Solutions to Enable Screw-down Roofs to Expand & Contract

On many Metal-over-Metal retrofit roofing projects, it may suit your budget better to install a new screw-down/direct fastened metal roof in lieu of a standing seam. However, it is important to understand that the use of a screw-down roof is limited by thermal expansion and contraction as well geometry. For existing roofs that are simple gable or mono-slope designs without hips and valleys and with less than 80’-0” panel runs (ridge to eave), use of our standard factory notched Huggers is appropriate. However, for those through fastened roofs with longer panel runs, the new roof will have a significant amount of expansion and contraction and a standard Hugger system may tolerate that amount of movement. Now, you have the option of using our Roof Floater© sub-purlin system.

Roof Floater utilizes a unique thermally active base clip that provides up to 3 inches of movement in the sub-purlin framing system, not the metal roof. Therefore, the entire roof and its sub-framing will expand and contract. Also ideal for other roof materials that are inherent to excessive thermal movement including such as aluminum, reinforced fiberglass panels (FRP) and foam insulation core panels. For new construction wood truss framed buildings that require thermal movement characteristics, Roof Floater’s base clip was designed to be installed directly on the top chord of the trusses. In properly sloped bar joist framing applications Roof Floater will allow the use of through fastened panels in lieu of conventional roofing materials.

The Roof Floater system is available in four different height base clips to allow for thicker insulation to be installed between the existing and new roofs. The continuous 16-gauge hat purlin is manufactured with a height of 1-5/8”.