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Home My WebLink AboutSubsoils Report for Foundation DesignI (lA *i"ril['f,T?:$trn*rd' * * An Employcc Owncd Compony 5020 County Road 154 Glenu'ood Springs, CO 81601 phone: (970) 945-7988 fax: (970)945-8454 email : kaglenu'ood@kumarusa.com u,u'u,.kuntatusa.com Office Locations: Denver (HQ), Parker, Colorado Springs, Fort Collins. Glenwood Springs, and Surnmit County, Colorado SUBSOIL STUDY FOR FOUNDATION DESIGN PROPOSED RESIDENCE 19 ROAN CREEK PLACE LOT 26, BLOCK 2, FILING 1 BATTLEMENT CREEK VILLAGE GARFIELD COUNTY, COLORADO PROJECT NO. 25-7-245 MAY 29,2025 PREPARED FOR: TORREY & SONS, LLC ATTN: TORREY BYMAN 854 ANTLER POINT LANE stLT, coLoRADO 81652 torrev bvman@outlook.com { N \} It \ ._$ N TABLE OF CONTENTS PURPOSE AND SCOPE OF STUDY PROPOSED CONSTRUCTION SITE CONDITIONS FIELD EXPLORATION SUBSURFACE CONDITIONS DESIGN RECOMMENDATIONS FOUNDATIONS FLOOR SLABS UNDERDRAIN SYSTEM.... .. SURFACE DRAINAGE LIMITATIONS FIGURE 1 - LOCATION OF EXPLORATORY BORING FIGURE 2 - LOG OF EXPLORATORY BORING FIGURE 3 - SWELL-CONSOLIDATION TEST RESULTS TABLE 1 - SUMMARY OF LABORATORY TEST RESULTS I -1- -1- 1 -2- -2- -2- _?_ -3- -3- -4- Kumar & Associates, lnc. @ Project No. 25-7-245 PURPOSE AND SCOPE OF STUDY This report presents the results of a subsoil study for a proposed residence to be located at 19 Roan Creek Place, Lot 26, Block 2, Filing 1, Battlement Creek Village, Garfield County, Colorado. The project site is shown on Figure 1. The purpose of the study was to develop recommendations for the foundation design. The study was conducted in accordance with our agreement for geotechnical engineering services to Torrey & Sons, LLC dated April 1 ,2025. An exploratory boring was drilled to obtain information on the subsurface conditions. Samples of the subsoils obtained during the field exploration were tested in the laboratory to determine their classification, compressibility or swell and other engineering characteristics. The results of the field exploration and laboratory testing were analyzed to develop recommendations for foundation types, depths and allowable pressures for the proposed building foundation. This report summarizes the data obtained during this study and presents our conclusions, design recommendations and other geotechnical engineering considerations based on the proposed construction and the subsurface conditions encountered. PROPOSED GONSTRUCTION The proposed residence will be a one-story wood frame structure with an attached garage. Ground floor will be wood frame over a crawlspace with slab-on-grade floor in the garage. Grading for the structure is assumed to be relatively minor with cut depths between about 3 to 5 feet. We assume relatively light foundation loadings, typical of the proposed type of construction. lf building loadings, location or grading plans change significantly from those described above, we should be notified to re-evaluate the recommendations contained in this report. SITE CONDITIONS The site is currently a vacant lot vegetated with weeds and sagebrush. The lot slope is gentle to moderate down to the west between about 5o/o to 10% grade. FIELD EXPLORATION The field exploration for the project was conducted on May 16, 2025. One exploratory boring was drilled at the location shown on Figure 1 to evaluate the subsurface conditions. The boring was advanced with 4-inch diameter continuous flight augers powered by a truck-mounted CME- 45B drill rig. The boring was logged by a representative of Kumar & Associates, lnc. Samples of the subsoils were taken with a 2-inch l.D. spoon sampler. The sampler was driven into the subsoils at various depths with blows from a 140 pound hammer falling 30 inches. This test is similar to the standard penetration test described by ASTM Method D-1586. The penetration resistance values are an indication of the relative density or consistency of the subsoils. Depths at which the samples were taken and the penetration resistance values are shown on the Log of Exploratory Boring, Figure 2. The samples were returned to our laboratory for review by the project engineer and testing. Kumar & Associates, lnc, @ Project No.25-7-245 1'L- SUBSURFACE CONDITIONS A graphic log of the subsurface conditions encountered at the site is shown on Figure 2. The subsoils encountered below about Tzfoot of topsoil consist of about TTzteet of sandy silt overlying basalt gravel, cobbles and boulders in a sandy clay matrix. Drilling in the coarse granular subsoils with auger equipment was difficult due to the cobbles and boulders and drilling refusal was encountered in the deposit at 16Tzfeet. Laboratory testing performed on samples obtained from the boring included natural moisture content and density and finer than sand size gradation analyses. Results of swell-consolidation testing performed on a relatively undisturbed drive sample of the silt soil, presented on Figure 3, indicate low to moderate compressibility under conditions of loading and wetting. No free water was encountered in the boring at the time of drilling and the subsoils were slightly moist. DESIGN RECOMMENDATIONS FOUNDATIONS Considering the subsurface conditions encountered in the exploratory boring and the nature of the proposed construction, the residence can be supported with spread footings placed on the natural soils with a risk of settlement mainly if the silt soils are wetted. Extending the bearing level down to the underlying gravel and cobble soils would achieve a low foundation settlement risk. The design and construction criteria presented below should be observed for a spread footing foundation system. 