HomeMy WebLinkAboutExcavation ObservationJuly 11, 2012
Pete Welles
5343 County Road 100
Carbondale, Colorado 81623
Job No. 112 228A
Subject: Observation of Excavation, Proposed Guest House, 5343 County Road
100, South of Rimledge Road, Garfield County, Colorado
Dear Mr. Welles:
As requested, a representative of Hepworth-Pawlak Geotechnical, Inc. observed the
excavation at the subject site on July 9, 2012 to evaluate the soils exposed for foundation
support. The findings of our observations and recommendations for the foundation
design are presented in this report. The services were performed in accordance with our
agreement for professional engineering services to you, dated July 5, 2012.
The guest house is located just northwest of the existing house and north of the large spa
area. The guest house will be a 2 story wood frame structure with a slab -on -grade main
floor. Foundations were designed for an assumed allowable soil bearing pressure of
2,000 psf
At the time of our visit to the site, the foundation excavation had been cut in one level
from 21/2 to 3 feet below the adjacent ground surface. The soils exposed in the bottom of
the excavation consisted of compacted I'/ -inch road base. We understand that the
underling natural soils consist of basalt rocks in a clayey sandy silt matrix, similar to that
exposed in the sides of the excavation. The north side of the excavation was the site of a
portion of the existing septic field. Bill Vezzoso, the excavator, stated that he had
removed the old septic field fill which extended down about 2 feet below design footing
grade, and compacted the road base in 8 -inch lifts back to the current grade. The south
side of the excavation had up to 1 foot of compacted road base. At the time of our site
visit, we observed the road base fill was nearly completed to footing grade and was being
wetted down regularly and compacted with several passes of a remote-controlled double
drum trench compactor. The compaction procedures appeared to be adequate. At the
Pete Welles
July 11, 2012
Page 3
ground subsidence at this site is low and similar to other lots in the area but the owner
should be aware of the potential for sinkhole development.
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,
HEPWORTH -- PAWLAK GEOTCHNICAL, INC.
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Roaring Fork Builders— Dan Johns clanii%roarin! tbikhuilders,ct,in
Job No. 112 228A
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