Tommy Moore Engineering Letter___________________________________________________________________________________________
Domus Structural Engineering, LLC
P.O. Box 560
Broomfield, CO 80038
530-864-7055
projects@domusstruc.com
To: BlueRavenSolar
1403NorthResearchWay,BuildingJ
Orem,UT.84097
Subject: CertificationLetter
MooreResidence
9224ConineStSE
Yelm,WA.98597
ToWhomItMayConcern,
DesignCriteria:
භ ApplicableCodes=2021IBC/IRC,ASCE7Ͳ16
භ RoofDeadLoad=7psf(MP1)
භ RoofLiveLoad=20psf
භ WindSpeed=110mph(Vult),ExposureC
භ
භ
Sincerely,
JohnCalvert,P.E.
ProjectEngineer
Thescopeofthisreportisstrictlylimitedtoanevaluationofthefastenerattachment,underlyingframingandsupporting
structureonly.Theattachmentstotheexistingstructurearerequiredtobeinastaggeredpatterntoensureproperdistribution
ofloading.Allpanels,rackingandhardwareshallbeinstalledpermanufacturerspecificationsandwithinspecifieddesign
limitations.Allwaterproofingshallbeprovidedbythemanufacturer.DomusStructuralEngineeringassumesnoresponsibility
formisuseorimproperinstallationofthesolarPVpanelsorracking.
Pleasecontactmewithanyfurtherquestionsorconcernsregardingthisproject.
Attachment:2Ͳ#14WoodScrewswith1.75inchmin.embedment
depth,atspacingshownabove.
January14,2025
Theroofstructureof(MP1)consistsofcompositionshingleonroofplywoodthatissupportedbypreͲmanufacturedtrussesthat
arespacedat@24"o.c..Thetopchords,slopedat23degrees,are2x4sections,thebottomchordsare2x4sectionsandtheweb
membersare2x4sections.Thetrussmembersareconnectedbysteelgussetplates.Themaxunsupportedprojectedhorizontal
topchordspanisapproximately7'Ͳ0''.
Theexistingroofframingsystemof(MP1)isjudgedtobeadequatetowithstandtheloadingimposedbytheinstallationofthe
solarpanels.Noreinforcementisnecessary.
RoofSnowLoad=20psf
Thespacingofthesolarstandoffsshouldbekeptat72"o.c.forlandscapeand48"o.c.forportraitorientation,withastaggered
patterntoensureproperdistributionofloads.
AjobsiteobservationoftheconditionoftheexistingframingsystemwasperformedbyanauditteamofBlueRavenSolarasa
requestfromDomusStructuralEngineering.Allreviewisbasedontheseobservationsandthedesigncriterialistedbelowand
onlydeemedvalidifprovidedinformationistrueandaccurate.
Ontheabovereferencedproject,theroofstructuralframinghasbeenreviewedforadditionalloadingduetotheinstallationof
thesolarPVadditiontotheroof.Thestructuralreviewonlyappliestothesectionoftheroofthatisdirectlysupportingthesolar
PVsystemanditssupportingelements.Theobservedroofframingisdescribedbelow.Iffieldconditionsdiffer,contractorto
notifyengineerpriortostartingconstruction.
Moore Yelm WA 1
Digitally signed by
John Calvert
Date: 2025.01.15
06:43:32 -07'00'
___________________________________________________________________________________________
Domus Structural Engineering, LLC
P.O. Box 560
Broomfield, CO 80038
530-864-7055
projects@domusstruc.com
20.0 psf
(ASCE7 - Eq 7-1)
1 (ASCE7 - Table 7-2)
1 (ASCE7 - Table 7-3)
1
20.0 psf
(ASCE7 - Eq 7-2)
1.00
20.0 psf
3.26 psf
3.0 psf
4.00 ft
6.08 ft
24.33 sft
73 lb
4.00 psf
2.00 psf
0.73 psf
0.00 psf (Ceiling Not Vaulted)
0.27 psf
7.0 psf
7.6 psf
PV Dead Load = 3 psf (Per Blue Raven Solar)
DL Adjusted to 23 Degree Slope
Point Loads of Standoffs
Miscellaneous
Vaulted Ceiling
Total Roof DL (MP1)
Roof Live Load = 20 psf
Roof Plywood
Roof Dead Load (MP1)
Composition Shingle
Note: Roof live load is removed in area's covered by PV array.
