HomeMy WebLinkAboutROOF FASTENING REQUIREMENTS JOSEPH W. SCHULKE, P.E. JODAH B. BITTLE, P.E. WILLIAM P. STODDARD, Ph.D., P.E.
S CHULKE , B ITTLE & S TODDARD, L.L.C.
CIVIL & STRUCTURAL ENGINEERING · LAND PLANNING · ENVIRONMENTAL PERMITTING
1717 INDIAN RIVER BLVD., SUITE 201 VERO BEACH, FLORIDA 32960
TEL 772 / 770-9622 FAX 772 / 770-9496 EMAIIL info@sbsengineers.com
May 27, 2021
Mr. Douglas Harvey
Building Supervisor / Building official
St. Lucie County
2300 Virginia Avenue
Ft. Pierce, FL 34982
Re: Flat Roof Fastening Requirements
4235 N. Highway A1A,
Hutchinson Island, FL 34949
Permit #
Dear Mr. Harvey:
The roof areas for the building located at 4235 N. Highway A1A, will be covered in accordance
with Florida Building Product Approval FL1654-R27.
Component and cladding design wind pressures for the corner, perimeter, and interior zones for
the roof section were calculated per ASCE 7-10 “Minimum Design Loads for Buildings and
Other Structures” using the following criteria:
Ultimate Design Wind Speed (3 second gust), Vult = 161 mph
Nominal Design Wind Speed (3 second gust), Vasd = 125 mph
Exposure Category D
Risk Category II
Enclosed Building
Internal Pressure Coefficient, GCpi +/-0.18
Mean Roof Height, h =10.0 ft
Roof Slope 0:12
Directionality Factor, Kd = 0.85
Effective Area = less than 10 sf
The resultant component and cladding ultimate design uplift pressures are:
Zone 1 -109.3 psf
Zone 1’ -62.7 psf
Zone 2 -144.2 psf
Zone 3 -196.5 psf
DocuSign Envelope ID: 13C328B5-8F5E-4975-A46F-50AF79353674
Page 2 of 3
The resultant component and cladding nominal design uplift pressures are:
Zone 1 -65.6 psf
Zone 1’ -37.6 psf
Zone 2 -86.5 psf
Zone 3 -117.9 psf
Attached is a sketch showing the locations of Zones 1, 1’, 2 & 3 of the roof.
On the attached product approval appendix 1, page 17 of 94 specifies allowable nominal design
maximum pressures for new or re-roof wood decks using: system W-60 w/ Tapered ISO (H
Shield) insulation and SBS-SA base ply. (maximum design pressure -67.5 psf).
Zone 1 & 1’ design pressures meet as specified and shall be fastened in accordance with the
Florida Product Approval FL1654-R27.
The design pressures in Zone 2 exceeds the design limitations of Florida Product Approval
FL1654-R27. Increased fastening density in this zone was calculated in accordance with RAS
117. The following are the requirements for the base sheet fastening to satisfy the component
and cladding design pressures for this specific job:
1 fastener = 1 fastener
1.3 sf X sf
67.5 psf 86.5 psf
1 fastener = 1 fastener
1.3 sf(67.5 psf) X sf(86.5 psf)
1 fastener = 1 fastener
87.75 lbs X sf(86.5 psf)
X =1.01 sf
Zone 2 = 1 fastener per 1.01 sf
DocuSign Envelope ID: 13C328B5-8F5E-4975-A46F-50AF79353674
Page 3 of 3
The design pressures in Zone 3 exceeds the design limitations of Florida Product Approval
FL1654-R27. Increased fastening density in this zone was calculated in accordance with RAS
117. The following are the requirements for the base sheet fastening to satisfy the component
and cladding design pressures for this specific job:
1 fastener = 1 fastener
1.3 sf X sf
67.5 psf 117.9 psf
1 fastener = 1 fastener
1.3 sf(67.5 psf) X sf(117.9 psf)
1 fastener = 1 fastener
87.75 lbs X sf(117.9 psf)
X =0.74 sf
Zone 3 = 1 fastener per 0.74 sf
If you have any questions or require additional information, please feel free to contact me.
Sincerely,
Date:
William P. Stoddard, Ph.D., P.E.
FL. Reg. No. 57605
cc: HannaBri Services, Inc.
DocuSign Envelope ID: 13C328B5-8F5E-4975-A46F-50AF79353674
5/27/2021