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HomeMy WebLinkAboutSubsoils Study for Foundation Designffi GTLITHOMPSON GEOTECHNICAL ENGINEERING INVESTIGATION SWEETWATER RANCH MAIN RESIDENCE 4894 SWEETWATER ROAD GARFIELD COUNTY, COLORADO Prepared for: Beck Building Company P.O. Box 4030 Vail, CO 81658 CTLIT Project No. GS06935.000-1 25-R1 January 20,2025 CTllThompson, lnc. Denver, Fort Collins, @!orag!q;$Bd!lgs, Glenwood Sprinqs,.Pueblg,, Summit Countv - Colorado Chevenne, Wyoming and Bozeman, Montana ffi Table of Contents SCOPE. PROPERTY DESCRIPTION UPPER BUILDINGS SITE................. PROPOSED CONSTRUCTION .,...... stTE GEOLOGY...,.......... SUBSURFACE CONDtTtONS........... SITE EARTHWORK......,.. Excavations Subexcavation and Structural Fi|1....,...... Foundation Wall Backfi llUtilities........ ....................:... BU I LDTNG FOU NDATTON ......,.............,.... Footings...... SLAB-ON.GRADE CONSTRUCTION ....... CRAWL SPACE CONSTRUCTION......,.... FOUNDATION WALLS su BsuRFAc E DRA| NAGE....................... SURFACE DRAINAGE CONCRETE CONSTRUCTION OBSERVATIONS GEOTECHNICAL RISK ....... LtMtTATtONS ............. FIGURE 1 - PROPERTY BOUNDARY FIGURE 2 - DEVELOPMENT PLAN FIGURE 3 - PROPOSED UPPER BUILDINGS FIGURE 4 - PROPOSED MAIN RESIDENCE FIGURE 5 _ SUMMARY LOGS OF EXPLORATORY PITS FIGURE 6 _ GMDATION TEST RESULTS FIGIJRES 7 AND B - FOUNDATION WALL DRAIN CONCEPTS TABLE I- SUMMARY OF LABORATORY TESTING APPENDIX A - EXPLORATORY PIT PHOTOGRAPHS BECK BUILDING COMPANY SWEETWATER RANCH. MAIN RESIDENCE CTLIT PROJECT NO. GS06935.000-12s-R1 I 1 2 3 3 4 5 5 5 b 7 7 8 o 0 0 1 1 1 1 ...........12 ...........12 1 I 1 4 4 4 ffi SCOPE CTLIThompson, lnc. (CTLIT) has completed a geotechnicalengineering investigation regarding the main residence proposed at Sweetwater Ranch in Garfield County, Colorado. We conducted this investigation to evaluate subsurface conditions at the site and provide geotech- nical engineering recommendations for the planned construction. The scope of our investigation was set forth in our Proposal No. GS 24-0170-CM1 Our report was prepared from data developed from our field exploration, laboratory test- ing, engineering analysis, and our experience with similar conditions. This report includes a de- scription of the subsurface conditions found in our exploratory pits and provides geotechnical engineering recommendations for design and construction of the foundation, floor systems, be- low-grade walls, subsudace drainage, and details influenced by the subsoils. Recommendations in this report were developed based on our understanding of the currently planned construction. We should be provided with architectural plans, as they are further developed, so that we can provide geotechnical/geo-structural engineering input. PROPERTY DESCRIPTION The Sweetwater Ranch property is located west of the intersection of Sweetwater Road (County Road 40) and Sheep Greek Road (Forest Road 8450) in Eagle County, Colorado. The road intersection is about 1,000 feet northeast of the confluence of Sweetwater Creek and the East Fork of Sheep Creek. A property boundary map is included as Figure 1. The property is comprised of an east parcel of approximately 732 acres in Eagle County and a west parcel of about 1,953 acres in Garfield County. Sweetwater Creek flows to the south along the east property boundary. Mason Creek and Morris Creek, which are tributaries to Sweetwater Creek, flow down to the east in the north and south parts of the property, respec- tively. The HMS Relocated Ditch trends south across the property on the west side of the county line. The property is generally comprised of a hummocky terrace that slopes down to the southeast. Steep slopes drop down from higher elevations adjacent to the property boundary at the west and south. The creek channels are incised in the terrace terrain. The east edge of the property is on the valley floor of the Sweetwater Creek drainage. Several reservoirs and ponds BECK BUILDING COMPANY SWEETWATER RANCH. MAIN RESIDENCE GTLIT PROJECT NO. GSo6935.000-125-R1 Page 1 of 15 ffi are present on the upper pafts property. Ranch roads provide access to various parts of the property and facilities, including residences and agricultural buildings. Numerous irrigated hay- fields and pastures are on the property. Natural vegetation adjacent to the irrigated areas con- sists of oak brush, pinion and juniper trees, aspen trees, and sage brush. UPPER BUILDINGS SITE The upper buildings are proposed within, and adjacent to, an irrigated hayfield that is about 1,200 feet west of the county line. The center of the development areas is about 700 feet from the crest of the steep slope that drops down to the Morris Creek drainage. The alignment of the HMS Relocated Ditch is downhill of the general location, about 800 feet to the northeast. At this writing, the proposed buildings include a main residence, community barn, and three guest cabins. The development plan is shown on Figure 2. The main residence is planned on a topographic knob that is east of the hayfield. Ground surface at the location slopes down to the north, east, and south at grades of about 5 to 20 percent. Vegetation at the main residence consists of sage brush