Loading...
HomeMy WebLinkAboutItem 4.1L1.1 TOWN OF LOS ALTOS HILLS July 14, 2005 Staff Report to the Planning Commission RE: SITE DEVELOPMENT PERMIT FOR A NEW RESIDENCE AND SWRYD IING POOL; LANDS OF GOESE; 13480 WILDCREST DRIVE; #90-05-ZP-SD-GD. FROM: Debbie Pedro, AICP, Senior Planner APPROVED BY: Carl Cahill, Planning Director C. C. RECOMMENDATION: That the Planning Commission: Approve the requested Site Development Permit, subject to the recommended conditions in Attachment 1 ALTERNATIVE Direct the applicant to redesign the proposed residence to reduce the visible profile or height of the house. The subject property is located on the crest of a ridgeline near the end of Wildcrest Drive. Surrounding uses include single-family homes across Wildcrest Drive to the north, east, and south. A 27,000 sq. ft. new residence (Lands of Evershine) is currently under construction on the adjacent parcel to the west. The applicant proposes to demolish a single story residence with a detached garage on the property and construct a new two- story residence with a garage, basement, and swimming pool. The development proposal also includes a partial re -alignment of the upper driveway and the construction of a fire truck turnaround on the south side of the new building. CODE REOUIREMENTS As required by Sections 10-2.301 and 10-2.702 of the Site Development Code, this application for a new residence has been forwarded to the Planning Commission for review and approval. Criteria for review from the Site Development Code include visibility, building siting, grading, drainage, pathways, landscape screening and outdoor lighting. Zoning Code review encompasses compliance with floor and development area limitations, height, setbacks, and parking requirements. Staff Report to the Planning Commission Lands of Geese 13480 Wildcrest Drive July 14, 2005 Page 2 of 14 DISCUSSION Site Data: Gross Lot Area: 1.897 acres Net Lot Area: 1.897 acres Average Slope: 26.2% Lot Unit Factor: 1.238 Floor Area and Development Area: Area (sq. ft.) Maximum Existing Proposed Increase Remaining Development 11,049 12,600 10,955 (1,645) 94 Floor 6,425 4,017 6,414 2,397 11 Site and Architecture The applicant is requesting approval of a Site Development Permit to construct a 5,501 square foot two-story residence with a 714 square foot basement, a 913 square foot attached garage, and a 817 sq. ft. swimming pool. The parcel is located on the crest of a ridgeline with moderately steep to very steep slopes to the north, east and south. The existing residence is located on a graded cut -fill pad near the crest of the knoll. Constrained by steep slopes, the new residence will be constructed in approximately the same area as the existing residence. The two-story building meets the setback, height, floor area and development area requirements established in Title 10, Zoning and Site Development, of the Los Altos Hills Municipal Code. The new residence is located a minimum of 55' from the north (front) property line, 30' from the west (side) property line, and 97' from the east (side) and south (rear) property lines. The maximum building height on a vertical plane is 27' and the maximum height of the building (including chimneys and appurtenances) from the lowest point to the highest point is 35'. The ground floor of the new residence has 4,083 sq. ft. of living area which includes a foyer, living room, dining room, kitchen, library and two guest bedroom/offices. The second floor has 1,418 sq. ft. of living space with two bedrooms and bathrooms. A 913 sq. ft. three car garage sits below the guest bedroom at the east end of the building and a 714 sq. ft. basement beneath the kitchen serves as a storage and mechanical room. The basement is fully underground and exempt from floor area calculations pursuant to Section 10-1.208 0£ the Municipal Code. Staff Report to the Planning Commission Lands of Goese 13480 Wildcrest Drive July 14, 2005 Page 3 of 14 Proposed exterior materials include a cement plaster exterior with bay fieldstone veneer, slate roof, and mahogany wood windows. Due to the visibility of the property, staff has required in Condition #12 that roof and exterior materials conform to light reflectivity values of 40 and 50 respectively. Driveway & Parking Driveway access to the property will be kept at its current location. The upper portion of the driveway is proposed to be re -aligned further to the south and a new section of the driveway that includes a required fire truck turnaround will be constructed. Several significant trees located east of the existing home will be removed in order to accommodate the