Some materials in the roof assembly may require venting of the steel roof deck, such as roof systems with light weight insulating concrete. Venting does not impact the structural performance of the steel deck. Deck should not be specified as vented when it is not required. The drawback of venting deck is when concrete is poured, the slurry drips through the vent tabs creating debris on the surface below. Cleaning up the slurry or protecting the surfaces underneath with plastic sheets adds cost to the project without providing any added value to the owner when venting is not required. The requirement for venting the deck should be clearly indicated in the specifications and be clearly stated in the deck schedule on the structural drawings.
For B, N, 2W, and 3W deck, upward protruding vent tabs are factory punched in the low flutes of the steel deck when venting is specified, as shown below.
For CP-32 venting is achieved by adding embossments to the side lap holding the lap open, as shown below.