and grass with scattered pinion and juniper trees. We observed numerous sandstone cobbles and boulders at the ground surface. A photograph of the main residence site is below. The upper buildings site is shown on Figure 3. Looking east across main residence site BECK BUILDING COMPANY SWEETWATER RANCH. MAIN RESIDENCE cTLIT PROJECT NO. GS06935.000-125-R1 Page 2 of 15 ffi PROPOSED CONSTRUCTION CTLIT was provided with schematic design drawings for the main residence by Centre Sky Architecture, LTD (dated December 13,2024). The residence is planned with a twoJevel core living area. Three, one-level building wings will extend from the upper level of the core liv- ing area. The north wing will be the master suite, the south wing will.be the guest wing, and the west wing will be the garage. Floor elevations in the wings will be at or near the main floor ele- vation in the core living area. The proposed main residence footprint is shown on Figure 4. It appears the lower-levelfloors in the core living area will be slabs-on-grade near eleva- tion7682 feet. A slab-on-grade floor is planned in the garage near elevation 7694 feel The schematic design drawings indicate the floors in the master suite and guest wing will be at ele- vation 7694 feet and may be structurally supported with crawlspace areas below. Patios, walk- ways, and an auto court will be adjacent to the building exterior. The building will likely be steel-framing with cast-in-place foundation walls. Maximum foundation excavation depths of about 10 to 15 feet are anticipated at the uphill side of the lower level. We expect foundation loads between 3,000 and 4,000 pounds per linear foot of foundation wall and column loads of less than 75 kips. SITE GEOLOGY As pafi of our geotechnical engineering investigation, we reviewed geologic mapping by the U.S. Geological Survey (USGS) titled, "Geologic Map of the Leadville 1 Degree x 2 Degree Quadrangle, Northwestern Colorado", by Tweto, Moench, and Reed (dated 1978). We also re- viewed mapping by the Colorado geological survey titled, "Geologic Map of the Dotsero Quad- rangle, Eagle and Garfield Counties. The maps indicate the soils at the planned site of the up- per buildings consist of landslide deposits of the Holocene and Pleistocene Epochs. These ma- terials are unconsolidated, unsorted, and unstratified. The materials are homogeneous and range in size from cobbles and boulders to silt and clay. We judge the soils found in our explora- tory pits for the main residence are consistent with landslide deposits. Based on geologic mapping and our site observations, it appears the overburden soils are underlain at depth by bedrock of the Minturn Formation (Middle Pennsylvanian Period) and BECK BUILDING COMPANY SWEETWATER RANCH - MAIN RESIDENCE crllr PRoJEcT NO. GS06935.000-1 25-R1 Page 3 of 15 ffi Belden Formation (Lower Pennsylvanian Period). The Minturn Formation is generally gray, tan, and red sandstone, conglomerate, and shale. The Belden Formation is dark gray to black shale and carbonate rocks and sandstone. The mapping indicates the bedrock formations are undi- vided in the vicinity of Sweetwater Creek. The weathered sandstone and sandstone bedrock encountered in our MR-C pit appeared consistent with The Minturn Formation. SUBSURFACE CONDITIONS Subsurface conditions at the main residence site were investigated by directing excava- tion of three exploratory pits (MR-A through MR-C) at the approximate locations shown on Fig- ures 3 and 4. The pits were excavated with a trackhoe on November 18, 2025. Exploratory ex- cavation operations were directed by our engineer, who logged subsurface conditions encoun- tered and obtained samples of the subsoils. Graphic logs of subsurface conditions found in our exploratory pits are shown on Figure 5. Subsurface conditions encountered in our exploratory pits, MR-A and MR-8, consisted of about 6 to 12 inches of topsoil, underlain by clayey gravel and sandy clay to the total exca- vated depths of 14 and 1 1.5 feet, respectively. Exploratory pit, MR-C, exposed 1 foot of topsoil, 5 feet of clayey gravel and sandy clay, and 3.5 feet of weathered sandstone, underlain by com- petent sandstone. The hardness of the sandstone made exploratory excavation deeper than 10 feet not practical. Photographs of the exploratory pits and excavated materials are attached as Appendix A. Groundwater was not encountered in our exploratory pits at the time of our subsurface investigation. The pits were backfilled immediately after exploratory excavation operations were completed. Samples of the subsoils obtained from our exploratory pits were returned to our laborato- ry for pertinent testing. Laboratory testing included Atterberg limits and gradation analyses. Gradation analysis results are shown on Figure 6. Laboratory testing is summarized on Table l. BECK BUILDING COMPANY SWEETWATER RANCH. MAIN RESIDENCE cTLIT PROJECT NO. GS06935.000-125-Rl Page 4 of '15 ffi SITE EARTHWORK Excavations Based on our subsurface investigation, we expect excavations for construction of the main residence can be accomplished using conventional, heavy-duty excavating equipment, such as a medium-sized trackhoe. Excavations more than a few feet into the bedrock may