new fire truck turnaround. In addition, grading (up to 3' fill) and terraced retaining walls up to 3' in height will be located along the south side of the new driveway. A garage will provide three (3) covered parking spaces with standard dimensions of 10' x 20'. One (1) additional outdoor parking space is located directly east of the garage outside of the required setbacks. Trees & Landscaping Existing landscaping on the property includes two rows of oleander hedges along the driveway and a number of overgrown shrubs around the building site. A variety of trees are located throughout the property including cedar, pine, walnut, pepper, cypress, and oaks. The remnant of an orchard is found on the north facing hillside slope where several fruit trees remain. The trees proposed to be removed as part of this site development proposal are shown on the tree removal plan (Sheet L3). It should be noted that several mature trees including a cedar, two cypresses, and a walnut tree that currently provides substantial screening of the building site from the east side will be removed to accommodate the proposed fire truck turnaround. The building site is on a hilltop and is highly visible from neighboring properties and streets. Removal of existing trees and vegetation will render the new two-story building even more visible. The two-story structure will appear to dominate the natural landscape, particularly when viewed from the north, east, and south directions. As a mitigation measure, staff recommends that for each mature screen tree removed as a result of the new construction, the applicant should be required to replant three (3) mature tree specimen (minimum 20' tall x 10' wide) on the property in locations that will help break up the view of the house from off site. Staff recommends a total of fifteen (15) replacement trees to be planted for screening with at least one mature tree planted in the lawn area between the house and the pool. (Condition # 2) The condition is reasonable because while other two-story homes were observed on surrounding ridges and hillsides, most were partially screened with mature vegetation. In addition, Site Development Code section 10-2.702.c states that "the location of all structures should create as little disturbance as possible to the natural landscape." It appears that more effort could have Staff Report to the Planning Commission Lands of Goese 13480 Wildcrest Drive July 14, 2005 Page 4 of 14 been made by the applicant to utilize the existing developed area and avoid the removal of the existing trees. Proposed Tree Removal Around Building Site Recommendation: •4,. �� 3 to 1 replacement of mature screen trees t # Open Space 3 x 5 trees = 15 replacement trees d� Easement it (� i % as( ! t Rideelines. Hilltops, and Hiehly Visible Lots Pursuant to Section 10-2.702 of the Site Development Ordinance, "ridgelines, hilltops, and highly visible lots shall be preserved by the siting of structures to take advantage of natural topographic or landscape features which would cause structures to blend with their natural surroundings." In reviewing the proposal, the Planning Commission has to consider whether the new residence conform with the following guidelines: (1) Single story buildings and height restrictions may be required on hilltops, ridgelines, and highly visible lots. (2) Cut foundations should be used in place of 611 on hilly terrain. (3) Native or naturalized vegetation should be used to conceal structures wherever possible. Staff Report to the Planning Commission Lands of Currie 13480 Wildcrest Drive July 14, 2005 Page 5 of 14 (4) Structures may be located on ridgelines or hilltops only when they can be rendered unobtrusive by one (1) or more of the following techniques. (i) The use of natural vegetation and/or added landscaping. (ii) The use of a low -profile house, with a sloping roofline and foundation, that follows the natural contours of the site. (iii) The use of exterior roofing and siding materials and colors that blend with the natural landscape. (5) Hilltops or ridgelines shall not be cut down, flattened, or similarly graded to create a building pad in excess of the actual area covered by the principal residence. By utilizing a step foundation, sloping roofline, and natural exterior materials and colors, the applicant has demonstrated some efforts to create an unobtrusive, low visual profile home. However, the site design, which pushes the building to the outermost edge of the building pad, leaves little or no opportunity for planting mound the perimeter of the structure at pad elevation where screening is most effective. As