2.5.4 Flooring Joists and concrete subfloors | Owners Corporation Network

2.5.4 Flooring Joists and concrete subfloors

There is no easy way to accurately determine the projected IIC rating or a floor covering until it is installed and tested in the field. A large reason for this is the different types of subfloors – concrete or wood joist, which can have a large effect on the IIC rating of the floor covering. In addition, other sound deadening materials (an underlayment for example) can add to the IIC rating. To give you a better idea of the difference these factors make, the tables below show estimates of the excepted IIC ratings that you may achieve with the type of floor system shown. The first table shows floor coverings tested over concrete subfloors and the second table shows floor coverings rated over a basic floor joist system.

Approximate IIC ratings for a 150–mm–thick concrete slab with various kinds of toppings.



IIC Rating

None, or ceramic or marble tile


Vinyl flooring


Hardwood flooring


9–mm–thick hardwood on 5–mm–thick resilient layer


16–mm plywood or OSB on 40– x 90–mm wood strapping on 25–mm mineral fibra board


35–mm concrete on 25–mm mineral fibra board


Carpet and underlay