re- quire a hydraulic hammer attachment on a trackhoe. From a "trench safety" standpoint, sides of excavations must be sloped or retained to meet local, state, and federal safety regulations. The soils in excavations at this site will likely classify as Type B and Type C soils, based on OSHA criteria. Excavations deeper than 5 feet and above groundwater should be sloped no steeper than 1 to 1 (horizontal to vertical) in Type B soils and 1.5 to 1 in Type C soils. Groundwater seepage into excavations can cause slumps and sloughing and the need for flatter slopes. Contractors are responsible for site safety and providing and maintaining safe and stable excavations. Contractors should identify the soils en- countered in excavations and ensure that OSHA standards are met. CTLIT did not encounter a groundwater table in our exploratory pits. Our experience in similar geologic conditions in the region indicates that the upper soils can become saturated during snowmelt in spring and early summer. Zones of groundwater seepage could occur in ex- cavations at the site. lt appears feasible that construction dewatering can be accomplished by sloping excavations to gravity outlets or to sump pits where water can be removed by pumping. Trenches along the perimeter of the excavation, outside the structure footprint, can help convey water to outlets or sumps. We recommend that excavation and earthwork operations commence after peak snowmelt has occurred. Subexcavation and Structural Fill The overburden soils at this site are relatively heterogeneous. Furthermore, the soils have not been subject to geologic loads and have potentialfor consolidation when wetted under building loads. We judge the use of footings and slabs-on-grade is reasonable, provided poten- tialfor differential building movement is mitigated. BECK BUILDING COMPANY SWEETWATER RANCH - MAIN RESIDENCE cTLlr PROJECT NO. GS06935.000-125-R1 Page 5 of 15 ffi To create more uniform support conditions and reduce the potential for differential movement of foundations for the building, we recommend subexcavation of the soils below the bottoms of footings and floor slabs to a depth at least 3 feet. The sub-excavated areas should extend laterally at least 1 foot beyond the edges of footings and slabs. The excavated soils should be replaced with densely-compacted, structural fill. The excavated soils can be reused as structuralfill, provided they are screened to re- move rocks larger than 4 inches in diameter, organics, and debris. lmport soil needed for struc- tural fill should consist of a clayey sand or gravel with a maximum rock size of 4 inches and 20 to 40 percent sit and clay material. A sample of potential import soil for structural fill should be subntitted to CTLIT for approval prior to the hauling to the site. Structural fill should be placed in loose lifts of I inches thick or less, moisture- conditioned to within 2 percent of optimum moisture content and compacted to at least g8 per- cent of standard Proctor (ASTM D 698) maximum dry density. Moisture content and density of structuralfill should be checked by a representative of CTLIT during placement. Observation of the compaction procedure is necessary. Foundation Wall Backfill Proper placement and compaction of foundation backfill is important to reduce infiltration of surface water and settlement from consolidation of backfill soils. This is especially important for backfill areas that will support exterior concrete flatwork, such as patios, walkways, and driveways. The excavated soils can be reused as backfill, provided they are screened to remove or- ganics, debris, and rocks larger than 6 inches in diameter. Backfill should be placed in loose lifts of approximately 10 inches thick or less and moisture-conditioned to within 2 percent of opti- mum moisture content. Backfill soils that will not support exterior concrete slabs should be compacted to at least 95 percent of standard Proctor (ASTM D 698) maximum dry density. Backfill soils that will sup- port exterior concrete slabs should be compacted to at least 98 percent of ASTM D 698 maxi- BFCK BIIII NING COMPANY SWEETWATER RANCH. MAIN RESIDENCE CTLIT PROJECT NO. cs06935.000-12s-R,l Page 6 of 15 ffi mum dry density. Moisture content and density of the backfill should be checked during place- ment by CTLIT. Observation of the compaction procedure is necessary Foundation backfill that will support exterior slabs requires strict adherence to specifica- tions. Even well-placed backfill will settle 0.5 to 1 percent of total backfill thickness. Structures placed over backfill zones will need to be designed to accommodate differential movement with respect to the building. lf slabs and structures that are sensitive to settlement will be located above deeper zones of backfill, consideration should be given to designing these elements as structurally supported. Utilities Sides of utility trenches should be sloped or braced to meet local, state and federal safe- ty requirements. Anticipated OSHA soiltype classifications were provided in the Excavations section. We believe the natural soils at this site have low corrosion potential. We can perform re- sistivity testing to assist in judging corrosivity of