HomeMy WebLinkAboutLetter; Roof Fastening RequirementsJOSEPH W. SCHULKE, P.E.
JODAH B. BITTLE, P.E.
WILLIAM R STODDARD, Ph.D., P.E.
July 7, 2020
Mr. Douglas Harvey
Building Official
SCHULKE, BITTLE & STODDARD, L.L.C.
CIVIL & STRUCTURAL ENGINEERING • LAND PLANNING • ENVIRONMENTAL PERMITTING
St Lucie County Building Department
2300 Virginia Ave.
Ft Pierce, FL 34982
Re: Smith Residence - Roof Fastening Requirements
6129 Carlton Lane
Port St Lucie, FL 34987
Permit #
Dear Mr. Harvey,
The roof for the single-family residence located at 6129 Carlton Lane, Port St. Lucie, will be
covered in accordance with Florida Building Product Approval #29444.
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), V,,It = 160 mph
Nominal Design Wind Speed (3 second gust), V.a= 124 mph
Exposure Category C
Risk Category II
Enclosed Building
Internal Pressure Coefficient, GCpi +/-0.18
Mean Roof Height, h = 18.00 ft
Roof Slope 3:12 & 6.12
Directionality Factor, Kd = 0.85
Effective Area = less than 10 sf
The resultant component and cladding ultimate design uplift pressures are:
Zone 1 (interior) -53.07 psf
Zone 2 (perimeter) -92.37 psf
Zone 3 (corner)-136.60
IFIVE C;of'*f
1717 INDIAN RIVER BLVD., SUITE 201, VERO BEACH, FLORIDA 32960
TEL 772 / 770-9622 Fax 772 / 770-9496 EMAIL info@sbsengineers.com
Certification of Authorization No: 00008668
1
Page 2 of 2
The resultant component and cladding nominal design uplift pressures are:
Zone 1 (interior) -31.84 psf
Zone 2 (perimeter) -55.42 psf
Zone 3 (corner) -81.96
See sheet S 1.1 of the attached plan set for a depiction of the roof zones.
On the attached product approval, page 1 of 2, Method 2 specifies allowable nominal design
maximum pressures for new wood decks: (maximum design pressure -78.5 psf).
Zone 1 and Zone 2 design pressures are meet as specified and shall be fastened in accordance
with the Florida Product Approval #29444.
The design pressures in Zone 3 exceeds the design limitations of Florida Product Approval
#29444. Increased fastening density in this zone is calculated in accordance with RAS 117.
Zone 3:
FS = -78.5psf x 1 fastener per 18" = 1 fastener per 17.24"
-81.96psf
If you have any,
Sincerely, = -
Date ° /7% 11
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[uestions or require additional information, please feel free to contact me.
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FL Reg W1 60-76051n