HomeMy WebLinkAbout2400 Coventry Ct - Correspondence/Solar - 12/05/2016i
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December 5, 2016
To: Ecomark Solar
4665 Paris St. g300-C
Denver, CO.80239
Subject: Certification Letter
Palmer Residence
2400 Coventry Ct.
Ft. Collins, CO. 80526
To Whom It May Concern,
Domus Structural Engineering, LLC
1210 Birch Street
Broomfield, CO 80020
303-466-3014
Domusstructural@gmaii.com
by John
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-0Too'
A jobsite observation of the condition of the existing framing system was performed by an audit team of Ecomark Solar as a
request from Domus Structural Engineering. All review is based on these observations and the design criteria listed below and
only deemed valid if provided information is true and accurate.
On the above referenced project, the roof structural framing has been reviewed for additional loading due to the installation of
the solar PV addition to the roof. The structural review only applys to the section of the roof that is directly supporting the solar
PV system and its supporting elements. The observed roof framing is described below. If field conditions differ, contractor to
notify engineer prior to starting construction.
The roof structure of (All MP's) consists of composition shingle on roof plywood that is supported by pre -manufactured trusses
that are spaced at @ 24"o.c.. The top chords, sloped at 27 degrees, are 2x4 sections, the bottom chords are 2x4 sections and the
web members are 2x4 sections. The truss members are connected by steel gusset plates. The max unsupported projected
horizontal top chord span is approximately 7'-4".
The existing roof framing system of (All MP's) are judged to be adequate to withstand the loading imposed by the installation of
the solar panels. No reinforcement is necessary.
The spacing of the solar standoffs should be kept at 72" o.c. for landscape and 48" o.c. for portrait orientation, with a staggered
pattern to ensure proper distribution of loads.
Design Criteria:
• Applicable Codes = 2012 IBC/IRC, ASCE 7-10, and NDS-12
• Roof Dead Load = 7 psf (All MP's)
• Roof Live Load = 20 psf
• Wind Speed = 130 mph, Exposure C, Risk Category II
• Roof Snow Load = 30 psf
• Attachments: (1) 5/16" dia lag screw with 2.25" min embedment depth, at spacing shown above.
Please contact me with any further questions or concerns regarding this project.
Sincerely,
John Calvert, P.E.
Project Engineer
61701346
Palmer Residence, Ft. Collins, CO 1
6" T H U 0 T 1) R A 1'
1:5NG t N I P RJ Nc n I'C
Gravity Loading
PV System Weight
Domus Structural Engineering LLC
1210 Birch Street
Broomfield CO 80020
303 466 3014
Domusstructural@gmail com
Weight of PV System (Per Eoomark Solar)
3 0 psf
X Standoff Spacing =
4 00 ft
Y Standoff Spacing =
2 67 ft
Standoff Tributary Area =
10 68 sft
Point Loads of Standoffs
32 lb
Note PV standoffs are staggered to ensure proper distribution of loading
Roof Live Load = 20 psf
Note Roof live load is removed in area s covered by PV array
Roof Dead Load (All MP s)
Composition Shingle
400
Roof Plywood
200
2x4 Top Chords @ 24 o c
073
Vaulted Ceding
000
Miscellaneous
027
Total Roof DL (All MP s)
7 0 psf
DL Adjusted to 27 Degree Slope
7 9 psf
(Ceding Not Vaulted)
B1701346
Palmer Residence Ft Collins CO 1
ID o n� i1 ti Domus Structurel Engmeenng LLC
�c 1210 Birch Street
�d7 T R U C' T [,I K A I� Broomfield CO 80020
=�.�-,� n G 1 1 1 1 It ,I N C, 1 I�(' 303 466 3014
Y Domusstructural@gmad com
W�nd Calculations
Per ASCE 7-30 Components and Cladding
, Input Vanables - �
in pee mp
Exposure Category C
Roof Shape GablelHip
Roof Slope 27 degrees
Mean Roof Height 20 ft
Effective Wind Area 19 3 ft
( — Design Wmd Pressure Calculahons - - - - i
m ressure =q n
qh=0 00256'Kz'Kzt`Kd'V^2 (Eq 30 3 1)
Kz(Exposure Coeffiaent)= 0 9 (Table 30 31)
Kzt(topographic factor)= 1 (Fig 26 8 1)
Kd(Wmd Direchonality Factor)= 0 85 (Table 26 61)
V(Design Wind Speed)= 130 mph (Fig 26 51A)
Risk Category= II (Table 1 51)
qh= 3310
O6*qh= 1986
� Standoff Uphft Calculahons PoRrait ,
one one one osi ive
GCp= -0 86 1 51 2 37 0 42 (Fig 30 4 1)
Uplrft Pressure= 1712 psf 29 99 psf -0710 psf 14 0 psf
X Standoff Spaang= 4 00 4 00 2 67
Y Standoff Spaang= 2 67 2 67 2 67
Tnbutary Area= 10 68 10 68 712
Footmg Uplift= 1831b 3201b 3351b
i Standoff Uphft Calculations Landscape
one one one ositive
GCp= -0 S6 1 51 2 37 0 42 (Fig 30 4 1)
Uplift Pressure= 1712 psf 29 99 psf �710 psf 10 0 psf (Mirnmum)
X Standoff Spaang= 6 00 6 00 4 00
Y Standoff Spacing= 1 67 1 67 1 67
Tnbutary Area= 10 02 10 02 6 68
FootingUplift= 1721b 3001b 3151b
, Standoff Uplift Check
aximum esign p i =
Standoff Uplift Capacity = 400 Ib
400 Ib capaaty>335 Ib demand Therefore OK
Fastener Capacity Check
as ener= ia ag
, .. �Number of Fasteners= 1
�� �+, � � t ; � " �y r g Embedment Depth=2 25
' Pullout Capaaty Per Inch= 250 Ib
Fastener Capaaty= 563 Ib
w/F S of 1 5= 376 Ib
376 Ib capaaty>335 Ib demand Therefore,OK
Palmer Residence Ft Collins CO 2