HomeMy WebLinkAboutObservation of ExcavationKaaar 8 Aneclaim lac. • 5020 County Road 154
'� Geote&eOcal and Materials Engineers Glenwood Springs, Co 81601
and EnWonrnental Scientists phone: (970) 945-7988
email: kagienwood@kumarusa.com
M Employee Owned Company
OMm Locations: Denver (tiC), Parker, Colorado Springs, Fort Collins, Glenwood Springs, and Summit County, Colorado
June 18, 2025
James Martinez
132 Lasso Lane
Silt, Colorado 81652
'cmtzoonstruction live.com
Project No. 25-7-377
Subject: Observation of Excavation, Proposed Residence, Lot 6, Block 2, The Fairways,
Battlement Mesa, 52 Hogan Circle, Garfield County, Colorado
Dear James:
As requested, a representative of Kumar & Associates observed the excavation at the subject
site on June 17, 2025 to evaluate the soils exposed for foundation support. The findings of our
observations and recommendations for the foundation support are presented in this report. The
services were performed in accordance with our agreement for professional engineering services
to James Martinez dated May 29, 2025.
The proposed residence will be a one- and two-story wood frame structure with an attached
garage. The proposed residence has been designed to be supported on spread footings sized
for an allowable bearing pressure of 1,500 psf with a risk of foundation movement.
At the time of our visit to the site, the foundation excavation had been cut in 2 levels from 1 to 3'/2
feet below the adjacent ground surface. The soils exposed in the bottom of the excavation
consisted of medium stiff, sandy silt. Results of swell -consolidation testing performed on samples
taken from the site, shown on Figure 1, indicate the soils are compressible under conditions of
loading and wetting. No free water was encountered in the excavation and the soils were slightly
moist to moist.
Considering the conditions exposed in the excavation and the nature of the proposed
construction, spread footings placed on the undisturbed natural soil designed for an allowable soil
bearing pressure of 1,500 psf should be adequate for support of the proposed residence. There
is some risk of settlement if the bearing soils were to become wetted and precautions should be
taken to prevent wetting. Footings should be a minimum width of 18 inches for continuous walls
and 2 feet for columns. Loose disturbed soils in footing areas should be removed and the bearing
level extended down to the undisturbed natural soils. Exterior footings should be provided with
adequate soil cover above their bearing elevations for frost protection. Continuous foundation
wails should be heavily reinforced top and bottom to span local anomalies such as by assuming
an unsupported length of at least 14 feet. Foundation walls acting as retaining structures should
also be designed to resist a lateral earth pressure based on an equivalent fluid unit weight of at
least 55 pcf for on -site soil as backfill. A perimeter foundation drain should be provided to prevent
temporary buildup of hydrostatic pressure behind the basement walls and prevent wetting of the
lower level. An impervious membrane, such as 20 mil PVC should be provided below the drain
gravel in a trough shape and attached to the foundation wall with mastic to prevent wetting of the
bearing soils. Structural fill placed within floor slab areas can consist of the on -site soils
compacted to at least 95% of standard Proctor density at a moisture content near optimum.
James Martine= Project No. 25-7-377
June 18, 2025 Page 2
Backfill placed around the structure should be compacted and the surface graded to prevent
ponding within at least 10 feet of the building. Landscape that requires regular heavy irrigation,
such as sod, and sprinkler heads should not be located within 10 feet of the foundation.
The recommendations submitted in this letter are based on our observation of the soils exposed
within the foundation excavation and do not include subsurface exploration to evaluate the
subsurface conditions within the loaded depth of foundation influence. This study is based on the
assumption that soils beneath the footings have equal or better support than those exposed. The
risk of foundation movement may be greater than indicated in this report because of possible
variations in the subsurface conditions. In order to reveal the nature and extent of variations in
the subsurface conditions below the excavation, drilling would be required. It is possible the data
obtained by subsurface exploration could change the recommendations contained in this letter.
Our services do not include determining the presence, prevention or possibility of mold or other
biological contaminants (MOBC) developing in the future. If the client is concerned about MOBC,
then a professional in this special field of practice should be consulted.
If you have any questions or need further assistance, please call our office.
Sincerely,
Kumar & Associates, IG/S;
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James H. Parsons, P. ' 6L'(/Z3/75
Rev. by. SLP
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attachments Figures 1 and 2 — SwelWonsolidabon Test Results
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SAMPLE OF: Sandy Silt and Clay
FROM: Footing Grade — Norlh
WC= 12.1 X,DD=90pcf
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ADDITIONAL COMPRESSION
UNDER CONSTANT PRESSURE
DUE TO WETTING
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25-7-377 Kumar & Associates SWELL —CONSOLIDATION TEST RESULTS Fig