HomeMy WebLinkAbout621 SEDGWICK DR - CORRESPONDENCE - 5/29/1998May 29, 1998
Melody Homes
11031 Sheridan Boulevard
Westminster, Colorado 80020
Attn: Mr. Shawn Weiman
Re: Lot 86, Ridgewood Hills PUD Second Filing
621 Sedgwick Drive
Fort Collins, Colorado
Project No. 20985076
Reference: Geotechnical Engineering Report
Ridgewood Hills PUD Second Filing
Project No. 20965040, Dated April 19, 1996
Ireforacon
301 N. Howes • P.O. Box 503
Fort Collins, Colorado 80521-0503
(970) 484-0359 Fax: (970) 484-0454
Terracon has completed a geotechnical engineering exploration for the proposed residence to be
constructed on the above -referenced lot. One test boring was drilled in the approximate center of
the lot and a relatively undisturbed sample was obtained for laboratory testing and analysis. The
materials tested on the site are classified as low swelling based on the Colorado Association of
Geotechnical Engineers (CAGE) criteria.
Geotechnical recommendations for design of foundations and other earth connected phases of this
residence were developed based on the referenced exploration for the overall subdivision, and the
borings drilled in this and adjacent lots. Terracon's recommendations are summarized below.
Foundation Recommendations
Spread footing foundations bearing upon undisturbed subsoils, recompacted native soils and/or
bedrock are recommended for support of the proposed structure.
Basement Construction
Groundwater was not encountered on this lot to the depth explored. Bedrock was encountered to
a depth of 13 feet. Full -depth basement construction is considered acceptable, provided a
complete dewatering system is provided around the lower basement area.
The dewatering system should contain a drain constructed around the exterior perimeter of the
basement foundation and sloped at a minimum 1/8 inch per foot to a suitable outlet, such as a
sump or area drain.
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Terracon
Melody Homes
Page 2
Project No. 20985076
The drainage system should consist of a properly sized perforated pipe placed in a trench at least
12 inches in width. The pipe should be placed on filter fabric. Gravel should be placed around the
pipe and extend a minimum of 6 inches above the pipe. The gravel should be covered with
drainage fabric prior to placement of foundation backfill.
Floor Slab Design and Construction
The variability of the existing soils at approximate slab subgrade elevation could result in
differential movement of floor slab -on -grade should the expansive soils increase in moisture
content. Based on the CAGE criteria, the subsoils at the site have a slab performance risk
category of 'low". Movement not likely to exceed up to 2 inches or more is estimated if the subsoils
below slabs become wetted for a zone of approximately 10 feet below the basement. Slab -on -
grade construction for the basement of this residence should perform in accordance with the above
criteria. The homeowner should be aware of the risk of this slab movement and should take this
into account prior to purchasing the residence.
Surface Drainage
Positive drainage should be provided during construction and maintained throughout the life of the
proposed residence. Planters and other surface features which could retain water in areas adjacent
to the building or pavements should be sealed or eliminated.
In areas where sidewalks or paving do not immediately adjoin the structure, we recommend that
protective slopes be provided with a minimum grade of approximately 10 percent for at least 10
feet from perimeter walls where possible and at a minimum approximately 10 percent for at least 5
feet from perimeter walls. Backfill against footings, exterior walls and in utility and sprinkler line
trenches should be well compacted and free of all construction debris to reduce the possibility of
moisture infiltration.
Downspouts, roof drains or scuppers must discharge into splash blocks or extensions when the
ground surface beneath such features is not protected by exterior slabs or paving. Sprinkler
systems should not be installed or irrigate within 5 feet of foundation walls.
Terracon
Melody Homes
Page 3
Project No. 20985076
Construction Observation
The following observations are recommended during construction:
• Footing sizes and void form placement;
• Wall steel;
• Perimeter drain; and
• Basement slab
We appreciate the opportunity to be of service to you on this phase of your project. If you have
any questions concerning this letter report, or if we may be of further service to you, please do not
hesitate to contact us.
Sincerely,
TERRACON
Doug Leafgreii
Staff Geologist
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William J. Attwooll,
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Office Manager
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