stated earlier, the north, east, and south elevations of new home will be highly visible from neighboring properties and streets. Planting substantial size trees and shrubs on the upper slopes around the building area will be necessary to achieve any reasonably effective screening to reduce the visual impact of the new structure. After completion of rough framing and prior to the time of the pre -rough framing inspection by the Planning and Engineering Departments, the applicant will be required to submit a landscape screening and erosion control plan for review by the Planning Commission and any planting required for screening or erosion control will be required to be planted prior to final inspection. (Condition # 2) Outdoor Lighting The proposed lighting for the exterior of the house is shown on the lighting plan (sheet IA). No skylights are proposed for the house and no lighting is proposed in the setbacks. No lighting was shown at the driveway entrance. Staff recommends that the exterior lighting be approved as submitted with a condition limiting exterior lighting to one fixture per doorway with the exception of two lights at the main entrance of the house, at double doors, and the garage doors. (Condition # 7). Open Space Easement As a condition for site development, an Open Space Easement will be required over the southeastern portion of the property where the slope of the land is 30% or greater. In Staff Report to the Planning Commission Lands of Goese 13480 Wildcrest Drive July 14, 2005 Page 6 of 14 addition, staff has included condition #6 which requires all existing landscaping within the Open Space Easement be retained. Drainase 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. Water runoff generated from the new development will be collected and carried to six (6) rip -rap dissipators around the property. The applicant's engineer has provided a hydrology study which included storm flow analysis and calculations showing that the proposed drainage improvements will mitigate impacts of the site development and the quantity and flow rate of onsite surface runoff will not increase. The Engineering Department will review and approve the final drainage plan prior to acceptance of plans for building plan check. Final "as -built" grading and drainage will be inspected by the Engineering Department, and any deficiencies will be required to be corrected prior to final inspection. Gradine Total grading quantities include 480 cubic yards of cut (basement, house, and swimming pool) and 205 cubic yards of fill (driveway and east of the main residence). The Engineering Department has reviewed the proposed grading and concluded that it is in conformance with the Town's grading policy. Staff Report to the Planning Commission Lmds of Goese 13480 Wildcrest Drive July 14,2005 Page 7 of 14 Fire Department Review The Santa Clara County Fire Department has reviewed the proposal and is requiring a fire truck turnaround on the property which has been incorporated into the driveway plan. Additional conditions including installation of fire sprinklers throughout the building and premise identification are included as conditions #27-29. Committee Review The Pathways Committee recommends a pathway in -lieu fee which is included as condition #26. The Environmental Design Committee noted that this house is on a ridgeline and should be limited to one story. Furthermore, the committee requested that the oak trees behind the existing garage along the west property line be protected and preserved. CEOA STATUS The project is categorically exempt under Class 3 of the State CEQA Guidelines ATTACHMENTS 1. Recommended conditions of approval 2. Site Map 3. Recommendations from Environmental Design Committee dated May 16, 2005 4. Recommendations from Cotton, Shires, and Associates dated June 7, 2005 5. Recommendations from Santa Clara County Fire Department dated May 5, 2005 6. Worksheet#2 7. Development plans: site, topographic, grading & drainage, floor, elevation, section, roof, and lighting plans cc: Brad Blackman, Custom Dreams 300 S. San Antonio Road Los Altos, CA 94022 Staff Report to the Planning Commission Lands of Goese 13480 Wildcrest Drive July 14, 2005 Page 8 of 14 ATTACHMENT 1 RECOMIviENDED CONDITIONS FOR SITE DEVELOPMENT PERMIT FOR A NEW RESIDENCE WITH BASEMENT AND POOL LANDS OF GOESE, 13480 WIIOCREST DRIVE File # 90-05-ZP-SD-GD A. PLANNING DEPARTMENT: 1. No other modifications to the approved plans are allowed except as otherwise first reviewed and approved by the Planning Director or the Planning Commission, depending on the scope of the changes. 