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HomeMy WebLinkAbout3.5 + 3w S TOWN OF LOS ALTOS HILLS January 14, 1998 Staff Report to the Planning Commission RE: SITE DEVELOPMENT PERMIT FOR A NEW RESIDENCE AND POOL AND VARIANCE TO ALLOW GRADING OVER A PROPERTY LINE; LANDS OF WYTHE &VITU; 13824 MOON LANE(PARCEL 3); FILE#47-96-ZP-SD-GD. FROM: Suzanne Davis, Planner SD APPROVED BY: Curtis S. Williams,Planning Director RECOMMENDATION That the Planning Commission: 1. Make the findings as required by section 10-1.1107(2) of the Zoning Ordinance for the granting of a variance and approve the site development permit for the new residence and pool, subject to the recommended conditions; OR 2. Make the findings as required by section 10-1.1107(2) of the Zoning Ordinance for the granting of a variance and direct the applicants to make design changes to the house and/or pool area, working with staff to achieve the requested plan revisions, subject to the recommended conditions, modifying condition #1 accordingly; OR 3. Continue the application to February 11, 1998 and direct the applicants to redesign the residence to eliminate or reduce the basement, eliminate the pool and/or reduce the floor area to bring the project as close as possible to the Town's Grading Policy. BACKGROUND This proposal for a new residence and pool is the companion application to a proposed residence for the adjacent lot to the west. A complete background is contained in the staff report for parcel 2 at 13826 Moon Lane. The minutes from the two Planning Commission meetings and one Council meeting where discussion on the project took place are attached to the report for parcel 2. Several development restrictions were placed on parcel 3 as conditions of the subdivision that created the lot. The new residence may not exceed the 370 foot contour line in elevation. The condition also states that development shall be designed to minimize disturbance to the natural topography, and that the houses shall be stepped down or set into the sites. Due to steep topography and a conservation easement over a drainage course, the maximum floor and development areas may not be able to be achieved. The subdivision also required a single access to parcels 2 and 3 from Moon Lane. Two letters have been received from neighbors, and are attachments 8 and 9 to the staff report for parcel 2. Neighborhood concerns are the same as those indicated for parcel 2: the size and height of the houses, compatibility with existing homes on Moon Lane, grading volumes, retaining walls, and whether the sites can accommodate the proposed amount of development. Planning Commission January 14,1997 Lands of Wythe&Vitu(Parcel 3) Page 2 CODE REQUIREMENTS As required by Section 10-2.301 of the Site Development Ordinance, this application for a new residence has been forwarded to the Planning Commission for review and approval. Criteria for review from the Site Development Ordinance include grading, drainage, building siting, pathways, landscape screening and outdoor lighting. Zoning Code review encompasses compliance with floor and development area requirements, setbacks, height and parking. The granting of a variance requires four findings to be made,pursuant to Section 10-1.1107(2) of the Zoning Ordinance. DISCUSSION Site Data Gross Lot Area: 1.62 acres Net Lot Area: 1.58 acres Average Slope: 25.1% Lot Unit Factor: 1.07 Floor and Development Area Area Maximum Proposed Existing Increase Left Development 9,999 9,168 -0- +9,168 +831 Floor 5,613 4,900* -0- +4,900 +713 *excludes 950 square foot basement that is completely underground Site and Architecture The applicants are requesting approval of a site development permit to construct a new 4,200 square foot stepped one-story residence with an attached 700 square foot three-car garage and a 950 square foot basement. A small swimming pool and spa are also proposed. The second story has been eliminated and the building now steps down the slope. The house size (including garage) was reduced from 5,587 to 4,900 square feet. The total development area has increased slightly from 9,125 to 9,168 square feet due to the addition of a small pool. Although a basement has been added to the plans, it is not counted as floor or development area since it underground, and does not affect the above ground bulk and mass of the structure. Proposed exterior materials include a mixture of vertical wood and stucco siding, stone veneer accent, brick chimneys and flat tile roofing (resembles shake). The rear and left side (east) elevation have stucco siding, and the front and right side (west) have wood siding. The Design Guidelines state that a mixture of materials can create interest and detail, and that wood and stone can help soften the appearance of