1) Footings placed on the undisturbed natural soils should be designed for an allowable bearing pressure of 1900 psf.-Based on experience, we expect initial settlement of footings designed and constructed as discussed in this section will be about 1 inch or less. Additional settlement of around Tzto 1 inch could occur if the silt bearing soils are wetted. 2) The footings should have a minimum width of 18 inches for continuous walls and 2 feet for isolated pads. 3) Exterior footings and footings beneath unheated areas should be provided with adequate soil cover above their bearing elevation for frost protection. Placement of foundations at least 394SheS below exterior grade is typically used in this arca. 4 4) Continuous foundation walls should be heavily reinforced top and bottom to span local anomalies such as by assuming an unsupported length of at least '12feet. Foundation walls acting as retaining structures should also be designed to resist lateral earth pressures corresponding to an equivalent fluid unit weight of at least 50 pcf for the onsite soils as backfill. 5) The topsoil and any loose or disturbed soils should be removed and the footing bearing level extended down to the firm natural soils. The exposed soils in footing area should then be moistened and compacted. Kumar & Associates, lnc, @ Project No.25-7-245 -3- 6)A representative of the geotechnical engineer should observe all footing excavations prior to concrete placement to evaluate bearing conditions. FLOOR SLABS The natural on-site soils, exclusive of topsoil, are suitable to support lightly loaded slab-on- grade construction. To reduce the effects of some differential movement, floor slabs should be separated from all bearing walls and columns with expansion joints which allow unrestrained vertical movement. Floor slab controljoints should be used to reduce damage due to shrinkage cracking. The requirements for joint spacing and slab reinforcement should be established by the designer based on experience and the intended slab use. A minimum 4 inch layer of free- draining gravel should be placed beneath basement level slabs to facilitate drainage. This material should consist of minus 2-inch aggregate with at least 50% retained on the No. 4 sieve and less than 15% passing the No. 200 sieve. All fill materials for support of floor slabs should be compacted to at least 95o/o of maximum standard Proctor density at a moisture content near optimum. Required fill can consist of the on-site soils devoid of vegetation, topsoil and oversized rock. UNDERDRAIN SYSTEM It is our understanding that the proposed finished floor elevation at the lowest level is at or above the surrounding grade. Therefore, a foundation drain system is not required. lt has been our experience in mountainous areas that local perched groundwater can develop during times of heavy precipitation or seasonal runoff. Frozen ground during spring runoff can create a perched condition. We recommend below-grade construction, such as retaining walls and basement areas, be protected from wetting and hydrostatic pressure buildup by an underdrain and wall drain system. An underdrain is not recommended around shallow crawlspace and at-grade slabs. lf the finished floor elevation of the proposed structure is revised to have a floor level below the surrounding grade, we should be contacted to provide recommendations for an underdrain system. All earth retaining structures should be properly drained. SURFACE DRAINAGE The following drainage precautions should be observed during construction and maintained at all times after the residence has been completed: 1) lnundation of the foundation excavations and underslab areas should be avoided during construction. 2) Exterior backfill should be adjusted to near optimum moisture and compacted to at least 95% of the maxlmum standard Proctor density in pavement and slab areas and to at least 90% of the maximum standard Proctor density in landscape areas. 