2. After completion of rough framing and prior to the time of the pre - rough framing inspection by the Planning and Engineering Departments, the applicant shall submit a landscape screening and erosion control plan for review by the Planning Commission. Particular attention shall be given to plantings which will be adequate to break up the view of the residence and the driveway retaining walls from surrounding properties and streets. The applicant shall replant fifteen (15) mature tree specimen such as quercus agrifolia (minimum 20' tall x 10' wide) on the property in locations that will help break up the view of the house from off site. At least one mature tree shall be planted in the lawn area between the house and the pool. All landscaping required for screening purposes and for erosion control (as determined by the City Engineer) must be installed prior to final inspection of the new residence. 3. A landscape maintenance deposit in the amount of $20,000 shall be posted prior to final inspection. An inspection of the landscape to ensure adequate establishment and maintenance shall be made two years after the installation. The deposit will be released at that time if the plantings remain viable. 4. Prior to beginning any grading operation, all significant trees, including the existing 12" oak tree along the west property line, are to be fenced at the drip line. The fencing shall be of a material and structure (chain-link) to clearly delineate the drip line. Town staff must inspect the fencing and the trees to be fenced prior to commencement of grading. The property owner shall call for said inspection at least three days in advance of the inspection. The fence must remain throughout the course of construction. No storage of equipment, vehicles or debris shall be allowed within the Staff Report to the Planning Commission Lands of Goese 13480 Wildcrest Drive July 14, 2005 Page 9 of 14 drip lines of these trees. Existing perimeter plantings shall be fenced and retained throughout the entire construction period. 5. The property owner shall grant an open space easement to the Town over the southeastern portion of the property where the slope of the land is 30% or greater. 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. 6. All existing landscaping within the Open Space Easement shall be preserved. 7. Outdoor lighting is approved as shown on the approved site 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. The number of lights on the exterior of a structure should be limited to one light per doorway, with the exception of two lights at the main entrance, at double doors or garage doors. Any security lighting shall be limited in number and directed away from clear view of neighbors, and shielding with shrouds or louvers is suggested. Any additional outdoor lighting shall be reviewed and approved by the Planning Department prior to installation. 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 40' from the front property line and 30' 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 applicant shall submit the stamped and signed letter(s) to the Planning Department prior to requesting a foundation inspection. 9. 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 27'-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 Staff Report to the Planning Commission Lands of Goose 13480 Wildcrest Drive July 14, 2005 Page 10 of 14 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. 10. Fire retardant roofing (Class A) is required for all new construction 11. Skylights, if utilized, shall be designed and constructed to reduce emitted light (tinted or colored glass, or other material). No lighting may be placed within skylight wells. 12. Exterior finish colors shall exhibit a light reflectivity value of 50 or less, per manufacturer specifications. Roof materials shall have a light reflectivity value of 40 or less, per manufacturer specifications. All color samples along with the reflectivity value of each sample shall be submitted to the Planning Department for approval prior to acceptance of plans for building plan check. All applicable structures shall be painted in conformance with the approved color(s) prior to final inspection. 13. No new fencing or gates are approved. Any new fencing or gates shall require review and approval by the Planning Department prior to installation. 14. Standard swimming pool conditions: a. Lights shall be designed so that the source is not visible from off-site. b. Drainage outfall structures shall be constructed and located to the satisfaction of the City Engineer. c. Equipment shall be enclosed on all four sides with a roof for noise mitigation and screening. 