Lightweight Concrete Roof Deck

The most common use of vermiculite lightweight concrete is for light structural roof decks and for insulation fill over metal decking and structural concrete.

Lightweight concrete roof deck.

Lightweight insulating concrete low density non structural concrete comprised using ultra lightweight expanded mineral aggregates or preformed foam. With structural lightweight concrete a mix of shale slate slag and clay are used and with this mix the aggregate is fully saturated prior to mixing. Vermiculite for roof decks can be placed over various kinds of form boards fiber fiberglass acoustical and asbestos cement. When structural lightweight concrete is then poured the aggregate voids are loaded with water.

If a roof is installed over the top surface and the deck was cast into non vented metal form deck the logical conclusion is that the dry down mechanism is at best severely retarded. The end result of the structural lightweight mix is a deck that can be 20 25 lighter than standard structural concrete. Serd is a specialty subcontractor providing lightweight insulating concrete roof decks metal decking tectum acoustical roof deck panels engineered fills and material sales. With standard structural concrete the aggregate used is sand and stone.

However when a lightweight structural concrete lwsc roof deck is poured in place it uses significantly more water. The normal weight concrete employs standard aggregates i e. Beneath the roof cover structural concrete roof decks are commonly topside insulated using adhered insulation panels or cast in place lightweight insulating concrete. Lightweight insulating concrete lwic is defined as having oven dry unit weights of 50 lbs ft or less.

Compressive strengths from 125 350 psi are common for lwic used in roof deck. Structural concrete deck a cast in place concrete deck serves as an integral part of the structure and is designed to carry heavy loads normal weight concrete is typically used for cast in place construction.