stucco and blend it with the natural setting. The exterior colors can also help blend the house into the site. The house has been stepped in four sections. The main living area would be 51/2 feet lower than the master bedroom wing. The secondary bedrooms step up 2'/2 feet from there with the garage 10 feet below. Rounded and bay elements, a mix of exterior materials, architectural detailing, varied roof lines and wall planes have been proposed to break up the massing of the building. Planning Commission January 14,1997 Lands of Wythe&Vitu(Parcel 3) Page 3 The maximum height of the new residence would be 24 feet from the finished grade, and 26 feet as measured from the lowest to highest point. The roof line generally steps with the hillside, although it may be able to be lowered in some areas if the Commission so desires. No skylights are proposed. The house would not be above the 370 foot elevation as required by the subdivision conditions. There would be 741 square feet of the floor area and 831 square feet of development area remaining for future projects as recommended by the Design Guidelines. However, due to steep slopes, setbacks, and a conservation easement on the site, it is unlikely that all of the allowable development area could be used. Driveway and Parking The garage entry has been oriented away from the street as recommended by the Design Guidelines. The garage entry will face the garage of the house on parcel 2. There is adequate space between the two backup areas for a landscape buffer. Part of the garage backup area encroaches into the side setback. The pavement would be about 18 feet from the property line at the closest point. This is the same driveway design as the original submittal. There were not any concerns stated about this design at previous Commission or Council hearings. The garage orientation for the two lots is the best approach given the requirement for a shared driveway. A reciprocal driveway easement will be required since the driveway will be partially on both properties until it splits to the separate garages, and part of the common driveway will serve as backup. The three spaces in the garage and one uncovered space meet the Zoning Ordinance requirement for four on-site parking spaces. The City Council discussed the condition and width of Moon Lane at its June 4, 1997 meeting and stated that the road should be widened and improved to facilitate emergency access and to meet minimum Fire and Engineering Department standards. Condition#21 requires the road improvement design to be approved by the City Engineer and the Fire Department, and the work to be completed prior to acceptance of plans for building plan check. This conditions is attached to development of both parcels. Improvements would include widening Moon Lane from Page Mill Road to the shared driveway, exclusive of the bridge crossing, and a new asphalt overlay. The road would be widened to 14 feet and would have turnouts. Trees &Landscaping There are no trees or substantial landscaping on the property. Landscape screening will be an important element of the project. Conceptual planting has been shown on sheet 1 of the development plans. The landscape plan will be reviewed at a site development hearing once the house is framed (see condition #2). This will allow for noticing of the neighbors, and better evaluation of where screening is needed. The Environmental Design & Protection Committee previously commented that the Incense Cedars on the property should be saved, which is the applicants' intent. The Committee recommended riparian planting in the conservation easement. This provision is included in condition #2. The Committee also pointed on the need for tall trees on the sides of the house, and the importance of exterior colors. Evergreen trees, such as redwoods and oaks, were suggested for screening. The standard color condition has been included, requiring compliance with the Town's adopted color board. As noted in the Design Guidelines, darker ornatural colors blend with surroundings, and roof colors should be darker with a variety of shades. Planning Commission January 14,1997 Lands of Wythe&Vitu(Parcel 3) Page 4 Lighting Proposed exterior lighting locations have been shown on the floor plans. Lighting has been limited to one fixture per exit. Staff will review the lighting specifications prior to acceptance of plans for building plan check (condition #8). Landscape lighting will be reviewed with the landscape plan. No skylights are proposed, but if the applicants decide to add any, no lights would be allowed within the skylight wells, and the glass would not be allowed to be clear in order to reduce emitted light. Grading&Drainage The Engineering Department has reviewed the preliminary grading and