15. For swimming pools, at least one of the following safety features shall be installed to the satisfaction of the Town Building Official: a. The pool shall be isolated from access to the residence by an enclosure (fencing). It. The pool shall be equipped with an approved safety pool cover. c. The residence shall be equipped with exit alarms on those doors providing direct access to the pool. Staff Report to the Planning Commission Lands of Goese 13480 Wildcrest Drive July 14, 2005 Page 11 of 14 d. All doors providing direct access from the home to the swimming pool shall be equipped with a self-closing, self -latching device with a release mechanism placed no lower than 54 inches above the floor. 16. All properties must pay School District fees to either the Los Altos School District or the Palo Alto Unified School Districtl, as applicable, before receiving their building permit from Los Altos Hills. The applicant must take a copy of Worksheet #2 to school district offices (both the elementary and high school offices in the Los Altos School District), pay the appropriate fees and provide the Town with a copy of their receipts. B. ENGINEERING DEPARTMENT: 17. As recommended by Cotton, Shires & Associates, Inc., in their report dated June 17, 2005, the applicant shall comply with the following: a. Supplemental Geotechnical Evaluations - The Project Geotechnical Consultant should prepare supplemental design recommendations for the currently proposed basement. The consultant should consider project performance benefits of excavating and reworking existing site fill materials to comply with current engineering standards. Of particular concern, is the fill prism and very steep fill slope located immediately northwest of the proposed residence. We note that the current drainage plan shows two proposed energy dissipaters located on very steep slopes near the toe of this fill. The consultant should recommend appropriate revisions to project drainage design. Drainage improvements should be designed to avoid adverse erosional or slope stability impacts. Appropriate documentation to address the above should be submitted to the Town, for review by the Town Geotechnical Consultant, prior to acceptance of documents for building permit plan -check. b. Geotechnical Plan Review - The Project Geotechnical Consultant should review and approve all geotechnical aspects of the development plans (i.e., site preparation and grading, site drainage improvements and design parameters for foundations, etc.) to ensure that their recommendations have been properly incorporated. Staff Report to the Planning Commission Lands of Goese 13460 Wildcrest Drive July 14, 2005 Page 12 of 14 The results of the plan review should be summarized by the geotechnical consultant in a letter and submitted to the Town Engineer prior to acceptance of documents for building permit plan check. 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 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. For further details on the above geotechnical requirements, please refer to the letter from Cotton, Shires & Associates, Inc., dated June 15, 2005. 18. Two sets of a final grading and drainage plans shall be submitted for review and approval by the Engineering Department prior to acceptance of plans for building plan check. 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 letter shall be submitted from the project engineer stating that the drainage improvements were installed as shown on the approved plans and in accordance with their recommendations prior to final inspection. 19. Any, and all, changes to the approved grading and drainage plan shall be submitted as revisions from the project engineer and 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 except to allow for the construction of the driveway access. 20. All public utility services serving this property shall be placed underground. 21. Two copies of an erosion and sediment control plan shall be submitted for review and approval by the Engineering Department prior to acceptance Staff Report to the Planning Commission Lands of Goese 13480 Wildcrest Drive July 14, 2005 Page 13 of 14 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. The first 100 feet of the driveway shall be rocked during construction and all cut and fill slopes shall be protected from erosion. 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. 22. 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, clean-up area, 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. 23. 