a trees foliage, or prune so that an unbalanced canopy is created. DURING Avoid use of any wheeled equipment beneath tree canopies. Maintain fences at original location in vertical, undamaged condition until all contractors and subcontractors, including painters are gone. Clear root collars of retained trees enough to leave 5-6 buttress roots bases visible at 12" from the trunk. Irrigate trees adjacent to construction activity during hot months (June -October). Apply 10 gallons of water per 1" of trunk diameter (measured at 4 ''/s') once per 2 week period by soaker hose. Apply water at the dripline, or adjacent to construction not around the trunk. Apply mulch to make a 3" deep layer in all areas beneath tree canopies and inside fences. Any organic material which is non toxic may be used. AFTER Irrigate monthly with 10 gallons of water per 1" of trunk diameter with a soaker hose, placed just inside the dripline. Continue until 8" of rain has fallen. Avoid cutting irrigation trenches beneath tree canopies. Avoid rototilling beneath tree canopies since that will destroy the small surface roots which absorb water. Avoid installation of turf or other frequently irrigated plants beneath tree canopies. 31 a 4 D � ry �+ d C ri U D V — .N U n E V A O N u m C 9 r1 W: N 6 O m M i N d L N M w 0 ? N O O y F w k u Y u a N C N d u u a o ^J � p F U w u o c a N r W V d i a ry C � O 4 T F H Q u F y OQ1 CUo � N — Hw d �o E mU N ¢ N OO ] m N v az °] =¢ j% 00 �^ N S U a 4 D � ry �+ d _� ri U D V — d a U n E n > A O N u 9 r1 W: N 6 s M i N d L G 1 M w 0 ? N O O � F w k u Y u a N C N F u u a o w u o c a N r ri V d i a ry C O. O 4 T F H o k u F y a Hw d �o E mU D � ry = D = _� D V — d a U n > d a _ � L p o c V C L L U m d VIII U C N O V — CN C O LL � L W m BARRIE D. COATE and ASSOCIATES HONNWral Consawnts 23535 Summit Road Los Gatos. CA 95033 408/35}1052 1. Any legal description provided to the appraiser/consultant is assumed to be correct. No responsibility is assumed for matters legal in character nor is any opinion rendered as to the quality of any title. 2. The appraiser/consultant can neither guarantee nor be responsible for accuracy of information provided by others. 3. The appraiser/consultant shall not be required to give testimony or to attend court by reason of this appraisal unless subsequent written arrangements are made, including payment of an additional fee for services. 4. Loss or removal of any part of this report invalidates the entire appraisal/evaluation. 5. Possession of this report or a copy thereof does not imply right of publication or use for any purpose by any other than the person(s) to whom it is addressed without written consent of this appraiser/consultant. 6. This report and the values expressed herein represent the opinion of the appraiser/consultant, and the appraiser's/consultant's fee is in no way contingent upon the reporting of a specified value nor upon any finding to be reported. 7. Sketches, diagrams, graphs, photos, etc., in this report, being intended as visual aids, are not necessarily to scale and should not be construed as engineering reports or surveys. 8. This report has been made in conformity with acceptable appraisal/evaluation/diagnostic reporting techniques and procedures, as recommended by the International Society of Arboriculture. 9. When applying any pesticide, fungicide, or herbicide, always follow label instructions. 16.No tree described In this report was climbed, unless otherwise stated. We cannot take responsibility for any defects which could only have been discovered by climbing. A full root collar inspection, consisting of excavating the soil around the tree to uncover the root collar and major buttress roots, was not performed, unless otherwise stated. We cannot take responsibility for any root defects which could only have been discovered by such an inspection. Arborists are tree specialists who use their education, knowledge, training, and experience to examine trees, recommend measures to enhance the beauty and health of trees, and attempt to reduce risk of living near trees. Clients may choose to accept or disregard the recommendations of the arborist, or to seek additional advice. Arborists cannot detect every condition that could possibly lead to the structural failure of a tree. Trees are living organisms that fail in ways we do not fully understand. Conditions are often hidden within trees and below ground. Arborists cannot guarantee that a tree will be healthy or safe under all circumstances, or for a specified period of time. Likewise, remedial treatments, like medicine, cannot be guaranteed. Trees can be managed, but they cannot be controlled. To live near trees is to accept some degree of risk. The only way to eliminate all risk associated with trees is to eliminate all trees. �, Barrie D. Coate ISA Certified Arborist Horticultural Consultant CODMEC. I SHEET UFC Apppendix ur UFC 902.2.4.1 UFC 901.3 FIRE DEPARTMENT SANTA CLARA COUNTY 14700 Winchester Blvd., Los Gatos, CA 95032-1818 (408) 378-4010 • (408) 378-9342 (fax) • wwtv.sccfd.org PLPNREVIEWNUABER 05 1235 BLOO PERMn NUMBER ATTAGNMENT 7 CONTROL NUMBER FlLENUMBEN S1-05-SD-ZP-GD-V DEVELOPMENT REVIEW COMMENTS NO.I REWIREMENT of site plan for proposed 635 square foot