Vapor Barrier On Metal Roof Deck

Both materials make a great physical barrier between the interior building and the metal roof.

Vapor barrier on metal roof deck.

Resistant to foot traffic the engineered composition of v gard provides high resistance to static loading and dynamic impact. Tips for installing metal roofing accessories. Another option for the roofing system is to recognize a hardboard or sheathing layer can be a vapor open air barrier. Metal as the preferred material for self storage facilities.

A gypsum fiber board has a perm rating of approximately 24 to 30 perms depending on thickness and if this board is fastened to a steel deck and the joints and transitions are taped it could be an effective air barrier that allows some drying. Felt underlayment provides little resistance to air and moisture vapor migration and does not serve as an effective air barrier. How to prepare for metal roof installation. For example providing a hypothetical 1 5 open area will.

The most common material used for an insulating metal roof is fiberglass batts or glass mineral wool. Therefore one will often see it installed directly on a roof deck such as a concrete or wood deck or on a continuous substrate such as gypsum board or wood panels that is installed directly over a metal deck. It is therefore suitable for most roofs. V gard provides an excellent vapor barrier with a vapor resistance value expressed by an sd equivalent air layer thickness of 1 500 m.

Selecting metal roofing trim. A vapor retarder is commonly installed on the warm interior side of a roof or wall. Some publications references 3 and 4 note that the amount of diffusion is directly proportional to the open area in the vapor barrier ficks law. Benefits of metal panels for agricultural buildings.

A 15 mil composite reinforced aluminum coated poly with a self adhering sbs. We ll add a vapor barrier so the moist air does not flow up through the insulation and condense on the roof. The batts are located side to side on the rafter of the roof. Architectural metal roofs with felt underlayment are best suited for buildings with proper slope and low moisture loads in dry or arid climates.

The steel deck acts as a vapor barrier preventing diffusion of water vapor out from the bottom of the slab.