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 photographs of the existing conditions of the roadways and pathways prior to acceptance of plans for building plan check. 24. The driveway shall be required to be fully constructed and to be roughened where the pathway intersects, to the satisfaction of the City Engineer, prior to final inspection. 25. The property owner shall be required to connect to the public sanitary sewer prior to final inspection. A sewer plan that is prepared by a registered civil engineer shall be required to be approved by the City Engineer prior to submittal of plans for building plan check. A copy of a recorded private sanitary sewer easement of the neighbor property shall be required to be submitted to the Town prior to submittal of plans for building plan check A sewer hook-up permit shall be obtained from the Town prior to submittal of plans for building permit plan check. Staff Report to the Planning Commission Lands of Co se 13480 W ildcrest Drive July 14, 2005 Page 14 of 14 26. The property owner shall pay a pathway fee of $46.00 per linear foot of the average width of the property prior to acceptance of plans for building plan check. C. FIRE DEPARTMENT: 27. An automatic residential fire sprinkler system approved by the Santa Clara County Fire Department shall be included in the new residence. Three copies of plans prepared by a sprinkler contractor shall be submitted to the Planning Department and approved by the Fire Department, prior to acceptance of plans for building plan check, and the sprinklers shall be inspected and approved by the Fire Department, prior to final inspection. 28. 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 taming radius of 36' outside and 23' inside, and a maximum slope of 15%. 29. The property address shall be placed on the main residence so that it is clearly visible and legible from the street or road fronting the property. The address numbers shall be a minimum of four inches high and shall contrast with the background color. CONDITION NUMBERS 5,12,17A, 17B, 18,21, 22, 23, 25, 26 AND 27 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 August 6, 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 pemdt is valid for one year from the approval date (until July 14, 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. ATTACHMENTcZ O LA PALO" r e -PMD. f i � Y / N x _. PRL LOTF 17 PTN. LOT 1 L° _ 1 q�Y R se r its 040 f x {� /1 • o =yam ��'•�.R09LEDA� \\� R sm ym ... y j g y 0g y 4c �4 �N�a- 0 tv� w c.9 0 EsE . 3 ENVIRONMENTAL DESIGN COMMITTEE ATTACHMENT NEW RESIDENCE EVALUATION RECEIVED Applicant's Name: cfl b F—SE ''"MAY 1 6 2005 Address: ) 34-ga a91 I Dc-R-� -r 1'agwg LOS ALTOS HILLS Reviewed by: Date: OS 1 ( 6 10S Existing Trees: (Comment on size, type, condition, location with respect to building site. Recommended protection during cons c on. 1r V 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 -54 Other Comments: GA«k 4)w .be,,4 COTTON, SHIRES & ASSOCIATES, INC. CONSULTING ENGINEERS AND GEOLOGISTS ATTACHMENT Y June 6, 2005 L0142A TO: Debbie Pedro RECEIVED Planning Department TOWN OF LOS ALTOS HILLS 26379 Fremont Road Los Altos Hills, California 94022 TOWN OF LASECENED� SUBJECT: Geologic and Geotechnical Peer Review RR RE: Goese, New Residence, Pool and Spa File M90-05-ZP-SD-GD JUN 07 2005 13480 Wildcrest Drive At your request, we have completed a geologic and geotechnIPWWWWW WS the application for proposed development using: • Geotechnical Investigation (report), prepared by Murray Engineers, Inc., dated April 18, 2005; • Civil Plans (8 sheets, 20 -scale), prepared by Sandis Humber Jones, dated April 29, 2005; and • Architectural Plans (5 sheets, 8- and 16 -scales), prepared by Brian David Peters, dated April 29, 2005. In addition, we reviewed pertinent technical documents from our office files and performed a recent site reconnaissance. DISCUSSION Our review of the referenced documents indicates that the applicant proposes to remove the existing residence and garage and construct a new two-story residence with a basement and garage. The applicant also proposes to partially re -align the existing driveway and construct a new section leading to a different portion of the property. A swimming pool is proposed on the southern portion of the building pad. Project grading includes an estimated 480 cubic yards of cut and 205 cubic yards of fill, with the excess material to be off -hauled from the site. In our previous letter Qune 18, 2002), we reviewed an earlier development plan and concluded it was geotechnically feasible. For our current review, we have received an updated set of plans and an additional geotechnical report. The