3) The ground surface surrounding the exterior of the building should be sloped to drain away from the foundation in all directions. We recommend a minimum slope of 12 inches in the first 10 feet in unpaved areas and a minimum slope of 3 inches in the first 10 feet in paved areas. Kumar & Associates, lnc. @ Project No.25-7-245 4) 5) Daniel E. Hardin, P.E. SLP/kac -4- Roof downspouts and drains should discharge well beyond the limits of all backfill. Landscaping which requires regular heavy irrigation should be located at least 5 feet from foundation walls. Consideration should be given to use of xeriscape to reduce the potential for wetting of soils below the building caused by irrigation. LIMITATIONS This study has been conducted in accordance with generally accepted geotechnical engineering principles and practices in this area at this time. We make no warranty either express or implied. The conclusions and recommendations submitted in this report are based upon the data obtained from the exploratory boring drilled at the location indicated on Figure 1, the proposed type of construction and our experience in the area. Our services do not include determining the presence, prevention or possibility of mold or other biological contaminants (MOBC) developing in the future. lf the client is concerned about MOBC, then a professional in this specialfield of practice should be consulted. Our findings include interpolation and extrapolation of the subsurface conditions identified at the exploratory boring and variations in the subsurface conditions may not become evident until excavation is performed. lf conditions encountered during construction appear different from those described in this report, we should be notified so that re-evaluation of the recommendations may be made. This report has been prepared for the exclusive use by our client for design purposes. We are not responsible for technical interpretations by others of our information. As the project evolves, we should provide continued consultation and field services during construction to review and monitor the implementation of our recommendations, and to verify that the recommendations have been appropriately interpreted. Significant design changes may require additional analysis or modifications to the recommendations presented herein. We recommend on-site observation of excavations and foundation bearing strata and testing of structural fill by a representative of the geotechnical engineer. Respectfully Submitted, Kumar & Associates, Steven L. Pawlak, P Reviewed by: t b a 15222 Kumar & Associates, lnc. o Project No,25-7-245 a I $ SAMPLE OF: Sondy Silt FROM:Boringl@4' WC = 3.1 %, DD = 93 pcf ADDITIONAL COMPRESSION UNDER CONSTANT PRESSURE DUE TO WETTING 0 bq JJ LJ =ta I zotr o Jotnzo(J -1 -2 -5 -4 -6 -7 1 - KSF 10 100 25-7-245 Kumar & Associates SWELL-CONSOLIDATION TEST RESULTS Fig. 5 l(+n Kumar & Associates, Inc.@ Geotechnical and Materials Engineers and Environmental Scientists TABLE 1 SUMMARY OF LABORATORY TEST RESULTS Project No,25-7-245 SOIL TYPE Sandy Silt Sandy Silt Very Clayey Sand with Gravel UNCONFINED COMPRESSIVE STRENGTH (osfl ATTERBERG LIMITS PLASTIC INDEX lo/ol LIQUID LIMTT Io/ol PERCENT PASSING NO. 200 stEVE 82 47 GRADATION SAND flt 5.2 99 GRAVEL l%') NATURAL DRY DENSTfY (pcfl 93 124 NATURAL MOISTURE CONTENT to/ol 3.1 4.2 SAI,IPLE LOCATION DEPTH (ft) 2 4 14 BORING 1 W"':i I I i i\ I R4S 8205 n?ft t tI r "!.', *.. 1 9 ROAN CRTEK PLACE 50 100 APPROXIMATE SCALE_FEET 25-7 -245 Kumar & Associates LOCATION OF EXPLORATORY BORING Fig. 1 e d R II BORING 1 LEGEND 0 N T0PSO|L; SLIGHTLY SANDY SILT WITH 0RGANICS, FIRM, SLIGHTLY MOIST, BROWN.24/12 WC=5,2 DD=99 -200=82 SILT (ML); SANDY, STIFF, SLIGHTLY M0|ST, LIGHT BRoWN, LoESS. 5 18/12 WC=5,1 DD=93 SAND, GRAVEL AND C0BBLES (SC-GC); CLAYEY, PROBABLE BOULDERS, DENSE, SLIGHTLY MOIST, MIXED BROWN. DRIVE SAMPLE, 2-INCH I.D, CALIFORNIA LINER SAMPLE. F LJ UJtL IIFo- l+lo 10 50/4 77117DR|YE SAMPLE BLOW COUNT. INDICATES THAI 24 BLOWS 0F-'' .- A 14o-POUND HAMMER FALLING 50 INCHES WERE REQUIRED TO DRIVE THE SAMPLER 12 INCHES. t PRACTICAL AUGER REFUSAL WHERE. SHOWN ABOVE BOTTOM OF BORING, INDICATES THAT MULTIPLE ATTEMPTS WHERE MADE TO ADVANCE THE HOLE. 15 37/12 Y,lC=4,2 DD=124 -200=47 NOTES THE EXPLORATORY BORING WAS DRILLED ON MAY 16, 2025 WITH A 4-INCH DIAMETER CONTINUOUS FLIGHT POWER AUGER. 20 2, THE LOCATION OF THE EXPLORATORY BORING WAS MEASURED APPROXIMATELY BY PACING FROM FEATURES SHOWN ON THE SITE PLAN PROVIDED. 3 THE ELEVATION OF THE EXPLORATORY BORING WAS NOT MEASURED AND THE LOG OF THE EXPLORATORY BORING IS PLOTTED TO DEPTH 4, THE EXPLORATORY BORING LOCATION SHOULD 8E CONSIDERED ACCURATE ONLY TO THE DEGREE IMPLIED BY THE METHOD USED 5. THE LINES BETWEEN MATERIALS SHOIryN ON THE EXPLORATORY BORING tOG REPRESENT THE APPROXIMATE BOUNDARIES BETWEEN MATERIAL TYPES AND THE TRANSITIONS MAY BE GRADUAL, 6, GROUNDWATER WAS NOT ENCOUNTERED IN THE BORING AT THE TIME OF DRILLING. 7, LABORATORY TEST RESULTS: WC = WATER 0ONTENT (%) (ASTM D 2216); DD = DRY DENSITY (PCf) (ASTM D 2216); -200 = PERCENTAGE PASSING N0. 200 SIEVE (ASTM D 1140). 25-7 -245 Kumar & Associates LOG OF EXPLORATORY BORING Fig. 2