Flex TPO Mechnically Attached Systems Perimeter - Manual

8/2012 1
Flex Membrane International Corp. 2670 Leiscz’s Bridge Road, Suite 400, Leesport, PA 19533 Tel: 610-916-9500 Fax: 610-916-9501
FLEX TPO PLUS
MECHANICALLY ATTACHED ROOF SYSTEMS
PERIMETER SHEET REQUIREMENTS AND FASTENER GUIDE
Perimeter Sheets:
Flex TPO mechanically attached roof systems require the installation of ½ (half) sheets along the roof
perimeter. The roof perimeter is defined as the edges of each roof section. Situations that involve multi-
level roof areas that meet at a common wall, the adjacent edge of the upper roof is treated as a roof
perimeter if the height difference is greater than 3 (three) feet. A perimeter sheet is not required at the
base of the wall.
The height of the building and the wind uplift pressure requirements of the project are factored to
determine the number of perimeter sheets to install. A minimum of one perimeter sheet is required.
Sloped roof assemblies equal to or greater than a 2:12 slope require a minimum of one perimeter sheet to
be installed centered over the roof ridge.
Buildings that have canopies or overhangs or large openings in the walls require the additional installation
of perimeter sheets in these areas. Contact Flex Technical Services for assistance in determining the
number of perimeter sheets to install in these roof areas.
The following chart is provided to act as a general guide to assist in calculating the perimeter sheets
required for most installations. The project specifications, Building Code requirements or Factory Mutual
approval may dictate fastener/plate placement options and the installation of additional rows of perimeter
sheets with enhanced membrane securement.
Wind Velocity Building Height Number of Perimeter Sheets Required
≤ 100 mph ≤ 50’
50’ to 75’
1 or 2 *
2
100 to 129 mph
≤ 75’
2 **
≥ 130 mph ≤ 75’
4
Notes:
1. Fastener assembly spacing for perimeter sheets is the same as required for the fastener
spacing of the roof field area sheets.
* Installation of 12’ wide membrane requires 2 rows of perimeter sheets fastened 12” o.c.
** Gypsum or Cementitious Wood Fiber Decks in the 100 to 129 mph wind zone require
installing 3 rows of perimeter sheets.
The following chart is provided to act as a general guide to assist in determining the fastener density
required for most installations. The project specifications, Building Code requirements or Factory Mutual
approval may dictate fastener/plate placement options other than those listed below.