addition to an existing 3,355 foot single family residence with an attached garage. of this Developmental proposal is limited to acceptability of site access and tpply as they pertain to fire department operations, and shall not be !d as a substitute for formal plan review to determine compliance with model codes. Prior to performing any work the applicant shall make ion to, and receive from, the Building Department all applicable :tion permits. Iw: The fire flow for this project is 1000 gpm at 20 psi residual tsted fire flow is available from area water mains and fire are spaced at the required spacing. apparatus (Engine)Access Driveway Required: Provide an access driveway a paved all weather surface, a minunum unobstructed width of 14 feet, al clearance of 13 feet 6 inches, minimum circulating turning radius of 36 feet de and 23 feet inside, and a maximum slope of 15%. Installations shall Irm to Fire Department Standard Details and Specifications sheet D-1. ing of Required Driveway Installations: Required driveway installations be constructed and accepted by the Fire Department, prior to the start of Dustible construction.Note that building permit issuance may be withheld until .Rations are completed.Temporary driveways may be approved on a case by basis. CSy PLGNS SPECS NEW RMDL AS OCCUPMICT CONBT.TTPE ApgluntWnx DATE PAGE LAH E3❑ El [:] ❑ BARTON ARCHITECTS 5/2/2005 1 1 OF SECIFLOOs GIE1 LOAD DESCSIpIpN By Residential Development Rucker, Ryan NAME D. PROJECT DCATIDN SFR- COHEN 13303 Wildcrest Organized as the Santa Clara County Central Fire Protection District Serving Santa Clam Countyand the mmmumht of Campbell, Cupenlno, Los Alw, Los Altos HVIs, Los Caton, Monte Serer, Morgan Hill, and Saratoga :OOMEC. I SHEET FIR►: DEPARTMENT SANTA CLARA COUNTY 14700 Winchester Blvd., Los Gatos, CA 95032-1818 (408) 378-4010 • (408) 378-9342 (fax) • a .sccfderg .NREVIEWNUMBER 05 1235 BLDG MMMT N MBER CprtROL NUMBER NLENMMBER 81-05-SD-ZP-GD-V DEVELOPMENT REVIEW COMMENTS REWIREMEM =narcmenc inngmet vnveway ium-arouna nequlrea: rrovtae an ,ed fire department engine driveway turnaround with a minimum radius of outside and 23 feet inside. Installations shall conform with Fire Department rd Details and Specifications D-1. Clry PLN6 SPECS NEW RMM AS OCCUP y CONST. TYPE GppgcPMMms DRTE PiGE AH ❑ ❑ ❑ ❑ ❑ BARTON ARCHITECTS 5/2/2005 2 1 OF cJPwoR PREN w\o oEscRiPnoN BY Residential Development Rucker, Ryan \ME OF PROJECT --RT3 SFR- COHEN 13303 Wildcrest the Santa Clara Countv Central Fire Protection District SeMng Svnta Clam County and the rommunities of Cam➢hell, Cucertino, Los Altos, Los Altos Hills, Los Gatos, Mone Sereno, Morgon HiII, Bnd Saratoga ATTACHMENV ( b May 24, 2005 L0115 TO: Debbie Pedro Planner TOWN OF LOS ALTOS HILLS 26379 Fremont Road Los Altos Hills, California 94022 SUBJECT: Geotechnical Peer Review RE: Cohen, Addition and Repair 13303 Wildcrest Drive File #81-05-SD-ZP-GD-VAR-CDP At your request, we have completed a geotechnical peer review of the subject application using: • Geotechnical Investigation (report), prepared by Romig Engineers, dated September 28, 2004; • Civil Plans (2 sheets), prepared by Giuhani & Kull, dated April 18, 2005; and • Architectural Plans (12 sheets), prepared by Barton/Architect, dated April 21, 2005. In addition, we have reviewed pertinent technical documents from our office files and completed a recent site inspection. DISCUSSION The applicant proposes to remodel portions of the existing residence, convert the existing garage into a bedroom, and convert the existing carport into an enclosed garage, laundry and storage area. We understand that foundation underpinning is proposed for portions of the existing residence. As part of the project, the portion of the driveway alignment near the residence will be extended and increased in width requiring construction of new upslope and downslope retaining walls. We understand that the existing site septic leachfield is to be removed and that the residence will be served by extension of a sanitary sewer lateral along the driveway and connected to the Wildcrest Drive force main. The majority of the driveway will be widened, requiring construction of upslope retaining walls on the order of 3 feet in height. Debbie Pedro May 24, 2005 Page L0115 The proposed house site is located across terraced cut -fill pads situated on a steep, south -facing hillslope. Various portions of the existing residence show signs of distress and the Project Geotechnical Consultant has determined that floors of the garage and residence are out of level by approximately 2.5 inches. Lateral and vertical movement of existing site fill is suspected of contributing to observed distress. Several cracks were observed along the downslope side of the existing driveway (to 0.5 inch in width located 50 feet east of the residence) suggesting the presence of underlying, non - engineered fill materials. Apparent fill materials south of the driveway reach maximum slopes of approximately 1.5:1 (horizontal:vertical). Drainage is generally characterized by sheet flow to the south intercepted by a local creek channel. According to information obtained from exploratory borings in the area of the residence, sandstone bedrock of the Santa Clara