drainage plan, and has recommended conditions of approval included in Attachment 1. Proposed grading is 2,910 cubic yards of cut and 25 cubic yards of fill. Most of the grading is being done to set the house into the hillside and for excavation of the basement. Recontouring behind the house is being done for geotechnical stability of the slope above. Grading for the driveway would cross the common property line between parcels 2 and 3. This is not considered a variance since it is necessary to construct a required shared driveway. Proposed grading across the property line behind the proposed residences on parcels 2 and 3 does require a variance. There are some areas where the proposed residence and pool do not meet the Town's grading policy. These areas are as follows (grading policy maximum is in parenthesis): • The main level finished floor is five feet above the natural grade (three feet) • House cut is up to 111/2 feet(20' feet for basement) (eight feet excluding basement) • Cut for the patio behind the house is up to 13 feet(four feet) • Cut for the garage is up to 15 feet(eight feet) • Retaining walls behind the house up to 12 feet(three to four feet) The site is very steep and it is unlikely that the grading policy can be absolutely met. As discussed in the report for parcel 2, staff is concerned that the total amount and extent of excavation is substantial, particularly where cuts of up to 201/2 feet are proposed for the basement. Raising the house while minimizing the cut would make the house more visible from off the site. Eliminating the basement or reducing it substantially would lessen the grading and the amount of material to be exported from the site. If the pool were eliminated the length of the retaining wall along the east side of the house would be reduced and grading would be reduced. More strict compliance with the grading policy would require more substantive changes, such as increasing the garage elevation to 335.0 and deleting the floor area above it, or lowering or pulling the front of the house back to the 330 foot contour to reduce the main level. If the Commission desires such extensive modifications, staff suggests language similar to that provided in recommendation#3. Drainage is shown to be partially piped and partially sheet flow, with water being directed around the house, down the slope towards the swale that runs through the property below Moon Lane. Water from the upper slope and the back of the house would be collected by a series of catch basins, with a pipe daylighting on the lower slope below the house. An energy dissipater at the pipe outlet would slow the water and help prevent erosion. The swale has been engineered to handle the drainage from the proposed project. A final site grading and drainage plan will be reviewed and approved by the Engineering Department, prior to acceptance of plans for building plan check. The final Planning Commission January 14,1997 Lands of Wythe&Vita(Parcel S) Page 5 drainage and grading will be inspected by the Engineering Department, and any deficiencies will be required to be corrected prior to final inspection. The property will be connected to the public sanitary sewer prior to final inspection. Variance To grant a variance the Planning Commission must make four findings, as required by Section 10-1.1107(2) of the Zoning Ordinance. The most important of these findings requires specification of unusual or unique characteristics of the property that support exceptions to the provisions of the Code. In this case, the grading and re-contouring that is proposed to set the two houses into the hillside would create a hump between the two lots if the grading were not carried through between the two properties. The slope would look more natural if the grading is allowed. None of the neighbors should be adversely impacted since the grading would be done between the two home sites, and would not be close to any neighboring homes. Attachment 2 outlines the recommended findings for the proposed variances. If the Commission cannot make one or more of the findings, the variance should be denied. Geotechnical Review The Town geotechnical consultant, Cotton, Shires & Associates, has reviewed the revised plans and geotechnical report (see Attachment 3). Condition #12 includes the recommendations of the Town Geologist. Fire Department Review The Santa Clara County Fire Department requested that an on-site hydrant or a residential fire sprinkler system be provided since portions of the house would be greater than 150 feet from the existing hydrant. The Fire Department also requested that the property address be placed in a location that is clearly visible from the street and that the driveway meet minimum standards for fire access (see Attachment 3 