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Home My WebLink About2144 Yearling Dr - Special Inspections/Engineering - 09/30/2013Y A. e Geotechnical and Environmental Consultants D R Horton 9555 South Kingston Court, Suite 200 Englewood, Colorado 80112-5943 Attention: Mr. Tim Karns 2180 South Ivanhoe Street, Suite 5 Denver, Colorado 80222-5710 303-759-8100 Fax 303-756-2920 www.agwassenaar.com September 30, 2013 rLN� I J.,kr`(;, r o) 1Y. Subject: Soil and Foundation Study Proposed Residential Structure Lot 12, Block 18 ort Codehill, Filing 2 Fort Collins, Colorado Project Number 131389 =1� Purpose As requested, we have performed a soil and foundation study at the subject site. The purpose of our study was to observe subsurface conditions encountered and to recommend geotechnical design criteria for the design and construction of the foundation for the proposed residence. Additionally, we reviewed partial "Construction Observation and Testing" reports (Earth Engineering Consultants, LLC, Project Number 1124098, dated December 28, 2012 and May 1, 2013) as a portion of our analysis. This letter presents a summary of our findings and recommendations. Subsurface Conditions The field exploration included drilling a 4-inch diameter auger boring near the center of the lot in the upper level to a depth of approximately 29'/z feet. The subsurface materials encountered consisted of: 0' to 17' 17' to 24' 24' to 291/2' Date of drilling: Depth to water: Laboratory Testing Fill, clay, stiff, silty, sandy, slightly gravelly, moist, mottled brown Clay, medium stiff, silty, sandy, moist, light brown to reddish brown Sand and Gravel, medium dense to dense, silty, moist to wet, brown to reddish brown July 23, 2013 27 feet at the time of drilling Wet Caved at 26'h feet 2 days after drilling Samples obtained during drilling were returned to the laboratory. They were visually classified and testing was assigned to selected samples in an effort to evaluate the engineering properties of the subsurface materials encountered. Site specific laboratory swell/consolidation tests exhibited no to low measured swell (0.4% at a depth of 4 feet and 0.0% at a depth of 19 feet) upon an increase in No Text No Text No Text No Text No Text No Text No Text D R Horton Project Number 131389 September 30, 2013 Page 7 2. The ground surFace surrounding the e�erior of the foundation should be maintained in such a manner as to provide for positive surFace drainage away from the foundation. At completion of construction,we recommend a minimum fall away from the foundation of 6 inches in the first 5 feet. This slope should be continuous across the backfill zone. 3. Backfill around the foundation should be moistened and compacted in such a manner as to reduce future settlement. Areas which settle should be fiiled as soon as possible in order to maintain positive drainage away from the foundation. 4. If lawn edging is used around the exterior of the foundation, it should be constructed in a manner to prevent ponding of surtace water in the vicinity of the backfill soils. 5. All drainage swales should be constructed and maintained a minimum of 5 feet away from the foundation on side yards and 15 feet away from the foundation on back and front yards. Drainage swales should maintain a slope of at least 2% off of the lot. Swales must not be blocked by fences, landscaping, paths or other Homeowner installed items. 6. Roof downspouts and drains should discharge well beyond the limits of foundation backfill. 7. Watering adjacent to the foundation should be reduced as much as practical. Landscaping which requires excessive watering should not be located within 5 feet of foundation walls. Main sprinkler lines, zone control boxes and drains should be located outside the limits of the foundation backfill. Sprinkler heads should be positioned such that the spray does not fall within 5 feet of foundation walls. 