HomeMy WebLinkAbout09.1 - - Letter from EGA Consultants - 5/17/2011co7asiilt�t�zts
CITY OF COSTA MESA
77 Fair Drive 2M Floor
Costa Mesa, CA 92626
R E Ems'-EiVL; b;
CITY CLERK
2011 MAY -9 AM II. 4G
C'111::' GF COSTA A MESA
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Attention: Rebecca Robbins, Building Planner
1iIN
engineering
geotechnical
applications
April 9, 2011
Project No. TJ580.1
Subject: Project Consultation -Approved Pier and Grade Beams, Setbacks and Drainage
FOR NEW REAR YARD DECK EXTENSION and ADDITIONS
AT 1151 GLENEAGLES TERRACE
COSTA MESA, CALIFORNIA
Application No. ZA-09-37- Al
Reference: "Geotechnical Investigation For Proposed Residential Additions - Rear Yard Deck Extension at
1151 Gleneagles Terrace, Costa Mesa, California," by EGA Consultants, LLC, dated November
11, 2009.
Dear Ms. Robbins,
In accordance with the 2010 CBC and the City of Costa Mesa building requirements, we are
submitting this Compliance Report to certify that we have observed and approved the caisson
drilling operation as well as the grade beam and foundation trenches and hereby verify that
such work is in conformance with the approved Soils Report (referenced above).
The new rear yard deck, bedroom/bathroom addition and fireplace foundations are supported
by the drilled, cast -in-place caissons and grade beams. On December 8, through December 9,
2010, a total of four (4), 24" diameter caisson boreholes were drilled by Peter Drilling, Inc. each
to total depths of 15 feet below lowest adjacent slope grade. Representatives from our firm
inspected and confirmed that the four boreholes extend a minimum 12 ft. into competent native
materials. The caisson embedments meet or exceed the specifications outlined in the above -
referenced Soils Report and the Foundation Plan by Shucri Yaghi, Consulting Engineers (dated
July 9, 2010 and revised on August 6, 2010 and on September 30, 2010).
Note: The new construction locations in relation to the rear yard, southwest -facing slope are as
follows:
1. New bedroom/bathroom foundation setback 4 ft. 3 inches from top of slope.
2. New deck fireplace foundation extends 4 ft. past the top of slope.
The above foundation elements are tied -in and supported by the new pier and grade beam
system. Therefore, from a geotechnical standpoint there is -no added surcharge to the slope.
The underpinning and new construction is approved from a geotechnical standpoint.
375-C Monte Vista Avenue - Costa Mesa, CA 92627 - (949) 642-9309 - FAX (949) 642-1290
We recommend installing additional rain gutters and down spouts along the residence
perimeters. All downspouts should be tight -lined into area drains. All drains should be directed
to a suitable discharge, such as the curb -face at Aviemore Terrace. Under no circumstances
should water be allowed to pond adjacent to the residence slabs, standing structures, and the
rear slope.
Based on the findings of our geotechnical investigation and our continuous observations and
testing during the pier, grade beam, foundation and steel doweling phases, the on-site new
construction will not impact the geologic stability/safety of the subject or surrounding sites.
Geologic hazards such as landsliding, settlement, or slippage are not present or future factors
at the subject or adjacent sites, provided the proposed drainage diverts surface and roof gutter
runoff to a suitable outlet, away from the slope and foundations.
This opportunity to be of service is appreciated. If you have any questions, please call.
Very truly yours,
EG Consultants, LLC
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DAVID A. WORTHINGTON CEG 2124
Principal Engineering Geologist
Copies: (2) Addressee
(1) Mr. William Lowe, Homeowner
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GEOTECHNICAL CONSULTATION - Lowe Residence Rear Yard Additions
1151 Gleneagles Ter, Costa Mesa, CA
Project No. TJ580.1
April 9, 2011 Page 2 of 2
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