to the staff report for parcel 2). The Fire Department recommendations have been included with the conditions of approval. Committee Review The Pathways Committee has no request for the property. Pathway improvements were part of the subdivision, and a pathway fee is not required. The Environmental Design & Protection Committee comments were discussed previously in this report. Staff is available to answer any questions that the Commission or the public may have. Planning Commission January 14,1997 Lands of Wythe&Vitu(Parcel 3) Page 6 ATTACHMENTS 1. Recommended conditions of approval 2. Recommended findings for the granting of a variance 3. Letter from Cotton, Shires &Associates, dated January 7, 1998 (three pages) 4. Worksheet#2 5. Development plans: site, floor & roof plans, building sections, and elevations and conceptual landscape plan(three sheets) cc: Evan Wythe &Janet Vitu 13826 Page Mill Road Los Altos Hills, CA 94022 Susan Roberts Giuliani &Kull • 20431 Stevens Creek Boulevard, Suite 230 Cupertino, CA 95014 Glenn Cahoon G& G Design 445 S. San Antonio Road, Suite 103 Los Altos, CA 94022 ATTACHMENT 1 RECOMMENDED CONDITIONS FOR SITE DEVELOPMENT PERMIT FOR NEW RESIDENCE, POOL & SPA LANDS OF WYTHE &VITU- 13824 MOON LANE (PARCEL 3) A. PLANNING DEPARTMENT: 1. The basement exiting and window wells shall be the minimum required by the Uniform Building Code, and the entire basement shall be below the adjacent finished grade. Plans demonstrating conformance shall be submitted for approval by the Planning Department,prior to acceptance of plans for building plan check Any changes or modifications to the approved plans shall be approved by the Planning Director or the Planning Commission, depending upon the scope of the changes. 2. Subsequent to final framing, a landscape screening and erosion control plan shall be reviewed by the Site Development Committee. Consideration shall be given to views from neighbors homes, and use of evergreen, native species such as oaks and redwoods is recommended. Planting within the storm drain and conservation easements shall be native, riparian species. All landscaping required for screening purposes or for erosion control (as determined by the City Engineer) must be installed prior to final inspection, unless the Planning Director finds that unusual circumstances, such as weather or site conditions, require that planting be delayed. In those instances, a deposit of an amount equal to the cost of landscape materials and installation, to the satisfaction of the Planning Director, shall be submitted to the Town. Landscaping shall in any event be installed not later than six months after final inspection, or the deposit will be forfeited. 3. A landscape maintenance deposit (or certificate of deposit), equal to the cost of materials and installation for all landscaping required for screening purposes or for erosion control (as determined by the City Engineer), but not to exceed $5,000.00, shall be posted prior to final inspection. An inspection of the landscape to ensure adequate establishment and maintenance shall be made two years after installation. The deposit will be released at that time if the plantings remain viable. 4. If any equipment will be accessing the site in the vicinity of the juniper tree near Moon Lane, the tree shall be fenced at the dripline prior to commencement of any grading or construction. The fencing shall be of a material and structure to clearly delineate the dripline. Town staff must inspect the fencing prior to issuance of any building permits. The fencing must remain throughout the course of construction. No storage of equipment, vehicles or debris shall be allowed within the driplines of fenced trees. 5. Fire retardant roofing is required for the new construction. 6. Paint colors shall be chosen by the applicant and approved by staff in conformance with the Town's adopted color board, and shall exhibit a light reflectivity value of 50 or less. Roofs shall use materials which have a light reflectivity value of 40 or less. White trim area should be Recommended Conditions . Lands of Wythe&Vitt'(Parcel 3) Page 8 minimized, particularly on large surfaces such as doors, columns, railings, and trellises. A color 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. 7. Skylights, if utilized, shall be designed and constructed to reduce emitted light. No lighting may be placed within skylight wells. 8. Lighting specifications for outdoor lighting fixtures on the house shall be submitted for Planning Department approval prior to acceptance of plans for building plan check. 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. No lighting may be placed within setbacks except for two driveway or entry lights. Any light fixtures that are visible from the roadways shall be down shielded fixtures or shall have opaque glass. Any other outdoor lighting shall be reviewed with the landscape plan at a Site Development Hearing. 