Roof Snow Load Calculations
pg = Ground Snow Load =
Ce = Exposure Factor =
pf = 0.7 Ce Ct I pg
Ct = Thermal Factor =
I = Importance Factor =
Cs = Slope Factor =
Standoff Tributary Area =
ps = Cspf
ps = Sloped Roof Snow Load =
pf = Flat Roof Snow Load =
DL Adjusted to 23 Degree Slope
Gravity Loading
PV System Weight
Weight of PV System (Per Blue Raven Solar)
X Standoff Spacing =
Y Standoff Spacing =
Note: PV standoffs are staggered to ensure proper distribution of loading
2x4 Top Chords @ 24"o.c.
Moore Yelm WA 2
___________________________________________________________________________________________
Domus Structural Engineering, LLC
P.O. Box 560
Broomfield, CO 80038
530-864-7055
projects@domusstruc.com
110 mph
C
Gable Roof
23 degrees
20 ft
21.3 ft
0 ft
(Eq. 26.10-1)
0.90 (Table 30.3-1)
1.00 (Fig. 26.8-1)
0.85 (Table 26.6-1)
1.00
110 mph (Fig. 26.5-1A)
II (Table 1.5-1)
qh = 23.75 psf
Zone 1 Zone 2 Zone 3 Positive
ya =0.67 0.77 0.80 0.67
GCp =-1.45 -2.41 -3.10 0.44 (Fig. 30.3)
Uplift Pressure =-23.1 psf -44.1 psf -58.8 psf 7.1 psf (Eq. 29.4-7)
ASD Uplift Pressure =-13.8 psf -26.4 psf -35.3 psf 9.6 psf
X Standoff Spacing = 4.00 ft 4.00 ft 2.67 ft
Y Standoff Spacing = 6.08 ft 3.04 ft 3.04 ft
Tributary Area = 24.33 sqft 12.17 sqft 8.11 sqft
Dead Load on attachment = 73 lb 37 lb 24 lb
Footing Uplift (0.6D+0.6W) = -293 lb -300 lb -272 lb
Zone 1 Zone 2 Zone 3 Positive
ya =0.69 0.79 0.80 0.69
GCp =-1.49 -2.48 -3.20 0.46 (Fig. 30.3)
Uplift Pressure =-24.4 psf -46.6 psf -60.8 psf 7.6 psf (Eq. 29.4-7)
ASD Uplift Pressure (0.6W)=-14.7 psf -28.0 psf -36.5 psf 9.6 psf
X Standoff Spacing = 6.00 ft 6.00 ft 4.00 ft
Y Standoff Spacing = 3.50 ft 1.75 ft 1.75 ft
Tributary Area = 21.00 sqft 10.50 sqft 7.00 sqft
Dead Load on attachment = 63 lb 32 lb 21 lb
Footing Uplift (0.6D+0.6W) = -270 lb -275 lb -243 lb
-300 lb
425 lb
Therefore, OK
Fastener =2 - #14 Wood Screws
Number of Fasteners = 2
Embedment Depth = 1.75 in.
