Gypsum Concrete Roof Deck
Provides excellent fire performance non combustible in accordance with astm e136 and it s fire.
Gypsum concrete roof deck. These include office complexes schools public buildings shopping malls and warehouses located throughout the united states. Old bald asphalt roof over wet fiberboard over asphalt felts and the white is a gypsum deck. Gypsum concrete roof deck systems consist of a form board wire reinforcement and a poured application of gypsum concrete. Unlike traditional roofing systems where multiple layers are required concrete roof deck is both the noncombustible structural sheathing and either the nail base or thermal barrier.
Gypsum concrete roof deck systems have been installed since the early 1950 s in all types of commercial markets. Installed up to 48 on center over cold formed steel framing 1 4 bar joists or wood framing to create 1and 2 hour fire rated roof ceiling assemblies. The top of the metal banded material will look like white sheet rock. These fibrous decks generally have a gypsum like or cementitious binder and combine the functions of a roof deck thermal insulation and finished ceiling.
Easy application for concrete floor patch repair on many different types of roof decks like gypsum roof decks. This system provides fire resistance seismic and wind load diaphragm values in addition to an economical roofing membrane substrate. Typcally the poured gypsum deck is about 2 to 3 thick not 1 2 as you previously mentioned and is supported by bulb tees. Gypsum deck from underneath.
Gypsum concrete roof deck system. The poured gypsum roof deck consists of steel bulb tees a form board usually composed of gypsum or fiberglass wire reinforcing mesh and the gypsum concrete. Mill formulated and composed of specially calcined gypsum and wood chips or shavings. Many of these installations continue to perform and provide support to roofing materials that have been added over time.
According to fields corp the compressive strength of the gypsum is 500 psi. Introduced as a roof deck substrate in the 1940 s. If the deck is sound it may be possible to treat the deck much like concrete by priming the surface adhering thermal insulation and installing a new roof membrane. I have generally seen the tees spaced about 30 to 36 on center.
The only cementitious structural panel approved by factory mutual fm fm approval standard 4472. Venting lwic installed over structural concrete and other non venting substrates. Picture story of gypsum roof deck repair sequence nrdca 600 guideline for application of cementitious wood fiber roof deck systems technical bulletin 1001. Gypsum or lightweight concrete deck.
Formboards placed between the bulb tees contain the fast setting poured gypsum roof deck. The bulb tees which are very strong vertically but quite flexible horizontally provide the long span strength.