property is located along the crest of an east—west trending ridgeline that terminates to the east. Slopes are characterized as moderately steep to steep (20 to 40 percent inclination), with flanking north- and south -facing slopes of similar inclination. The proposed construction site is located on the existing, relatively level cut and fill pad, bounded to the north and south by steep to very steep (30 to 85 percent inclination) fill slopes and to the west by a precipitous cut slope (100 to 150 percent inclination). The Northern California Office Southern California Office 330 Village Lane 5245 Avenida Encinas • Suite A Los Gatos, CA 95030-7218 Carlsbad, CA 92008-4374 (408)354-5542 • Fax (408) 354-1852 (760) 931-2700 • Fax: (760) 931-1020 e-mail: losgatos®cottonshires.com www.cottonshires.com e-mail: Carlsbad®cottonshires.com Debbie Pedro June 6, 2005 Page 2 L0142A existing residence appears to be located on shallow fill materials (to a maximum depth of approximately 5 feet) placed on colluvium and bedrock Drainage at the site is generally characterized by uncontrolled sheetflow off the ridgeline to the north, east and south. The Town Geotechnical Map indicates that the subject property is underlain, at depth, by bedrock materials of Santa Clara Formation (semi -consolidated siltstone, sandstone, and potentially expansive claystone). The bedrock is overlain by potentially expansive silty to sandy clay (colluvium and existing fill). During our site reconnaissance, we observed extensive cracking to the driveway and parking area on the north side of the site, and cracks to the patio slab on the south side of the site. The patio slab also appears to have pulled away from the residence. This indicates likely settlement and creep of existing colluvium and artificial fill materials. The site is located approximately 0.5 mile north of the Monta Vista fault, 1.0 mile north of the Altamont fault, and 3.8 miles northeast of the San Andreas fault. CONCLUSIONS AND RECOMMENDED ACTION The proposed construction is constrained by the proximity to steep slopes, instability of existing site colluvial soils and non -engineered fill materials, potentially expansive earth materials, and susceptibility to strong seismic ground shaking. In our opinion, the proposed development is geotechnically feasible with utilization of appropriate geotechnical design parameters. The Project Geotechnical Consultant has completed an investigation of the site and provided geotechnical design criteria that, in general, appear appropriate for the apparent site constraints. The recommendations include, founding non -basement portions of the proposed residence, retaining walls, and pool on minimum 18 -inch -diameter piers embedded a minimum of 10 feet into bedrock, founding the basement on a minim= 10 -inch -thick mat foundation, and replacing existing unstable artificial fill materials with appropriately engineered fill that is keyed and benched into bedrock. Consequently, we recommend the following conditions be satisfactorily completed as a condition of application approval. 1. 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 along with documents for building permit plan -check. 2. 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. In addition, the consultant should examine bedrock structure and encountered bedrock units during site excavation and COTTON, SHIRES & ASSOCIATES, INC. Debbie Pedro June 6, 2005 Page L0142A pier drilling. If significant claystone is encountered, then supplemental testing to address the expansion potential of the claystone should be performed. 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 (granting of occupancy) 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. POS:TS:RR:st Respectfully submitted, COTTON, SHIRES AND ASSOCIATES, INC. TOWN GEOTECHNICAL CONSULTANT Ted & Senior Geologist - Tatcick O. Shires Principal Geotechnical Engineer GE 770 COTTON, SHIRES & ASSOCIATES, INC. cotMAEC. UFC Apppendix IIIA UFC 1003.1.2 as k.vndedby LAHMC 8-8.0.1 UFC 902.2.4.1 SHEET FIRr, DEPARTMENT SANTA CLARA COUNTY 14700 Winchester Blvd., Los Gatos, CA 95032-1818 (408) 378-4010 • (408) 378-9342 (fax) •..scdd.org PIAN REVIEW NUMBER O?ECW BLDGPERMRNUMBEB jPMf APMEW CONINOLNUMF0VVN.OF 10n4 ALJ05 NILS FUE NUMBER 90-05-ZP-SD-GD DEVELOPMENT REVIEW COMMENTS REOUREMEM Review of site plan for 7,128 square foot single family residence with an attached garage. Comment on sheet G1 reflecting intent to fully sprinkler all portions of the building is duly noted. Review of this Developmental proposal is limited to acceptability of site access and water supply as they pertain to fire department operations, and shall not be construed as a substitute for formal plan review to determine compliance with adopted model codes. Prior to performing any work the applicant shall make application to, and receive from, the Building Department all applicable construction permits. Required Fire Flow: The fire flow for this project is 2250 gpm at 20 psi residual pressure. As an automatic fire sprinkler system will be installed, the fire flow has been reduced by 75% establishing a required adjusted fire flow of 1000 gpm at 20 psi residual pressure. The adjusted fire flow is not available from area water mains and fire hydrant(s) which are spaced at the required spacing. 