Pullout Capacity Per Inch = 150 lb
Fastener Capacity = 525 lb
w/ F.S. of 1.5 & DOL of 1.6= 560 lb
Therefore, OK
Wind Calculations
Maximum Design Uplift =
Design Wind Pressure Calculations
qh = 0.00256 * Kz * Kzt * Kd * Ke * V^2
Kz (Exposure Coefficient) =
Kzt (Topographic Factor) =
Wind Speed
Exposure Category
Roof Shape
Roof Slope
Effective Wind Area
PerASCE7Ͳ16ComponentsandCladding
Input Variables
Fastener Capacity Check
Mean Roof Height
Ground Elevation
Kd (Wind Directionality Factor) =
560 lb capacity > 300 lb demand
Ke (Ground Elevation Factor) =
V (Design Wind Speed) =
Risk Category =
Standoff Uplift Calculations-Portrait
Standoff Uplift Calculations-Landscape
Standoff Uplift Check
Standoff Uplift Capacity =
425 lb capacity > 300 lb demand
Moore Yelm WA 3
___________________________________________________________________________________________
Domus Structural Engineering, LLC
P.O. Box 560
Broomfield, CO 80038
530-864-7055
projects@domusstruc.com
(MP1)PASS
Dead Load 7.6 psf
PV Load 3.3 psf
Snow Load 20.0 psf
Governing Load Combo = DL + SL
Total Load 30.9 psf
Fb (psi) = f'b x Cd x Cf x Cr (NDS Table 4.3.1)
900 x 1.15 x 1.5 x 1.15
Allowed Bending Stress = 1785.3 psi
(wL^2) / 8
= 378.0791 ft#
= 4536.95 in#
Actual Bending Stress = (Maximum Moment) / S
= 1481.5 psi
L/180 (E = 1600000 psi Per NDS)
= 0.466 in
Deflection Criteria Based on =
(w*L^4) / (185*E*I)
=
= L/519 > L/180 Therefore OK
Allowed Deflection (Live Load) =L/240
0.35 in
(w*L^4) / (185*E*I)
L/800 > L/240 Therefore OK
Member Area = Fv (psi) = 180 psi (NDS Table 4A)
Allowed Shear = Fv * A = Max Shear (V) = w * L / 2 = 216 lb
Check Bending Stress
(True Dimensions)
Continuous Span
0.162 in
0.105 in
Member Properties
Member Size
2x4
S (in^3)
3.06 DF#2
Member Spacing
@ 24"o.c.
Maximum Moment =
Check Deflection
I (in^4)
5.36
Lumber Sp/Gr
Actual Deflection (Live Load) =
Allowed Deflection (Total Load) =
Actual Deflection (Total Load) =
Allowed > Actual -- 83% Stressed -- Therefore, OK
945 lb
Allowed > Actual -- 22.9% Stressed -- Therefore, OK
5.3 in^2
Check Shear
w = 62 plf
2x4 Top Chords @ 24"o.c.
Member Span = 7' - 0"
Framing Check
Moore Yelm WA 4
___________________________________________________________________________________________
Domus Structural Engineering, LLC
P.O. Box 560
Broomfield, CO 80038
530-864-7055
projects@domusstruc.com
Level Area Weight (psf) Weight (lb)
Roof 2010 sf 7.6 psf 15284 lb
Ceiling 2010 sf 6.0 psf 12059 lb
Wood Siding 100 ft 5.0 psf 2000 lb (8'-0" Wall Height)
Int. Walls 100 ft 6.4 psf 2560 lb
31902 lb
3.0 psf
213 sf
639 lb
3190 lb
639 lb
2.0%
Lateral Check
3190 lb > 639 lb, Therefore OK
Existing Weight of Effected Building
Existing Weight of Effected Building
Proposed Weight of PV System
Weight of PV System (Per Blue Raven Solar)
Approx. Area of Proposed PV System
Approximate Total Weight of PV System
10% Comparison
10% of Existing Building Weight (Allowed)
Approximate Weight of PV System (Actual)
Percent Increase
Moore Yelm WA 5
___________________________________________________________________________________________
Domus Structural Engineering, LLC
P.O. Box 560
Broomfield, CO 80038
530-864-7055
projects@domusstruc.com
Appendix A: General Notes
GENERAL
Ɣ The contractor shall verify all dimensions, property setbacks, AHJ/HOA CC&R's, elevations and site conditions before
starting work and shall notify Domus Structural Engineering, LLC of any discrepancies.
Ɣ All report conclusions represent Domus Structural Engineering, LLC's best professional judgment based upon industry
standards.