the native soils, if desired. Water mains and other utilities may be constructed of common ductile iron pipe. Some municipalities recommend iron fittings, joints, couplings and appurtenances be wrapped with polyethylene for corrosion protection regardless of soil resistivity. Properly compacted backfill in utility trenohes is important to reduce subsequent oonsoli- dation of backfill soils and infiltration of sudace water. Backfill soils should consist of the on-site soils, free of rocks larger than 4 inches in diameter, organic matter and debris. Backfill should be placed in thin lifts, moisture conditioned to within 2 percent of optimum moisture content and compacted to at least 95 percent of standard Proctor (ASTM D 698) maximum dry density. Density and moisture content of backfill should be checked by CTLIT during placement. BUILDING FOUNDATION The overburden soils at this site are relatively heterogeneous. Furthermore, the soils have not been subject to geologic loads and have potentialfor consolidation when wetted under BECK BUILDING COMPANY SWEETWATER RANCH - MAIN RESIDENCE cTLIT PROJECT NO. GS06935.000-125-Rl Page 7 of 15 building loads. We judge the use of a footing foundation is reasonable for the main residence, provided potentialfor differential building movement is mitigated. To create more uniform support conditions and reduce the potential for differential movement of foundations for the building, we recommend subexcavation of the soils below the bottoms of footings to a depth at least 3 feet. The sub-excavated areas should extend laterally at least 1 foot beyond the edges of the building footprint. The excavated soils should be re- placed with densely-compacted, structural fill in accordance with recommendations in the Subexcavation and Structural Fill section. Recommended design and construction criteria for footings are below. These criteria were developed based on our analysis of field and laboratory data, as well as our engineering experience. Footinqs Footings should be supported by densely-compacted, structuralfill that is at least 3 feet thick. The structuralfill should be in accordance with recommendations in the Subexcavation and Structural Fill section. Footings on densely-compacted, structuralfill can be designed for a maximum net allowable soil bearing pressure of 3,000 psf. The weight of backfill soils above the footings can be neglected for bearing pressure calculation. A 1,000 psf increase in this bearing pressure is acceptable when using the alternative load combination of IBC 2015, Section 1605.3.2 that include wind and earthquake load. A friction factor of 0.35 can be used to calculate resistance to sliding between concrete footings and the structural fill. Continuous wall footings should have a minimum width of at least 18 inches. Foundations for isolated columns should have minimum dimensions of 30 inches by 30 inches. Larger sizes may be required, depending upon foundation loads. Grade beams and foundation walls should be well-reinforced. We recommend re- inforcement sufficient to span an unsupported distance of at least 12 feet. The soils under exterior footings should be protected from freezing. We recom- mend the bottom of footings be constructed at least 42 inches below finished ex- terior grades for frost protection. The Garfield County building department should be consulted regarding frost protection requirements. BECK BUILDING COMPANY SWEETWATER RANCH. MAIN RESIDENCE CTLIT PROJECT NO. GS06935.000-1 25-R1 1 2. 3. 4. 5 6 Page 8 of 15 ffi SLAB-ON.GRADE CONSTRUCTION The overburden soils at this site are relatively heterogeneous. Furthermore, the soils have potential for consolidation when wetted under building loads. We judge the use of slab-on- grade floors and exterior flatwork is reasonable, provided potential for differential movement is mitigated. To create more uniform support conditions and reduce the potentialfor differential movement of foundations for the building, we recommend subexcavation of the soils below the bottoms of interior slabs to a depth at least 3 feet. The sub-excavated areas should extend lat- erally at least 1 foot beyond the edges of the slabs. A minimum structuralfillthickness of 12 inches is recommended below exterior flatwork. The excavated soils should be replaced with densely-compacted, structural fill in accordance with recommendations in the Subexcavation --and Structural Fill section Based on our analysis of field and laboratory data, as well as our engineering experi- ence, we recommend the following precautions for slab-on-grade construction at this site. Slabs should be separated from footings and columns pads with slip joints which allow free vertical movement of the slabs. The use of underslab plumbing should be minimized. Underslab plumbing should be pressure tested for leaks before the slabs are constructed. Plumbing and utili- ties which pass through slabs should be isolated from the slabs with sleeves and provided with flexible couplings to slab supported appliances. Exterior patio slabs and concrete flatwork should be isolated from the building These slabs should be well-reinforced to function as independent units. Frequent controljoints should be provided, in