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Structural Engineering, Design & Testing, CA#28948, NOA#13-0222.02
6915 Washington Rd,West Palm Beach, FL 33405/Phone(561)804-9908/Fax(561)804-9907/e-mail:turginc@aol.com
July 30, 2015
TO: St. Lucie County / Building Department
FROM: Riza N. ALTAN, P.E.
SUBJECT: Flat Roof Uplift Pressures & Base Sheet Enhanced F..r
ADDRESS: Residence for Deutsche Bank Trust;Co.
2994 Conifer Dr., Ft Pierce, FL 34982
CONTRACTOR: Larry Neese Roofing, LLC
Dear Sir:
The re-roofing specifications for flat roof areas of the subject residence are rev
ie3ED
myself. The purpose of this letter is to determine the wind uplift pressures and ene
spacing of the mechanical fasteners.
The one-story-high property is located in Exposure C area. The flat roof areas consist of and
5/8" plywood deck with positive drainage. The roof mean height is 10 ft. As per the 2014
Florida Building Code, ASCE 7-10, 165 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:
Field: P1 = -44 psf . / Perimeter (4'wide): P2 = - 74 psf / Corner (4'x4'): P3 = -111 psf
The proposed CertainTeed Modified Bitumen Roof System over Wood Decks (NOA #14-0224.03)
consists of mechanically attached Empire-All Weather Base base sheet, followed by
torched-down FlintLastic GTA modified bitumen cap sheet.
The system max. design pressure of -60 psf (Deck 1I, Syst.E(3), page 14116, Limitation #7) is
specified by tin-tagging the base sheet with 11 ga., 1'/4" long ring-shanked roofing nails,
spaced at 811o.c. along the laps and 811o.c., three rows staggered in mid-sheet.
It is required that, as per RAS 117 in order to meet the actual roof pressures, the base sheet
is tin-tagged to the existing wood decks in the following enhanced pattern:
Zone 1: Field (Intermediate areas): @ 8"o.c., staggered three rows in mid-sheet
Zone 2: Perimeter (4' from edges): @ 6"o.c., staggered three rows in mid-sheet
Zone 3: Corner (4' from ea. side): @ 4"o.c., staggered three rows in mid-sheet
Laps: Field (4"min.): @ 8"o.c., Perimeter @ 611o.c. & Corners: @ 411o.c.
Therefore, this letter is to certify that installation of CertainTeed Modified torched-down -_
Bitumen Roof System (NOA #14-0224.03) conforms to the requirements ,of-the -2014_ Florida
Building Code which specifies 165 MPH ultimate wind speed for Risk Category II ly,fARMure
C area. ���E N. At, ®�0,
i, \ •1es2•e pD .
If you have any questions regarding this matter or I may be of further-assS`tan�r�',,& e°°do ��
not hesitate to call me.
y
_+ N,.38521`
Sincerely,
L a _ STRTE-OF" ==
_+
Riza N. ALTAN, P. 38521s/0NA . s �
Consulting Engineer gc �g4