Ɣ Resolve any conflicts on the drawings with Domus Structural Engineering, LLC before proceeding with construction.
Ɣ The design criteria used for this project & listed on the first page of the report is based on the engineers best judgement
and/or provided by the ATC council. AHJ specific requests may differ. Please contact our team if the design criteria needs to
be modified.
Ɣ A site visit was not physically conducted by Domus Structural Engineering, LLC. The accompanying calculations and
certification are provided with the understanding that the site building and construction standards meet an acceptable level of
industry standards. It shall be the contractors responsibility to identify any irregularities such as inconsistent framing
conditions, water damage, fire damage, cracked, split or noticeably deflecting framing members.
Ɣ Domus Structural Engineering, LLC is not responsible for enforcing safety measures or regulations. The contractor shall
design, construct, and maintain all safety devices including shoring and bracing, and shall be solely responsible for
conforming to all local, state and federal safety and health standards, laws and regulations. The contractor shall take
necessary precautions to maintain and insure the integrity of the structure during construction. If a lawsuit is filed by one of
the contractor's or subcontractor's employees, or any one else, the contractor will indemnify, defend and hold the owner and
Domus Structural Engineering, LLC harmless of any and all such claims.
Ɣ Any and all waterproofing shall be provided by the contractor. Domus Structural Engineering, LLC is not responsible for
waterproofing.
Ɣ All hardware shall be installed per manufacturer specifications and within specified design limitations. Domus Structural
Engineering, LLC assumes no responsibility for incorrectly installed hardware or hardware installed outside of the
manfacturer specifications.
USER RELIANCE
Ɣ Domus Structural Engineering, LLC was engaged by Blue Raven Solar (Client) to perform this assessment. This report and
the information therein, are for the exclusive use of the Client. This report has no other purpose and shall not be relied upon,
or used, by any other person or entity without the written consent of Domus Structural Engineering, LLC. Third parties that
obtain this report, or the information within shall have no rights of recourse or recovery against Domus Structural
Engineering, LLC, its officers or employees.
ROOF MOUNTED ARRAYS
Ɣ If an analysis of a supporting stucture is included in our scope of work, the structural assessment only applies to the section
of the roof that is directly supporting the proposed solar PV system.
Ɣ No structural members can be cut for conduit, etc., unless specifically shown. Obtain prior written approval for installation of
any additional conduit, etc.
Ɣ It is assumed that a standard quality of construction care was used to construct the original building. It shall be the
contractors responsibility to field verify any and all framing members supporting the proposed PV array are in adequate
condition. The contractor shall field inspect for sub-standard construction means, signs of dry rot, mold, fire damage, etc. and
notify engineer if any compromised material is found on site prior to starting construction.
Ɣ It is assumed that there have been no additional loads (HVAC or MEP equipment, additional layers of roofing, etc) added to
the building over the course of the structure's histroy. The contractor and/or client shall verify this with the property owner
and notify Domus Structural Engineering, LLC if additional load has been added to the structure already.
Ɣ Flexible utility connections must be used at any building seismic joint.
Ɣ Care should be taken to ensure that PV arrays do not preclude drainage of rain water.
Ɣ Unless otherwise noted, construction material shall be evenly distributed if placed on framed floors or roofs. Loads shall not
exceed the allowable loading for the supporting members and their connections.
Ɣ All lags or wood screws at the roof shall be stainless steel and installed withing the middle 1/3 of the dimensional width of the
framing members.
Ɣ All fasteners shall be a minimum of 6" away from any truss panel or hinge joints, truss plates and/or member ends. Field
verify location of fasteners prior to starting construction. All fasteners shall be pre-drilled to avoid splitting existing lumber.
Ɣ Domus Structural Engineering, LLC is not responsible for downslope effects of snow shedding or sliding off of the PV array
nor any damage to downslope decks, roofs, walkways, landscaping, automobiles, pets, people, etc.. If snow guards are
requested by the customer, notify Domus Structural Engineering, LLC.
Moore Yelm WA 6