RESUB 1-Calculations+1.7.2022_2.52.44_PM+2610135Hello,
In lieu of beam calculations I referred to span tables for patio cover beams and rafters and selected
upward in lumber choices to be sure to meet or exceed requirements.
Beams span up to 11' and are supporting rafters spanning 13'. The below table calls for 4x8 or 6x8
beams, I'm using hem/fir pressure treated sandwiched 2x12's for the beams.
Table C1Manimum Bea rri Sizes (Inches)
Post
Spacing
d
1+4
h.2.1
4x4
4x4
4x4
4x4
Ax4
Ax4
4x4
4x4
4
AX4
4x4
4x4
4x4
4x4
4xA
4x4
4x4
4x4
4A
4x6
4x6
4%6
4A
4A
4x4
4x5
4x6
4x6
4x5
4x8
4x8
4x6
4x6
4x6
4x8
4x8
4x8
4x8
fix8 I
fix8
fix8
4x6
4x8
4x8
4x8
4x8
4x30
4x10
Gx8
6x8
Gx8
Gx70
6XIG
16
4x8 4x8
4x8
4x1Q
4x1Q
4A C
4.02
4x12
f5x8
5x8
fix8
6x8
6x10
6x10
6X10
19
48 48
410
410
410
4x12
402
4A4
6x8
6x8
6x8
6x30
6x10
6x10
6x12
20
4X8 4x 10
4x 10
4x 12
4x 12
4x 1+4
4x 1+4
6x8 6x8
& 10
6x1Q
6x1t}
6x12
6x12
6x12
If joists are within 18 Fnches ofgrade, use pressure
' Deflection base on U360 (LL only)
-treated.
Douglas fir•larch
or Fundatinn`5rade redwood.
3 Load Duration Factor = 1
dx+4
4xfi
4x6
4x8
4xi0
fix8
4x10
Gx10
4x14
5x 10
404
602
fix14
Rafters span 13' on 24" centers. The below calls for 2x8 rafters and I'm using hem/fir pressure treated
2x10s. Also, these tables assume the weight of a traditional sheeting/shingle roof and I'm just using
31ga galvanized corrugated steel.
Table B/Milnimum Rafter Sues (Inches)
Rafter I Rafter Spadn.-Ca-91Q, ti_ Ccntc- 0nchi-rl
Wn
(fm)
12
o`PlYrdatl
x311,11 Lh'
Sit132`t4vvod tlfi`VVA.U,.I
sIw 3r.1 iilY,,: _iF 3r.1-iiY.,;
(V`
-11F ar., di Yam;
6
2x+4
2x4
2xd
2xd
7
2x4
2}�xb
2}}x4
2}}x4
p
3
2x6
2x6
2x6
10
2x6
2x6
2x6
11
2x6
2x6
21K6
12
2xi1
2x6
2x6
2x8
13
M
3x5
2x8
14
2x6
2x6
16
2xg
15
2x6
2x8
200 .
16
2x8
2x8
2x8
2x30
17
2x8
2x8
2Xl0
200
18
2x8
2x8
2x16
2x16
19
2x8
2x10
2x14
2x12
20
2x8
2x1U
200
2x12
Deflection base on Lf360 (LL only)
Load Duration Factor= 1.25-
I've also engaged a certified engineer:
DATE:
1/7/2022
COMPANY:
I Perco Engineering, PC
VITRUVIUS BUILD:
Base
DESIGNED BY:
Danny Parrrent
CUSTOMER:
I Rue Deck cover
REVIEWED BY:
Danny Parrrent
PROJ. ADDRESS:
i --
PROJECT NAME:
Rue
98117
LEVEL:
Roof
LOADING:
ASD
MEMBER NAME:
Front Roof BM w/metal
roof CODE:
2018 International Building Code
MEMBER TYPE:
ROOF BEAM
NDS:
2018 NDS
MATERIAL:
Solid Sawn _
Douglas Fir -Larch
No. 1
(2) t5 X 11.25 DRY
INCISED
12'
Page
1
Start (ft): 0 End (ft): 12 Member Slope: 0112 Actual Length (ft): 12
Area
Ix ly
SSW
Lams
G
Kcr
(in')
(in') (in')
(Ibf/ft)
Creep Factor
33.75
355.96 6.33
7.7
2
0.5
1
.�.
_
Fb (psi) Ft (psi) Fv (psi)
Fc (psi)
Fc_L(pQ
E (psi) x10'
Emin (psi) x1o'
Base Values
1000 675 180
1500
625
1700
620
Adjusted Values
800 $40 144
1200
625
IBIS
589
CM
1 1 1
- 1
1
CT
1 1 1
1
1
1
1
Ci
0.8 0.8 0.8
0.8
1
0.95
0.95
CF.
1__ 1 1
1
1
1
1
Bending Adjustment Factors
Cfu = 0.74Cr = 1
Unbraced Length (ft)
Beam End
Span - - _ Length (ft)
Top Bottom
Elev. Diff (ft)
CL(Top)
1 1
0 1
0
1.00
2 10
0 10
0
1.00
3 1
0 1
0
1.00
PASS/FAIL
MAGNITUDE
STRENGTH
Shear Stress Y (psi)
PASS g5.5_ )
177.3
180.0
Bending Stress Y (psi)
PASS (19.0%)
695.0
857.9
Deflection (in)
PASS (80.8%)
0A19 (=L/1250)
0.100 (=L/240)
Bearing Stress (psi)
PASS (16.2%)
579.7
692.0
CL(Bottom) CL(Left) CL(Right)
1.00 1.00 1.00
1-00 1.00 1.00 -
0.86 1.00 1.00
LOCATION (ft) LOAD COMBO DURATION FACTOR C
0.96 D+Lr 1.25
1.08 D+Lr 125
12 Lr
PAR 1.25
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Posts are connected to beams with Simpson Strong -Tie "AC" post caps and rafters are connected
to beams with "H1" hurricane ties.
Regarding blocking in the rafters; IRC R802.8 (Lateral Support) says "Roof framing members
and ceiling joists having a depth -to -thickness ratio exceeding 5 to 1 based on nominal dimensions
shall be provided with lateral support at points of bearing to prevent rotation." I'm using 2x10
rafters with a depth: thickness ration that meets but doesn't exceed 5:1. Am I missing something?
If so, let me know and I'll add blocking.
Note that the existing deck was built as part of a previous permitted remodel in —1974. In addition to
the ledger board it's supported by two 4x10 beams spaced 3' and 12' from the house, on 4x6" posts on
6' centers on poured concrete footers. I believe it originally had a hot tub on it and is clearly more than
capable of safely supporting the added patio roof.
Also note instead of a ledger board I'm supporting the house -side beam using three "SkyLift" posts
from SkyLift Hardware. These attach directly to the wall plate of the house, and have been shortened to
12" for greater lateral stability and less potential uplift. Note that while SkyLift does manufacture a
"pro" version of their hardware it's intended for much heavier construction of conventional
roofing with sheeting and composition roofing.
The enclosed Skylift Technical Evaluation Report shows that both the standard and pro risers
are rated for 2500 lbs of load each. Calculations of the materials weight and a 25 lb/sf snow load
give a combined total weight of —12000 lbs or —2000 lbs per riser, even assuming a level structure
(the pitch of the structure will actually result in a lighter load on the roof risers).
Thank you,
Randy Rue
20208 86th Ave W
Edmonds WA 98026
206 245 0967
randyrue@gmail.com