9. At the time of foundation inspection(s), the location, and elevation of the new residence shall be certified in writing by a registered civil engineer or licensed land surveyor as being in/at the approved locations and elevations shown on the approved site development plan. At the time of framing, the height of the structure shall be similarly certified as being at the height shown on the approved site development plan. The hardscape, driveway and pool locations shall also be certified at time of installation. 10. Standard swimming pool requirements: a. Lights shall be designed iso that the source is not visible from off-site. b. Drainage outfall structures shall be constructed and located to the satisfaction of the Town Engineering Inspector. c. Fencing or a locking pool cover is recommended for safety. d. Equipment shall be enclosed on all four sides for noise mitigation, and the enclosure shall be screened with landscaping. The equipment enclosure shall not encroach into any setbacks. B. ENGINEERING DEPARTMENT: 11. As recommended by Cotton, Shires & Associates in their report dated January 7, 1998,the applicant shall comply with the following: a. The project geotechnical consultant shall review and approve all geotechnical aspects of the project including minimum pier reinforcement, and shall summarize the results of their plan review in a letter to be submitted to the e Town, prior to acceptance of plans for building plan check. b. The project geotechnical consultant shall describe the results of inspections and as-built conditions of the project in a letter to be submitted to the Town Engineering Department prior to final inspection. Recommended Conditions Lands of Wythe&Vitu(Parcel 3) Page 9 For further details on the above requirements, please reference the letter from Cotton, Shires &Associates dated January 7, 1998. 12. A final site grading and drainage plan shall be required to be approved 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. 13. 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. 14. All public utility services serving this property shall be placed underground. 15. 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. 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. 16. 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 plan shall address truck traffic issues regarding dust, noise, and vehicular and pedestrian traffic safety on Moon Lane 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. 17. The driveway shall be required to be fully constructed, to the satisfaction of the City Engineer,prior to fmal inspection. 18. 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 Recommended Conditions Lands of Wythe&Vita(Parcel 3) Page 10 of the existing conditions of the roadways and pathways, prior to acceptance of plans for building plan check. 19. The property owner shall obtain an additional driveway easement from the property owner of Parcel 3, and shall submit a copy of the recorded document to the Town, prior to acceptance of plans for building plan check. The driveway shall be fully constructed to the satisfaction of the City Engineer,prior to final inspection. 20. The property shall be connected to the public sanitary sewer, prior to final inspection. 21. Moon Lane shall be widened to a minimum of 14 feet with turnouts provided, from Page Mill Road to the shared driveway to the project site, exclusive of the bridge crossing. Lower Moon lane shall have an asphalt overlay from the access driveway to Page Mill Road. The design shall be approved by the City Engineer and Santa Clara County Fire Department and the work shall be completed to the satisfaction of the City Engineer, prior to acceptance of plans for building plan check. C. FIRE DEPARTMENT 22. The property address shall be placed so that it is clearly visibleand legible from Moon Lane. Numbers shall contrast with the background and shall be a minimum of four inches high. 23. The driveway shall be a minimum of 14 feet wide and shall have an unobstructed vertical clearance of 13 feet six inches. The driveway shall have an all weather surface that is designed and maintained to support the imposed loads of fire apparatus (40,000 pounds) and the gradient shall not exceed 17%. 24. The driveway shown on the site development plan in combination with the driveway for parcel 2 is adequate for turning around emergency vehicles. Any changes to the driveway design(s) shall first be approved by the Santa Clara County Fire Department and the Town Engineering and Planning Departments. 