20070521083230.pdfROBISON ENGINEERING, INC.
20300 t 9T" AVENuE NE
SHORELINE, WA 98155
(206) 3643343 / FAX (206) 3643363
May 8, 2007
City of Edmonds
Development Planning Services
Attn: Jenny Readwin
121 5'" Avenue North
Edmonds, WA 98020
Subject: Robison Residence Remodel
Permit Number 20061295
Insulation Alternative
Dear Jenny,
The purpose of this letter is to request approval of an alternate insulation design for the
subject residence remodel. The proposed insulation will improve the energy over the
presently permitted design.
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Proposal Replace all the insulation in the house including the undistur d existing
portions with increased R -Value insulation. New walls would beJI9" existing walls
would increase from R-6 to R-13, existing ceiling would increase from R-11 to R-21 and
new ceiling would also be R-21.
Deviation from code: The deviation from code is that code requires R-.30 insulation in
the new roof section.
Improved Total Energy Efficiency: Based on the calculations attached, the total energy
efficiency of the residence with the proposed design will be almost twice as efficient as
the permitted, code compliant design.
Motivation., Our motivation for this option is based on the limited size of the existing
rafters such that R-30 insulation cannot be easily installed. The proposed design allows
use of slightly thinner insulation, but compensates by upgrading all the insulation.
Your approval of this alternate design would be appreciated.
Sincerely,
Robison Engineering, Inc.
Mark D. RobisonUP.E.
President
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104- ✓ J
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REVII&AJOKI
MAY 09 230711
C OFDEPARTMENT
EDMONDS
17976
Robison Residence: 1010 B Avenue Permit Number: 20061295
Insulation Calculations
Original Conditions
Location
Exist Area
Existing R value
UA
Roof
1164
11
106 .
East Wall
352
6
59
North Wall
417
6
70
South Wall
333
6
56
West Wall
692
6
115
32
196
19
405
Proposed all new insulation for roof and walls
Location
Exist Area
Upgrade R Value
UA
Added Area
Upgrade R Value
UA
Roof
1164
21
55
467
21
22
East Wall
352
13
27
0
19.
0
North Wall
417
13
32
196
19
10
South Wall
333
13
26
223
19
12
West Wali
692
13
53
0
19
0
193
44
Original UA
405
New UA
238
Insulation as presently permitted
Location
Exist Area
Existing Insulation
UA
Added Area
Upgrade R Value
UA
Roof
1164
11
106
467
30
16
East Wail
352
6
59
0
19
0
North Wall
417
6
70
196
19
10
South Wall
333
6
56
223
19
12
West Wall
692
6
115
0
19
0
405
38
Original UA
405
As Permitted
442
Proposed
238