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Structural Engineering, Design & Testing, CA#28948, NOA#13-0222.02
6915 Washington Rd,W Palm Beach, FL 33405/Ph. (561)804-9908/Fax(561)804-9907/e-mail:turginc@aol.com
February 09, 2017
TO: Port St Lucie County/ Building Department
FROM: Riza N. ALTAN, P.E.
SUBJECT: Wind Uplift & Flat Roof Covering Specifications
ADDRESS: MAJEWSKI Residence/246 NE Mainsail St., Port St Lucie, FL 34983
CONTRACTOR: One Way Roofing, LLC P'Y
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Dear Sir: '�
The re-roofing specifications for the rear flat area of the subject residence are reviewed by
myself. The purpose of this letter is to specify the wind uplift pressures and enhanced
j spacing of mechanical fasteners for the attachment of base sheet.
The one-story-high —24'x12' flat roof is located in wind Exposure C area. The mean roof
height of the building is 15 ft. The existing 6/8" CDX plywood deck requires to be re-nailed
ito measure 6" o.c. in field and 4" o.c. in corner/perimeter zones.
Asper 2014 Florida Bldg. Code, ASCE 7-10, 160 MPH ultimate wind velocity, for Risk
Category II in Exposure C area, using Wind Load Factor of 0.6 for ASD, the wind pressures
are determined as follows:
i
Field: Pi = -44 psf / Perimeter (4' wide): P2 = -74 psf / Corner (4'x4'): P3 = -111 psf
The proposed Tarco Self-Adhering Modified Bitumen Roofing Systems over Wood
Decks (NOA #12-0703.06) consists of mechanically attached Leak Barrier Easy Lay base
sheet over existing plywood deck followed by all self-adhered Leak Barrier Easy Base ply
sheet and mineral-surfaced EasyStick Plus cap sheet.
The max. design pressure of -60 psf (Deck 1, System E(1), page 8/10), is achieved by
tin-tagging the base sheet, spaced at 7" o.c along the 4" laps and 7" o.c. staggered three
rows in mid-sheet.
It is required that, in order to meet the actual roof pressures, the base sheet must be
attached to the existing plywood deck in the following enhanced pattern:
Zone 1: Field (Intermediate areas): @ 7"o.c., staggered in three rows, in mid-sheet
Zone 2: Perimeter (4' from edges): @ 4" o.c., staggered in three rows, in mid-sheet
Zone 3: Corners (4' from ea. side): @ 4" o.c., staggered in four rows, in mid-sheet
Laps: Min. 4" wide, Field: @ 7" o.c., Perimeter: @ 4" o.c., & Corners: @ 4" o.c.
Therefore, this letter is to certify that installation of Tarco Self-Adhering Modified Bitumen
Roofing Systems over Wood Decks (NOA #12-0703.06) conforms to the requirements of
2014 Florida Building Code which specifies 160 MPH ultimate wind speed for Risk Category
II in Exposure C area
If you have any questions regardln this matter qi�l t ay�be-060�er assistance,_ .lease do_ ._-
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