2. Automatic Fire Sprinkler System Required: Buildings requiring a fire flow in excess of 2,000 GPM shall be protected throughout by an approved, automatic fire sprinkler system, hydraulically designed per National Fire Protection Association (NFPA) Standard #13d and standard & detail SP4 of this department. paratus (Engine)Access Driveway Required: Provide an access driveway raved all weather surface, a minimum unobstructed width of 14 feet, clearance of 13 feet 6 inches, minimum circulating turning radius of 36 feet and 23 feet inside, and a maximum slope of 15%. Installations shall 1 to Fire Department Standard Details and Specifications sheet D-1. C" PLANS SPECS NEW NMOL AS OCCUPNILY CONST.IPE APPINgN M DAME PAOE LAH ❑ ❑ ❑ ❑ ❑ BRIAN DAVID PETERS 5/5/200.5 1 2 OF SECJFLOON AIEL LOAD OESCPoPIION BV Residential Development Rucker, Ryan NAME OF PRQIECMWCATION SFR- GOESE 13480 Wildcrest Dr Organized as the Santa Clara County Central Fire Protection District heroin, Santa Clara County and the wmmunities of Campbell, Cupertino, Los Altos, Los Altos Hills, Los Gotos, Monte Sereno, Morgan Hill, and Saratoga (-e eOGFIRE :OOE/SEC. SHEET C ARendu C 1.3 C :.4.4 FIRr. DEPARTMENT PLAMRENIEWNUMBU 05 1378 SANTA CLARA COUNTY BLDG PERMR NUMBER 14700 Winchester Blvd., Los Gatos, CA 95032-1818 (408) 3784010 • (408) 378-9342 (fax) • Lvww.sccfd.org CONTROLNUMBER PRE NUMBER 90-05-ZP-SD-GU DEVELOPMENT REVIEW COMMENTS NO.I REQUIREMENT 4. Fire Department (Engine) Driveway Turn -around Required: Provide an approved fire department engine driveway turnaround with a minimum radius of 36 feet outside and 23 feet inside. Installations shall conform with Fire Department Standard Details and Specifications D-1. Revise turnaround to comply with standard specification D -1. 6. of Required Driveway Installations: Required driveway installations constructed and accepted by the Fire Department, prior to the start of ises Identification: Approved numbers or addresses shall be placed on all and existing buildings in such a position as to be plainly visible and legible the street or road fronting the property. Numbers shall contrast with their CDN P S SPECS NEW RMDL AS OCCUPP CONSr. TTPE AWI.Ma- DATE BE `H ❑ ❑ ❑ ❑ ❑ BRIAN DAVID PETERS 5/5/2005 2 2 OF hLODR MFd LOLO DESCRIpIpN gy Residential Development Rucker, Ryan ME OF PROJECT LOCATOR SFR- GOESE 113480 Wildcrest Dr urganizect as tne aanta Clara county central tire vrotecnon ulstnct Seming Santa Clam County and the oammunities of Campbell, Cupertino, Los Altos, Las Altos Hills, Los Gatos, Monte Sereno, Moyan Hill, and Saratoga 11/96;2002 13:42 6508514939 ART ELERETT PAGE 04 TOWN ON LOS ALTOS HILLS pTTACHMENT� PLA"iNO DEPARTMENT 76379 Fremont Road • Los Altos Hills, C:elifomia 94022 • (650) 941.7221 • PAX (650) 941.3160 WORKSHEET #2 EXISTING AND PROPOSED DEVELOPMENT AREA AND FLOOR AREA • TURN IN WITH YOUR APPLICATION PROPERTY OWNER'S NAME �r• YS. ZYs avl PROPERTY ADDRESS 1SO ,Wtl CY¢5 �/. �•G-. __^__ CALCULATED BY Y\/�.� SYAba✓ 7m�¢S 1 DATE 4129l0S 1. DEVELOPMENT AREA Existing (SQUARE FOOTAGE) , A. Houseand GWage(&om Pan2.A.) 4614 (p41q(0q(q ✓ B. Decking i-&- IQ, -61 Proposed Total (Additlon,/Dde iia ,) C. Driveway and Parking Ist Floor b. 2nd Floor (Measured 10. O'slang centerline) Attic and Basement d. D. Patios and Walkways1�SQ a. 8 E. Tennis Cour c. 6t F. Pool and Decking G. Accessory Buildings (from Pert B) H. Any other covCfage ?on. fp-(• TOTALS �sL la, boo Maximum Development Area Allowed - MDA ($om Worksheet #I) 2. TOTAL IMPERVIOUS SURFACE'. Existing (SQUARE FOOTAGE) TOTALS 1i�{53 3. FLOOR AREA tSQUARE FOOTAGE) Existing A. House and Garage a. Ist Floor b. 2nd Floor c. Attic and Basement d. Garage B. Accessory Buildings a. l st Floor b, 2nd Floor c. Attic and Basement Maximum Floor Area Allowed Proposed 2'314(0 88a 'bt Sly ✓ Ei40 f0,$6S 1_�9ss 1 11.0149 1 Total 10,1 65- I(J�B6S Proposed Total (AddltlonNDelrtienr) TOTALSMFA (from (from WoKsheet #1) U ZS 2 W13