8. Plastic membranes should not be used to cover the ground surface immediately surrounding the foundation. These membranes tend to trap moisture and prevent normal evaporation from occurring. We recommend the use of a weed suppressant geotextile fabric. Limifafions We believe the professional judgments expressed in this report are consistent with that degree of skill and care ordinarily exercised by practicing design professionals pertorming similar design services in the same locality, at the same time, at the same site and under the same or similar circumstances and conditions. No other warranty, express or implied, is made. The location of the test boring drilled and the laboratory testing performed for this study were designed to obtain a reasonably accurate picture of subsurface conditions for design purposes. Variations in subsurface conditions not indicated by the boring are possible and expected. Therefore, we should be retained D R Horton Project Number 131389 September 30, 2013 Page 8 to observe the foundation excavation and construction in order to verify or revise our recommendations. If unexpected subsurface conditions are observed by others during construction, we should be called to review our recommendations. This report was prepared for the exclusive use of our Client for the sole purpose of providing geotechnical design criteria for the subject structure based upon the existing site conditions as encountered. The conclusions and recommendations contained in this report shall not be considered valid for use by Others without written authorization from A. G.Wassenaar, Inc. In addition,the state of practice in geotechnical engineering is constantly evolving. Therefore, findings presented in this report should be reviewed and revised, if necessary, prior to actual construction. If we can be of further service in discussing the contents of this letter or in analysis of the proposed structure from the soil and foundation viewpoint, please call our office. Sincerely, A. G. WASSENAAR, INC. �PppO REg�ST po°�N ANlV�F��,� . ^ O Ka hleen A. Noonan, P.E. ' °'` y° Senior Engineer � �� NUMBER �o 0 32156 = o,�°e9_,A-1'�,e��c,Q Reviewed by: Fss��A�ENG�� - Keith D. Seaton, P.E. Senior Engineer KAN/KDS/lia Attachments: Figures 1, 2, and 3 Statement of Services ' A.G. Wassenaar • Geotechnical end Environmenlal Consultants (�i• NOTES: 1. DRAIN MUST SLOPE TO A POSITIVE GRAVITY OUTLET AND/OR TO SUMP WHERE WATER CAN BE REMOVED BY PUMPING � ///� 2. SLOPE BOTTOM OF TRENCH AND PIPE AT A � �� MINIMUM OF 1/8"PER FOOT(i.e.1 /o) �� /�� OR AS APPROVED BY THE GEOTECHNICAL ENGINEER 3. 41NCH DIAMETER RIGID PERFOR,4TED PVC PIPE(ASTM D2729 MINIMUM SCHEDULE 20),OR FOUNDATION SUBSTITUTE APPROVED BY GEOTECHNICAL ENGINEER WALL 4. GRAVEL SPECIFICATION:2"MINUS WASHED ROCK/GRAVEL,POORLY GRADED WITH NO MORE THAN 30°/a PASSING THE 3/8"SIEVE AND NO MORE THAN 10%PASSING THE#4 SIEVE,OR AS APPROVED BY THE GEOTECHNICAL ENGINEER MINIMUM 10 MIL POLYETHYLENE BARRIER,OR gACKFILL EQUIVALENT APPROVED BY GEOTECHNICAL ENGINEER.ATTACH TO WALLAFfER DAMPPROOFING AND EXTEND AT LEAST 1 FOOT UP ON WALL AND BENEATH FLOW LINE OF PIPE. NON-WOVEN GEOTEXTILE FILTER FABRIC (MIRAFI 140N OR E�UIVALENTAPPROVED BY GEOTECHNICAL ENGINEER)PLACED OVER ENTIRE WIDTH OF DR41N GRAVEL. FOUNDATION VOID SPACE � DRAIN GRAVEL(SEE NOTE#4). FILL ENTIRE TRENCH WITH GRAVELAND EXTEND TO TOP OF VOID. MINIMUM GRAVEL COVER OF 4"IS REQUIRED. SLIP JOINT , d CONCRETE SfAB �.:;;Q,: .. "'" �¢Q:�:•�;,••9: /o/Uo �o/ � �/ �/ �/ o a:�-:��:.�.:�::e.:o:.,;. � r� r�/ii�viii� iir� iir� iii� o:• � •:o:;.. .,�..�: .,�:" .•. DRAIN PIPE-(SEE NOTES#2&3 �" '�� AT LOCATION OF HIGH POINT, '�'�' � � ESTABLISH BOTTOM OF DR,41N DRILLED PIER PIPE AT LEAST 8"BELOW BOTTOM OF VOID � � ��MINIMUM EXTEND POLYETHYLENE TO OUTSIDE EDGE OF BOTTOM OF TRENCH PIER FOUNDATION PIER-3 EXT SOG 7YPICAL EXTERIOR DRAIN DETAIL SEPTEMBER 2007 FIGURE 1