accordance with American Con- crete lnstitute (ACl) recommendations, to reduce problems associated with shrinkage and curling. The lnternational Building Code (lBC) may require a vapor retarder be placed be- tween the base course or subgrade soils and concrete slab-on-grade floors. The merits of installation of a vapor retarder below floor slab depend on the sensitivity of floor coverings and building to moisture. A properly installed vaper retarder (10 mil minimum) is more beneficial below concrete slab-on-grade floors where floor coverings will be sensitive to moisture. The vapor barrier/retarder is most effec- tive when concrete is placed directly on top of it. A sand or gravel leveling course should not be placed between the vapor barrier/retarder and the floor slab. BECK BUILDING COMPANY SWEETWATER RANCH - MAIN RESIDENCE CTLIT PROJECT NO- GS06935.000-1 25-R1 1 2 3. 4. 5. Page 9 of 15 ffi CRAWL SPACE CONSTRUCTION The schematic design drawings indicate that crawl space areas may be constructed be- low parts of the main-level floors in the master suite and guest wing. The required crawl space height depends on the materials used to construct the floor system above the crawl space. Building codes normally require a clear space of at least 18 inches between exposed earth and untreated wood components of the structural floor. Utility connections, including water, gas, air duct, and exhaust stack connections to ap- pliances on structural floors should be capable of absorbing some deflection of the floor. Plumb- ing that passes through the floor should ideally be hung from the underside of the structural floor and not laid on the bottom of the excavation. Control of humidity in crawl spaces is important for indoor air quality and performance of wood floor systems. We believe the best current practice to control humidity involve the use of a vapor retarder or vapor barrier (10 mil minimum) placed on the soils below accessible subfloor areas. The vapor retarder/barrier should be sealed at joints and attached to concrete foundation elements. lt may be appropriate to install a ventilation system that is controlled by a humidistat. FOUNDATION WALLS Foundation walls that extend below-grade should be designed for lateral earth pressures where backfill is not present to about the same extent on both sides of the wall, such as in basements and crawl spaces. Many factors affect the values of the design lateral earth pres- sure. These factors include, but are not limited to, the type, compaction, slope, and drainage of the backfill, and the rigidity of the wall against rotation and deflection. For a very rigid wallwhere negligible or very littte deflection will occur, an "at-rest" lateral earth pressure should be used in design. For walls that can deflect or rotate 0.5 to 1 percent of wall height (depending upon the backfill types), design for a lower "active" lateral earth pressure may be appropriate. Our experience indicates typical below-grade walls in residences deflect or rotate slightly under normal design loads, and that this deflection results in satisfactory wall per- formance. Thus, the earth pressures on the walls will likely be between the "active" and "at-rest" conditions. BECK BUILDING COMPANY SWEETWATER RANCH - MAIN RESIDENCE cTLIT PROJECT NO. cS0693s.000-1 zs-Rl Page 10 of 15 ffi For backfillsoils conforming with recommendations in the Foundation Wall Backfillsec- tion that are not saturated, we recommend design of below-grade walls at this site using an equivalent fluid density of at least 45 pcf. This value assumes deflection; some minor cracking of walls may occur. lf very liftle wall deflection is desired, a higher design value for the "at-rest" condition is appropriate using an equivalent fluid pressure of 60 pcf,. SUBSURFACE DRAINAGE Our experience in similar geology and topography in the region indicates the upper soils can become saturated during snowmelt in spring and early summer months. Frozenground dur- ing spring runoff can also create a perched condition. Additionally, water from precipitation, snowmelt, and irrigation frequently flows through relatively permeable backfill placed adjacent to a residence and collects on the surface of less permeable soils at the bottom of foundation ex- cavatiohs. These sources of water can cause wet or moist conditions in below-grade areas after construction. To reduce the likelihood water pressure will develop outside foundation walls, we recommend provision of a foundation wall drain around the perimeter of the main residence foundation. The foundation wall drain should consist of 4-inch diameter, slotted PVC pipe encased in free-draining gravel. A prefabricated drainage composite should be placed adjacent to founda- tion wall exteriors. Care should be taken during backfill operations to prevent damage to drain- age composites. The drain should discharge via positive gravity outlets. The gravity outlets shoukl not be susceptible to cloggirrg or freezing. We recommend installation of a clean-outs along the drainpipes. A representative of our firm should be called to observe the drain con- struction, prior to backfilling. To further mitigate subsurface water, we recommend a drainage layer (below slabs and on crawl space floors) consisting of 4-inch diameter, slotted PVC pipe installed on 8 to 10-foot centers and embedded in at least 6 inches of screened rock. lf a vapor barrierlretarder is placed below the slabs, the gravel layer should be below the barrier. The pipes should convey water to perimeter drain collector pipes. Water collected should be discharged via positive gravity out- lets. The foundation walldrain concepts are shown on Figures 7 and 8. BECK BUILDING COMPANY SWEETWATER RANCH. MAIN RESIDENCE cTLIT PROJECT NO. GS06935.000-125-Rl Page 11 of 15 ffi SURFACE DRAINAGE Surface drainage is critical to the performance of foundations, floor slabs, and concrete flatwork. Surface drainage should be designed to provide rapid runoff of surface water away from the residence. Proper surface drainage and irrigation practices can help controlthe amount of surface water that penetrates to foundation levels and contributes to settlement of soils that support the building foundation and slabs-on-grade. Positive drainage away from the building fuurrdation and avoidance of lrrlgatlon near the foundation also help to avoid excessive wetting of backfill soils, which can lead to increased backfill settlement and possibly to higher lateral earth pressures, due to increased weight and reduced strength of the backfill. We recommend the following precautions. The ground surface surrounding the exterior of the residence should be sloped to rapidly convey surface water away from the building in all directions. We recom- mend a constructed slope of at least 12 inches in the first 10 feet (10 percent) in landscaped areas around the residence, where practical. Backfill around the foundation walls should be moisture-treated and compacted pursuant to recommendations in the Foundation Wall8ackfill section. We recommend that the residence be provided with roof drains or gutters and downspouts. The drains or downspouts should discharge well beyond the limits of all backfill. Splash blocks and/or extensions should be provided so water dis- charges onto the ground beyond the backfill. We generaliy recommend against burial of downspout discharge pipes. 4.Landscaping should be designed and maintained to minimize irrigation. Plants placed close to foundation walls should be limited to those with low moisture re- quirements. lrrigated grass should not be located within 5 feet of the foundations. Sprinklers should not discharge within 5 feet of foundations. Plastic sheeting should not be placed beneath landscaped areas adjacent to foundation walls. Geotextile fabric will inhibit weed growth and allow some evaporation to occur. CONCRETE Concrete in contact with soil can be subject to sulfate attack. Our experience with pro- jects in similar geology indicates the soils have water soluble sulfaie concentrations of less than 0.10 percent. Pursuant to our test and ACI 332-20, this concentration corresponds to a sulfate exposure class of "Not Appticable" or RSO as indicated on the table below. BECK BIJII-NING CNMPANY SWEETWATER RANCH - MAIN RESIDENCE CTLIT PROJECT NO. cS06935.000-125-R1 1 2. 3. Page 12 of 15 SULFATE EXPOSURE CLASSES PER ACI 332-20 A) Percent sulfate by mass by ASTM C1580 For this level of sulfate concentration, ACI 332-20,"Code Requirements for Residential Concrete", indicates no special cement type requirements for sulfate resistance as indicated on the table below. CONCRETE DESIGN REQUIREMENTS FOR SULFATE EXPOSURE PER ACI 332-20 A) Concretecompressive B) Alternatecombinations strength be based on 28-day tests per ASTM C39/C39M of cementitious materials of ihose listed in ACI 332-20 Table 5.4.2 shall be permitted when tested for sulfate resistance meeting the criteria in section 5.5. C) Other available types of cement such as Type lll or Type I are permitted in Exposure Classes RSI or RS2 if the C3A contents are less than 8 or 5 percent, respectively. D) The amount of the specific source of pozzolan or slag to be used shall not be less than the amount that has been determined by service record to improve sulfate resistance when used in concrete containing Type V cement. Alternatively, the amount of the specific source of the pozzolan or slab to be used shall not be less than the amount tested in accordance wiih ASTM C10121C1012M and meeting the criteria in section 5.5.1 of ACt332-20. E) Water-soluble chloride ion content that is contributed from the ingredients including water aggregates, ce- mentitious materials, and admixtures shall be determined on the concrete mixture ASTM C12181C1218M between 29 and 42 days. Superficial damage may occur to the exposed surfaces of highly permeable concrete. To control this risk and to resist freeze thaw deterioration, the water-to-cementitious materials ratio should not exceed 0.50 for concrete in contact with soils that are likely to stay moist due to sur- BECK BUILDING COMPANY SWEETWATER RANCH. MAIN RESIDENCE cTLlr pRoJEcT NO. GS06935.000-125-Rl . Water-Solu ble Sulfate (SOr) in SoilA (o/o\ Exposure Classes < 0.10Not Apolicable RSO RS1 O-10 to 0.20Moderale 0.20 to 2.00SevereRS2 RS3 > 2.OOVery Severe Exposure Class Maximum Water/ Cement Ratio Minimum Compressive Strength A (psi) I B Calcium Chlo- ride Admix- ' tures ASTM c150/ c150M ASTM c595/ c595M ASTM c1157t c1157M RSO N/A 2500 No Type Restrictions No Type Restrictions No Type Restrictions No Restrictions RS1 0.50 2500 Type with (MS) Designation MS No Restrictions RS2 0.45 3000 Vc Type with (HS) Designation HS Not Permitted RS3 0.45 3000 V + Pozzolan or Slag Cement D Type with (HS) Designation plus Pozzolan or Slag Cement E HS + Pozzolan or Slag Cement E Not Permitted Page 13 of 15 ffi face drainage or high-water tables. Concrete should have a total air content of 60/o +/-1.5%. We recommend foundation walls and grade beams in contact with the subsoils be damp-proofed. CONSTRUCTION OBSERVATIONS We recommend that CTLIT be retained to provide construction observation and materi- als testing seryices for the project. This would allow r-rs the opportunity to verify whether goil conditions are consistent with those found during this investigation. lf others perform these ob- servations, they must accept responsibility to judge whether the recommendations in this report remain appropriate. lt is also beneficialto projects, from economic and practicalstandpoints, when there is continuity betwccn angineering consultation and the construction observation ancl materials testing phases. GEOTECHNICAL RISK The concept of risk is an important aspect of any geotechnical evaluation. The primary reason for this is that the analytical methods used to develop geotechnical recommendations do not comprise an exact science. We never have complete knowledge of subsurface conditions. Our analysis must be tempered with engineering judgment and experience. Therefore, the rec- ommendations presented in any geotechnical evaluation should not be considered risk-free. We cannot provide a guarantee that the interaction between the soils and the proposed residence will lead to performance as desired or intended. Our recommendations represent our judgment of those measures that are necessary to increase the chances that the building will perform sat- isfactorily. lt is criticalthat all recommendations in this report are followed. LIMITATIONS This report was prepared for the exclusive use of Beck Building Company with respect to the main residence proposed at Sweetwater Ranch. The information, conclusions, and recom- mendations provided herein are based upon consideration of many factors including, but not limited to, the type of structure proposed, the geologic setting, and the subsurface conditions encountered. fhe conclusions and recommendations contained in the report are not valid for use by others. Standards of practice continuously change in geotechnical engineering. The rec- ommendations provided in this report are appropriate for about three years. lf the proposed BEGK BUILDING COMFANY SWEETWATER RANCH - MAIN RESIDENCE CTLIT PROJECT NO. cS0693s.000-125-R1 Page 14 of 15 ffi building is not constructed within three years, we should be contacted to determine if we should update this report. Our exploratory pits provide a reasonable characterization of subsurface conditions at the site. Variations in subsurface conditions not indicated by the pits will occur. We should be provided with architectural plans, as they are further developed, so we can provide geotech- nical/geo-structural engineering input. This investigation was conducted in a manner consistent with that level of care and skill ordinarily exercised by geotechnical engineers currently practicing under similar conditions in the locaiity of this project. No warranty, express or implied, is made. Please contact us if we can be of further service in discussing the contents of this report. OMPSON, IN Reviewed by: lh l?- D or Principal Engin BECK BUILDING COMPANY SWEETWATER RANCH - MAIN RESIDENCE CTLIT PROJECT NO. GS06935.000-125-Rl Barbone, Division Manager Page 15 of 15 + LEGEND:tr APPROXIMAIE LOCITION OT PROPERW BOUNDARY APPROXIMATE LOCATION OF COUNTY UNE 0tm&Erl NOIE S{'IEIIJIE III^OE FROM MAOR (coPYRrcHr 2022) aggU[l,,E(rcarPNim|MGtAEl.urffi Prq@t ilo. OAO@36.(n-125 Proper$ Boundary Eg. 1 { 0&t@r 3EA( BUllOSp @MpA$t.EMmN|.Hw Frqsot r\b. CAO6O35.0OO-r 26 ffi :_ APPROXTMATE LOCAIION OF PROPERTY BOUNDARIES NolE: SATEILfE UAOE FROM GoOotE EAR]}I (0AIED AUGUivt 3, 2025) Fg. 2 Development Plan s .ag eEuFntlg reddn nerodo6 & t€dgv tEEUoEfflE lg U.l!l|Wd l$rrE :gION ud llo,aaoldxr Jo ltollllfi ilwfioudd,I v1&t. :0tEtroyl 9Z!'00O'I@O'91.1 lidoFrd'ffiM-ffi5Wtf{v4!66 5ptrllrl !5Ed {C.J Cilr.ffi J I ffi LEGEND: o SCALE: 1'* '100' MR_AI NOTE: 100 APPROXIMATE LOCATION OF EXPLORATORY PIT BASE DRAWING BY BLUEGREEN ASPEN (DATED DECEMBER 3, 2024) \ --* \ ( \ BECKBUILDING COMPANY SWEETWATER RANCH - MAIN BESIDENOE cTUr PROJECT NO. GSO6935.O0O-125 Proposed Main Residence Flg. 4 trMR.A EL, 7€92 MR.B E1,7684 MR.C EL.7IM 7706 7700 7095 7690 tGOEilO: MAIN LEVEL FLOOR EL 7694 W ,n_ ffi rocsou cuv. snov, Mors, DARK BRM.u cuEvomwLNsoYuy,asnErooNouwsmNEcoBEE. muM ElsE oR flF, MO|ST, EROVIN, TN. (GC, Sq CU ' I cuv, wov, uaouu $rrF ro sF, Morsr. sRM. (c0 Qwnzaeo lunmrone WDsuE, FMCruruO, MEDIUM HARO, SUGMY rcFT, IN. INDISftS AUK SUPLE ONANEO MOM AqVATED S16. F CRAW- SFACE FLOOR EL. 7682 NOIES: 7685 7680 7875 sUIII|MARY LOOE OF EXFLORATORY FITTI 1. gPtoMTRYPtrSWRE AUVATEDWTHARCffiOEOd NOWMEERT6, 20A. 2. *oUNDWATER