Rigid Insulation Roof Over Decking

Rigid foam insulation installation prepare roof deck.

Rigid insulation roof over decking.

Materials appropriate for insulating sheathing with unvented cladding substrate include. Nail it around the edges with roofing nails. Specify this solution zip 8 39 mb. It is an acceptable practice to install a new roof over an existing roof membrane system provided that the roof deck is structurally sound and has been properly prepared to support the added load.

Polyisocyanurate extruded polystyrene xps. After the roof deck is prepared the rigid foam boards need to be cut to size to fit snugly together on. The insulation installed over the roof deck must be installed in multiple layers with joints offset in order to control convective looping at joints between insulation panels. Most unvented attics incorporate spray polyurethane foam spf on the underside of the roof deck and attic walls.

Suited for a wide range of applications foamular extruded polystyrene xps insulation is ideal for roofi ng applications including single ply protected roof membrane assemblies prma tapered vegetative roofs plaza decks architectural metal roofi ng and recover roofi ng. Start at the bottom of the roof and place the first piece of rigid foam insulation against the metal flashing starting at the center line. Get all the construction documentation you ll need in a single click. Steel deck with fully adhered single ply membrane over a cover board with xps insulation over gypsum board thermal barrier or applied directly to the metal roof deck.

This construction approach was first used in the 1970s and it has been implemented much more widely since it was first included in the international code council s icc model building code in 2007 irc section 806 4. The rigid insulation over roof would have controlled the temperature of the condensing surface the underside of the roof deck so that i would not have had to use the spray foam except at the perimeter to provide the air seal to the tops of the walls.