Formation was encountered beneath the site. The bedrock is overlain by approximately 2 to 10 feet of silty to sandy clay (artificial fill and colluvium). The potentially active Monta Vista fault is mapped approximately 0.5 mile southwest of the property. The San Andreas fault is located approximately 3.5 miles southwest of the property. CONCLUSIONS AND RECOMMENDED ACTION Based on our review, the proposed development is constrained by potentially expansive soils, existing fill materials not meeting current engineering standards, and anticipated very strong seismic shaking. The Project Geotechnical Consultant has performed an investigation of the subject property and provided recommendations primarily for the proposed remodeling and foundation underpinning that, in general, appear appropriate for identified site constraints. It appears that the layout of proposed site improvements is geotechnically feasible. However, additional geotechnical evaluations (and possible subsurface investigation) are warranted for the design of project retaining walls. The submitted geotechnical report does not provide geotechnical design criteria for retaining walls. The proposed retaining wall along the southern side of the driveway warrants consideration of a pier -supported design to address the presence of existing fill materials. Additional design criteria should be prepared for retaining walls along the northern side of the driveway (including the fire truck tum -around area). Consequently, we recommend that the following Items 1 and 2 be addressed prior to acceptance of construction documents for building permit plan -check. 1. Suuolemental Geotechnical Evaluations Investigation tion - The Project Geotechnical Consultant should review all geotechnical aspects of the current development plans and prepare recommended geotechnical design parameters for project retaining walls. A pier -supported retaining wall design should be considered along the southern side of the Debbie Pedro Page 3 May 24, 2005 L0115 driveway. Additional subsurface exploration should be completed if deemed necessary. Consideration should be given to the potential merits of removing and replacing existing fill materials that may influence the performance of the driveway. The results of the supplemental evaluations should be summarized by the geotechnical consultant in a letter and submitted to the Town, for review by the Town Geotechnical Consultant, prior to acceptance of documents for building pemut plan check. 2. Geotechnical Plan Review - The applicant's geotechnical consultant should review and approve all geotechnical aspects of the project building and grading plans (i.e., site preparation and grading, site drainage improvements and design parameters for foundations, retaining walls and driveway) to ensure that their recommendations have been properly incorporated. The results of the plan review should be summarized by the geotechnical consultant in a letter and submitted to the Town Engineer for review and approval prior to issuance of building permits. 3. Geotechnical Field Inspection - The geotechnical consultant should inspect, test (as needed), and approve all geotechnical aspects of the project construction. The inspections should include, but not necessarily be limited to: site preparation and grading, site surface and subsurface drainage improvements, and excavations for foundations and retaining walls prior to the placement of steel and concrete. The results of these inspections and the as -built conditions of the project should be described by the geotechnical consultant in a letter and submitted to the Town Engineer for review prior to final (as -built) project approval. LIMITATIONS This peer review has been performed to provide technical advice to assist the Town in its discretionary permit decisions. Our services have been limited to review of the documents previously identified, and a visual review of the property. Our opinions and conclusions are made in accordance with generally accepted principles and practices of the geotechnical profession. This warranty is in lieu of all other warranties, either expressed or implied. Respectfully Submitted, COTTON, SHIRES AND ASSOCIATES, INC. TOWN GEOTECHNICAL CONSULTANT Debbie Pedro Page 4 Ted Sayre Supervising Engineering Geologist CEG 1795 Patrick O. Shires Principal Geotechnical Engineer GE 770 POS:T5:rb May 24, 2005 L0115 Cc -4 F- Al ENVIRONMENTAL DESIGN COMMITTEE RECEIVED NEW RESIDENCE EVALUATION A ,; 4AN-r Applicant's Name: TOWN OFLOSaI i0S HILLS Address: Existing Trees: (Comment on size, type, condition, location with respect to building site. Recommended protection during construction.) Proposed Grading: (Impact on water table, nearby vegetation. Erosion potential. All grading at least 10' from property line?) Creeks and drainage: (Should a conservation easement be recommended? Sufficient space between house and conservation easement for circulation. Will construction impact wildlife migration (bridges, fences)? Is there a need for removal of invasive species?) Siting: (View impact: ridgeline, across valley, on neighbors. Will driveway impact neighbors' privacy (lights, noise)? Recommended mitigation (height, color, landscape).) I I_ Other Comments: