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Home My WebLink AboutB14-0153_414151A ltr (05-21-14) Drain Plan_1400796060.pdf Herwrorth-Pan lak GeotechnicaI. Inc. P. O. Drawer 1887 GeS1-1 tech Sih•er[lusrne,Colorado 80498 Phone:970-468-i 989 HEPWORTH-PAWLAK GEOTECHNICAL Fax:970-468-5891 May 21,2014 email: hpgeo4@hrgeorech.com Mountain Air Builders LLC Attn: Mr.Roland Lee 1513 Birch Street Canon City, CO 81212 Job No. 414 151A Subj ect: Recommendations for an Underdrain System, Exterior Perimeter Drain, Underslab Drain, Sump Pump and Pit Recommendations, Renovation/Addition to the Hoyt-Young Residence, 2764 South Frontage Road,Town of Vail, Colorado. Dear Mr.Lee: As requested,Hepworth-Pawlak Geotechnical, Inc. (HP Geotech) is providing recommendations for an underdrain system for the subject project. Our services are provided in accordance with our agreement to Mountain Air Builders LLC dated May 15, 2014. We reviewed the architectural plans prepared by Martin Manley Architects,Project No. 1350, dated 04/18/14 and structural plans prepared by KRM Consultants,Inc.,Project No. 1401-09,dated 4/21/2014. Due to the potential for seasonal shallow groundwater, we recommend that the lower level be protected by an perimeter drain and underslab drainage system. PERIMETER DRAIN SYSTEM We recommend below grade foundation walls be protected by a exterior perimeter drain. A typical exterior drain detail is shown on the attached Figure I. An Exterior Perimeter and Underslab Drain Plan is shown on Figure 3. The exterior perimeter drain should consist of 4- inch,rigid,perforated SDR35 drain pipe placed in the bottom of a trench and backfilled with drain gravel no less than 12-inches in depth. The drain line should be placed at or below adjacent footing elevation and at least 12-inches below the lowest adjacent floor level and graded at a minimum of 1 percent. The gravel should be burrito-wrapped with filter fabric. At its lowest elevation the perimeter drain should connect to a 4-inch,rigid, solid SDR35 PVC pipe sloped under the footing at one percent to the sump pit located in the crawlspace. Free-draining granular material used in the drain system should consist of minus 2-inch aggregate with less than 50 percent passing the No. 4 sieve and less than 2 percent passing the No. 200 sieve. Filter fabric shall consist of Mirafi 140N, or equivalent. Glenwood Springs 970-945-7988 • Parker 303-841-7119 • Colorado Springs 719-633-5562 Mountain Air Builders LLC May 21,2014 Page 2 UNDERSLAB DRAIN SYSTEM The purpose of the underslab drainage system is to reduce the potential for a damp slab condition. The underslab drain system should consist of a minimum of 4-inches of drain gravel under the floor slab. One rigid perforated interior lateral drain should be placed with a minimum of 4- inches of drain gravel surrounding the lateral on all sides and sloped at one percent under the footing connecting to the exterior perimeter drain. The interior lateral should be 4-inch, perforated SDR35 drain pipe. Free-draining granular material used in the underslab drain system should consist of minus 2-inch aggregate with less than 50 percent passing the No. 4 sieve and less than 2 percent passing the No. 200 sieve. SUMP PIT We recommend a sump pit be located in the crawlspace at the lower level. The sump pit should be at least 30-inches in diameter and have at least 3 feet below the lowest inlet for collection of water. SUMP PUMP AND OUTLET PIPING We recommend the sump pump consist of a Zoeller Wastemate 267 with a variable float be used to remove water from the sump pit. The lower"off" float should be set to ensure the pump remains submerged for noise reduction and cooling. The upper"on" float shall be set 6 inches below the lowest pipe inlet. A high water alarm shall be implemented and set to 3 inches below the lowest pipe inlet. The discharge piping shall consist of 2 inch Schedule 40 PVC pipe. The use of hangers with rubber gasket fitting will help decrease vibrations and deaden the noise when the pump kicks on and off. We recommend the outlet piping be extended to discharge water to the southwest side of the proposed residence. The discharge outlet should expel water onto a concrete pan from the edge of the residence for a minimum of 4 feet. The discharge outlet shall be set high enough above the concrete pan as to not be blocked by freezing water. The use of splash blocks may be necessary. The concrete pan should be sloped at a minimum of 5 percent towards the creek. DAMPPROOFING For floor slabs bearing on drain gravel,we recommend vapor retarders conform to the minimum requirements of ASTM E1745 Class A material. For crawlspace floors, we recommend vapor retarders conform to the minimum requirements of ASTM El 745 Class C material. Concrete Job No. 414 151A Mach Mountain Air Builders LLC May 21,2014 Page 3 slabs are anticipated to bear directly on the vapor retarders. Concrete slabs bearing directly on vapor retarders should expect some curling that may affect the floor flatness. The use of reinforcement, see AC1 360R (0.5% gross concrete area), a low shrink concrete mix design, or an allowance for grinding and patching may be necessary. For exterior below grade foundation walls,we recommend dampproofing consist of bituminous material, 3 lbs per square yard, extending from the top of the footing to above ground level. CONTINUING SERVICES We recommend a representative of HP Geotech observe the foundation bearing soils prior to forming footings to determine if the exposed soils are compatible with our recommendations. A representative of HP Geotech should observe all aspects of the underslab drain system, exterior perimeter drain, sump pit and pump prior to backfilling at the time of construction to determine if our recommendations have been properly implemented. Please call if we can be of any further assistance. Sincerely, HEPWORTH-PAWLAK GEOTECHNICAL, INC_ ,,13900 tic . /..61 • MBR, ., • . 4 Chad M. Bringle,P.E. • , 11 I: � Project Engineer •. d S/Z t/ • • ss. 000000 ON,��N Attachments: Figure 1 —Typical Exterior Perimeter Drain Detail : Figure 2—Underslab Drain Detail Figure 3-Perimeter and Underslab Drain Plan Job No.414 l 5 l A Gggtech 1. DRAIN PIPE-consists of 4-inch, rigid, perforated SDR35 RELATIVELY IMPERVIOUS drain pipe, surrounded by a minimum of 4 inches of drain BACKFILL IN THE UPPER 2 gravel on the top and sides, sloped at 1 percent to a sump FEET OR FLATWORK/ pit where the water can be removed by pumping. Bottom of ASPHALT pipe at the high point should be a minimum of 12 inches below the top of the floor. BACKFILL SURFACE 2. DRAIN GRAVEL-consists of minus 2-inch aggregate with 10 PERCENT MINIMUM less than 50 percent passing the No.4 sieve and less than 2 SLOPE FOR LANDSCAPE percent passing the No. 200 sieve. Drain gravel should fill AREAS OR 3 PERCENT FOR the entire trench a be a minimum of 18 inches deep.The FLATWORK/ASPHALT FOR drain gravel under the slab should be connected to the 10 FEET perimeter drain system by means of 4-inch Schedule 40 `W., piping under the footing. 3.VAPOR RETARDER-consists of a retarder meeting the • ‘\ //, •/, i\ e minimum requirements of ASTM E1745 Class A material, • -o adequately overlaped and sealed. Vapor retarder should be • • installed in accordance with the manufacturers FOUNDATION WALL i specifications. A 4. FILTER FABRIC-burrito wrap drain gravel and drain pipe with Mirafi 140N, or equivalent. DAMPPROOFING °.,• e FILTER FABRIC E • ,• _�, e p. ' TOP OF SLAB �1 e • ..Da D v • o DRAIN GRAVEL i\1 ., .,�., ., .,•.; i tri.. i�..d iii.�ii ��i.. , ‘1419,4 4'311" , 111SOPAPVIA41/1. — I e / R J DRAIN PIPE -ft Or/ 1 VAPOR RETARDER 1 DRAIN GRAVEL NOT TO SCALE 414 151A Geaech 2764 SOUTH FRONATGE ROAD FIGURE 1 HEPWORTH-PAWLAKGEOTECHNICAL TYPICAL EXTERIOR PERIMETER DRAIN DETAIL 1. INTERIOR LATERAL Consist of 4-inch, perforated SDR35 drain pipe surrounded by a minimum of 4-inches of drain gravel with a minimum of 4-inches below pipe). Pipe invert should be placed a minimum of 8 inches below bottom of floor level(high point) sloped at 1%minimum to the sump pit. INTERIOR LATERAL 2. DRAIN GRAVEL DRAIN Consists of minus 2 inch aggregate with at least 50%retained on the No.4 sieve GRAVEL and less than 2%passing the No.200 sieve. Minimum 4 inches under floor VAPOR slab connected to sump pit below any RETARDER/ mitigation measures to prevent damp BARRIER slab(Vapor Retarder/Barrier).Slope to subgrade to sump at 1%. • FOUNDATION FOUNDATION : WALL 3.VAPOR RETARDER/BARRIER WALL Meeting ASTM E1745 Class A requirements. Installed in accordance • with manufacturers'recommendations. ;• O INTERIOR LATERALS SDR35 Drain Pipe Nominal Pipe Size: 4-inch Perforation Arrangement Hole Size: %-inch to Y2-inch Center-to-Center: 3-inch = 3/8 Rows of Holes: 2,90°-1 foot on center 90° X13" NOT TO SCALE 414 114AC-tee 5tecfl 2764 SOUTH FRONTAGE ROAD FIGURE 2 HEPWORTH-PAWLAK GEOTECHNICAL UNDERSLAB DRAIN DETAIL 11 101'-D- •_gy 7•_D• ,` 3._0. S2-1tj'2" 7-C ' 27'-8.. :