SpecTips - Reducing Insulation Fasteners in Mechanically Fastened Single-Ply Roofing Systems

Using Carlisle SecurShield® Polyiso to Reduce Insulation Plates and Fasteners

Insulation fastening requirements are typically less stringent in mechanically fastened single-ply roofing systems compared to those of adhered single-ply roof systems.

In a typical adhered single-ply roof system, insulation securement is critical for uplift performance. This is because the roof membrane is adhered only to the insulation, relying solely on its securement to the roof deck for uplift performance. Typically, adhered single-ply roof systems utilize mechanically fastened insulation. Therefore, in order to increase the uplift performance of an adhered roofing system, additional fasteners are needed to secure the insulation to the roof deck.

In a mechanically fastened single-ply system, insulation plates and fasteners are much less important for the overall uplift performance. This is because the membrane itself is secured to the roof deck using plates and fasteners installed in the seams of the membrane. The seam fasteners are installed through the insulation into the roof deck, anchoring not only the roof membrane but also the insulation. To improve the uplift performance of a mechanically fastened single-ply roof system, additional fasteners and/or heavier- gauge fasteners are required in the seams.

Insulation plates and fasteners in mechanically fastened single-ply systems are necessary to ensure that the insulation boards stay in place during installation and remain abutted on all edges to maximize thermal performance. However, their use adds cost and complexity to the installation and reduces the thermal performance of the insulation through thermal bridging.

Carlisle’s SecurShield products help to alleviate these issues because they allow contractors to use fewer insulation plates and fasteners in mechanically fastened single-ply roof systems.

Carlisle’s SecurShield products feature coated-glass (CGF) facers on both sides of the polyiso core and provide superior performance over that of glass-reinforced felt (GRF) faced insulation products. SecurShield products provide exceptional resistance to moisture, as well as increased fire performance and wind uplift resistance.

Carlisle’s newly published detail, MF-27E, addresses the newly reduced fastening requirements when utilizing SecurShield polyiso insulation in mechanically fastened single-ply roofing systems. The new detail requires only four insulation plates and fasteners per 4’ x 8’ board regardless of warranty length or wind speed.

SPEC TIP In 3-Part Specifications – Part 2 “Products”, include the following criteria:
  • The roof shall have a top layer of polyiso insulation that conforms to ASTM C1289 Type II, Class 2 or 4.
  • The insulation shall have Coated Glass Facers on both sides of the board.
  • The insulation shall require a maximum of 4 insulation plates and fasteners per 4’x8’ board.
View the SecurShield Polyiso Product Data Sheet here.

View Carlisle Detail MF-27E here.

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