25. Unless otherwise determined by the Santa Clara County Fire Department, an automatic residential fire sprinkler system approved by the Fire Department shall be included in the new residence. The details of the sprinkler system shall be included with construction plans. The plans shall be stamped and signed by the Fire Department and submitted to the Town, 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. The applicant may propose alternate means of achieving an acceptable water supply instead of fire sprinklers, such as installation of an on-site fire hydrant, subject to the approval of the Fire Department. 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. Recommended Conditions - Lands of Wythe&Vitu(Parcel 3) Page 11 CONDITION NUMBERS 1, 6, 8, 11a, 12, 15, 16, 18, 19, AND 24 SHALL BE COMPLETED AND SIGNED OFF BY THE PLANNING AND ENGINEERING DEPARTMENTS PRIOR TO ACCEPTANCE OF CONSTRUCTION PLANS FOR PLAN CHECK BY THE BUILDING DEPT. Protective tree fencing shall be inspected and approved by the Planning Department,prior to issuance of any building permits. Properties residing within the Los Altos or Palo Alto School District boundaries must pay School District fees before receiving their building permit from Los Altos Hills. The applicant must take a copy of Worksheet #2 to the school district office(s), pay the appropriate fees, and provide the Town with a copy of their receipts. NOTE: The Site Development permit is valid for one year from the approval date (until January 14, 1999). 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 THE GRANTING OF A VARIANCE TO ALLOW GRADING WITHIN 10 FEET OF AND ACROSS A PROPERTY LINE LANDS OF WYTHE&VITU- 13824 MOON LANE (PARCEL 3) 1. 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. The property has a relatively steep slope, and the location of the new residence is established by the minimum building setbacks, the requirements that the 370 foot elevation not be exceeded and that the house be stepped or set into the slope, and the presence of a conservation easement. The two lots are being developed concurrently, and a common driveway was required along the joint property line. Also, the grading behind the houses has been designed to address geotechnical concerns on slope stabilization. These constraints require a large amount of grading to be done, and if the grading over the property line were not allowed, an unnatural cut hill would be created between the two properties, which would be an undesirable topographic feature. The granting of the variance will allow the property owners to have a more natural slope similar to that on other properties in the surrounding neighborhood. A strict application of the zoning standards would deprive the subject property of a privilege enjoyed by other properties in the vicinity and in the same zoning district(more natural grading). 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 The intent and purpose of the Zoning Ordinance will still be served because the grading to be done across the property line will be confined to a relatively small area between parcels 2 and 3, which will be developed concurrently. The remainder of the grading for the project will not encroach into the 10 foot area along property lines. The site is unusual in that there are strict conditions placed on the property by the subdivision approval. The 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. 3. The granting of such variance will not be materially detrimental to the public welfare or injurious to the property, improvements or uses within the immediate vicinity and within the same zoning district. The house will be constructed to meet all imposed development restrictions and will be set into the hillside, and the project meets or has been conditioned to meet all other applicable Town codes and policies. Grading across the property line will allow a more natural topographic transition between parcels 2 and 3, and will not adversely affect any neighboring properties. The proposed plan is sensitive to the character of the land,the surroundings and the Town's codes and policies. Recommended Variance Findings Lands of Wythe&Vitu(Parcel 3) Page 13 4. The variance will not authorize a use or activity which is not otherwise expressly authorized by the Zoning District regulations governing the parcel of property. The proposed single family residence is a permitted use in the R-A zoning district, and grading between this property and the adjacent parcel 3 would not allow a use or activity that is prohibited in the zoning district. f-v{ 1 COTTON,ra SHIRES & ASSOCIATES, RECEIVED INC. CONSULTING ENGINEERS AND GEOLOGISTS JAN - 8 1998 Janu OWNryMEE thS ALTOS HILLS L3186B TO: Suzanne Davis Planner TOWN OF LOS ALTOS HILLS 26379 Fremont Road Los Altos Hills,California 94022 SUBJECT: Supplemental Geotechnical