wr€ Nfr FouE tN M wlomToRy ptrgAT fr E nffi 6F SCAVATON. fiE PIre WSRE $CTIUb IWEDNTTY AMR gPLOSTfiY gavaroN @EMlotra m* ffrEo. LOWER LEVEL FLOOR EL. 7682 3. qPrcMTffY PT EWATIONS WERE ESUEO Mil GROUNO SUtrrcE EilANON 4. THEAEI$&ESUilECTTnE qPlsTtds. IMtrAtrONSNOCOTLUSIdS|Rills sPoF. BECK SUILOINO @PANYSWEilAER MNCH. HN EEErcEcnII PROJffi NO ffiS6.mtH!FIG. 5 B a E ffi SANDS GRAVEL MEDIUM COARS FINE COARSE COBBLEScLAY (PLASTTC) TO SILT (NON.PLASTIC) FINE SIEVEHYOROMETER ANALYSIS 2roa,6 s60 Fz H50Et!d40 30 20 10 0 0 10 20 30 40 50 60 70 80 90 100 F2trl(,tU 100 .00r 0.002 .005 .009 ,019 .037 .o74 .149 DIAMETER OF PARTICLE IN MILLIMETERS CLEAR SOUARETIME REAOINGS 60 MtN. 19 MtN. 4 MtN. 1 MtN. '200 U,S. STANDARO SERIES .100 .50 '40'30 .297 .590 0.42 't.19 2.O 2.38 4.76 9.52 19.1 36.1 76.2 12\s22OO .4 3/8" 3t4', 'lli', 3' 5"6' 8" 25 HR. 7 HR. 45MtN. lsMtN. Somple of cLAy, sANDy (cL)From Mn-e Af s-sFEEi Somple of GRAVEL, cLAyEy (cc)From un:.c Ai z-J FEEf BECK BUILDING COMPANY SWEETWATER RANCH - MAIN RESIDENCE PROJECT NO. GS06935.000-125-R1 GRAVEL 16% srlr a cuv of % PLASTICITY INDEX GRAVEL 37 o/o srLT & oLAY i7 ,t" pusrtctrv tnoef SAND LIAUID LIMIT SAND 26 t-tOUtO t-ttritlt 23% Vo o/o To o/o o/o Gradation Test Results GRAVELSANDS FINE MEDIUM COARS FINE COARSE COBBLEScLAY (PLASTTC) TO SILT (NON-PIASTTC) ANALYSIS 100 90 80 (no zo @ fl60 Fz 350EUoro 30 20 t0 0 l0 20 30 40 50 60 70 80 90 100 - = - 127 200 152 s.52 1S.l 36.1 76.2.001 0.002 .005 .009 .019 .037 U.S. STANDARD SERIES.100 '50 '40'30 ''16 '10 '8 CLEAR SOUARE OPENINGS 3/8" 3t4' 1vl', 3" 5"6" TIME READINGS 50 MtN. t9 MtN. 4 MtN. I MlN. ',200 .o74 .149 .2970.42.590 1.'19 2.O 23A 4.76 DIAMETER OF PARTICLE IN MILLIMETERS 25 HR. 7 HR. 45 MtN. 15 MtN. FIG.6 tr SLOPE 2-5' BACKN\ PREFABRICATED DRNMGE coMPosm (MTMDMTN So0O oR EOUTVAENT) SLOPE ATTACH PLASTE SHEENNG OSHA TO FOUNDATIONPER S]JP JOINT COVER ENNRE WDTH OF GRA!'EL |TTH NON-WOVEN CEOTEfiI.E FABRIC (MIRAFI 14ON OR EAUVATENi)..r aaa:].a ENCASE PIPE IN GRAVEL DfiEND AtlD AT LEASf ENNRE TRE}.ICH BECKBUILDING COMPAI{Y AWEETWATEfi nANcFl - lvlAlN 8E9IDENCE ProJect No. GS06935.OOO-1 25 1/2'TO 1-1/2'SCREENED GMVEL IATERAI.I-Y TO FOOTINGl/2 HACW OF FOOING. Rrr- WTH GRAI/EL t+.r I ruC DRNN NETIYORK EMBEDDED IN WASHED CONCRETE AGGREGAIE J a a : :2.;:;i MINIMUM 6, MINIMUM OR BETONDI:1 SLOPE FROM BOTTOM OF FOOTING (wHrcHflER tS GREATER) 4-INCH DIA}JIEIER PERFORATED RIGID DMIN PIPE. THE PIPE SHOUII) BE PIACED IN A TRENCH WNH 4_9!OPE .ol ir lEAsr lrlE-tNcH DRop pER FOOT OF DRAIN. NOIE: THE BOTTOM OF THE DRAIN SHOUL.D BE AT IEAST 2 INCHES BETOIV BOTTOM OF FOOTING AT IHE HIGHST PONT AND SLOPE DOTVNTVARD TO A POSfiTVE GRAVTTY O.l.jTi.EI OR TO A SUMP IVHERE WATER cAI{ EE REI,o\IED Br PUMPING. Foundation Wall Drain Concept Flg.7 STRUCruRAL FLOOR SLOPE 2-3' BACKN\ PREFABRICATED DRNMGE coMPosm (MTRADRNN 6000 oR EQUTVAT.EM) GRAVET WITH NON-WOVEN GEOTEfltE FABRIC (UNATI r40N oR EauvArEl$). BECK BUILDING COMPAI{Y AiVEETWATEF RANCII' MAIN BESIDENCE ProJect No. GSO6935.O0O-1 25 ATTACH PI.ASNC SHEENNG TO FOUNDATION E, MINIMUM OR BEYOND 1:1 SLOPE FROM BOTTOM OF FOOTING (wHrcHR/ER rS GREATER) 4-INCH DIAIJ|ETER PERFT}RATED RIGID DRAN PIPE. THE PIPE SHOUTD BE PIACED IN A TRB{CH wlIH A SLOPE OF AT LEASr trlE-tNCH DROP PER FOOT OF DRAIN. SLOPE PER OSHA COVER ENNRE WIDTTI OF '-cMwL sPece -/ I t .r rrl'. .}r trl: ..r I 't2i tf,l ..i t a .MUD SLAB' oR BA,RRIER l ts' WC DRAIN NETWORK EMBEDDED lN WNHED CONCRETE AGGREGATE ENCASE ptpE tN 1/2'TO 1-l/2' SCREENED GRAVEL DfiEND GRAIGL I.ATEM,I.LY TO FOOTING AltD AT tEASr 1/2 HEtCt{l OF FOOTING. Fru- E}MRE TRENCH WITH GRAVEL NOTE TIIE BOTTOM OF TTIE DRAIN SHOUTD BE AT I.EAST 2 NCHES BELOW BOTTOM OF FOONNC AT THE HIGHEST PONT AND SLOPE DOTT}.ITTARD TO A POSIITVE GRAVTTY OI'N..ET OR TO A SUMP WHERE WATER CAI{ BE RE},IOVED Ff PUMPING. Foundation Wall Drain Concept Flg.8 TABLE I SUMMARY OF LABORATORY TESTING CTLIT PROJECT NO. GS06935.000-125-R1 ffi DESCRIPTION SANDY cc) CLAY, SANDY PASSING NO.200 SIEVE (o/o\ 62 61 37 PERCENT SAND (%\ 23 26 PERCENT GRAVEL (o/o\ 16 37 SOLUBLE SULFATES (o/o) *SWELL (%) ATTERBERG LIMITS PLASTICITY INDEX (%) 20 LIQUID LIMIT (o/o\ 40 DRY DENSITY (PCF) MOISTURE CONTENT (o/o\ 15.4 8.7 6.7 DEPTH (FEET) 4-5 8-9 2-3 EXPLOMTORY BORING MR-A MR-B MR-C *SWELL MEASURED UNDER 1,OOO PSF APPLIED PRESSURE. NEGATIVE VALUE INDICATES CONSOLIDATION.Page 1 of 1 ffi APPENDIX A EXPLORATORY PIT PHOTOGRAPHS BECK BUILDING COMPANY SWEETWATER RANCH - MAIN RESIDENCE cTLIT PROJECT NO. GS06935.000-125-R1 ffi ,,i++ Mr+Y{trsi, a. BECK BUILDING COMPANY SWEETWATER RANCH - MAIN RESIDENCE oTLIT PROJECT NO. GS06935.000-125-Rl Looking north at Main Residence - Pit A Looking east from Main Residence - Pit C A-1 ffi Soils exposed in Main Residence - Pit A Soils excavated from Main Residence - Pit A BECK BUILDING COMPANY SWEETWATER RANCH. MAIN RESIDENCE CTLIT PROJECT NO. GS06935.000-125-R1 A-2 ffir Soils exposed in Main Residence - Pit B Soils excavated from Main Residence - Pit B BECK BUILDING COMPANY SWEETWATER RANCH - MAIN RESIDENCE cTLIT PROJECT NO. cS06935.000-1 25.R1 A-3 ffi Soils exposed in Main Residence - Pit C Soils excavated from Main Residence - Pit C BECK BUILDING COMPANY SWEETWATER RANCH. MAIN RESIDENCE cTLIT PROJECT NO. GS06935.000-125-R1 A-4