Review RE: Lands of Wythe/Vitus New Residence File#47-96-ZP-SD-GD Moon Lane (Parcel 3) At your request, we have completed a supplemental geotechnical review of application for site development using: • Revised Site Development Plan (1 sheet, 20-scale) prepared by Giuliani and Kull,dated December 26, 1997; and • Improvement Plans Review (letter) prepared by Earth Systems Consultants, dated November 18, 1997. DISCUSSION The applicant proposes to construct a single-family residence and driveway on the subject property. Proposed site grading includes 2,910 cubic yards of excavation and 25 cubic yards of fill placement. In our previous review memorandum (dated April 8, 1997) regarding the subject property, we evaluated a previous site development plan dated June 14, 1996. We concurred with the Project Geotechnical Consultant that the proposed site development was geologically feasible. CONCLUSIONS AND RECOMMENDED ACTION We do not have geotechnical objections to the basic, currently proposed site development concept. However, we note that the latest development plan has 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:losg@csageo.com e-mail:carl@csageo.com Suzanne Davis January 7, 1998 Page 2 L3186B apparently not been formally reviewed by the Project Geotechnical Consultant. In addition, it is not clear where the supplied concrete swale detail is to be implemented in the project design. As a minimum, we assume a concrete swale (V-ditch) is to be constructed along the upslope side of retaining walls behind the residence. The current drainage plan also does not indicate how water collected by concrete swales will be conveyed to an appropriate discharge point, or how surface flow, which is intercepted along the upslope side of the two joining driveways, is to be properly controlled. We understand that final site drainage improvements are to be designed to the satisfaction of the Town Engineer. We recommend geotechnical approval of permits for project construction with the following conditions: 1. Geotechnical Plan Review - The applicant's geotechnical consultant shall review and approve all geotechnical aspects of the final project construction plans and supporting structural calculations (i.e., site preparation and grading, site drainage improvements and design parameters for retaining walls, foundations and driveway) to ensure that his recommendations have been properly incorporated. The consultant shall verify that steel reinforcement for foundation piers and grade beams meet minimum geotechnical criteria to address site soil conditions. 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. 2. Geotechnical Field Inspection -The geotechnical consultant shall 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 consultant shall inspect site excavations to verify anticipated subsurface conditions and observe the drilling of foundation piers to confirm satisfactory embedment into supporting materials. The results of these inspections and the as-built conditions of the project shall be described by the geotechnical consultant in a letter and submitted to the Town Engineer for review prior to final (as- built)project approval. This 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 COTTON, SHIRES & ASSOCIATES, INC. Suzanne Davis January 7, 1998 Page 3 L3186B 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 Ted Sayre Supervising Engineering Geologist CEG 1795 Patrick O.Shires Principal Geotechnical Engineer GE 770 POS:TS:rb COTTON, SHIRES & ASSOCIATES, INC. I 1 r4cHvt�Tc • TOWN OF LOS ALTOS HILLS PLANNING DEPARTMENT 26379 Fremont Road•Los Altos Hills,California 94022•(415)941-7222•FAX(415)941-3160 f2--.e_A/5.e_a WORKSHEET #2 EXISTING AND PROPOSED DEVELOPMENT AREA AND FLOOR AREA • TURN IN WITH YOUR APPLICATION • PROPERTY OWNER'S NAME I A 1y Q.- & V 1,- ,b PROPERTY ADDRESS ( 324- c)on La'w_ C Parcek. 3.) CALCULATED BY , & G DSS llA 1 E /� 1. DEVELOPMENT AREA (SQUARE FOOTAGE) l Existing Proposed Total (Additions or Deletions) A. House and Garage(from Part 2.A.) C.,c ) (.-Capp B. Decking C. Driveway and Parking • (Measured 100'along centerline) 2 5 I Qj 2- 12) D. Patios and Walkways I Off) t 0E0 E. Tennis Court F. Pool and Decking Oji] ;t1c) G. Accessory Buildings (from Part B) • H. Any other coverage TOTALS .c-- I Q-RD 916a Maximum Development Area Allowed-MDA(from Worksheet#1) 4999 2. FLOOR AREA (SQUARE FOOTAGE) Existing Proposed. Total (Additions or Deletions) A. House and Garage a. 1st Floor L4.2_ O 42-00 b. 2nd Floor c. Attic and Basement Cxx'P,rnp0 (. ) d. Garage r1 00 r/ CO B. Accessory Buildings a. 1st Floor b. 2nd Floor c. Attic and Basement TOTALS L.4-9Op (4900 r r Maximum Floor Area Allowed- MFA(from Worksheet#1) SP 13 TOWN USE ONLY CHECKED BY E i2an aVlS DATE j . 7i LOY6. Revised 2/26/96