I need to replace my roof. Is there any type of decking that will help with energy cost and I would also like to know if it is a good idea to put that poly coating on the decking before you put on the new singles.

txhagirl

You did not indicate the construction of the house and the type of roof.

The house was built in 1911, currently there are 3 layers of roofing one is composite and the other wood singles. I have on idea about the bottom layer. Because of the age of the house and all the layers I am thinking it would be a good idea to replace the decking.

txhagirl

The house was built in 1911, single story and not a big pitch to the roof. Currently there is 3 layers of roofing one is composite and the other singles. I have on idea about the bottom layer. Because of the age of the house and all the layers I am thinking it would be a good idea to replace the decking also. But then I am new to this old house remodeling thing.

txhagirl

In general roof decking is replaced as needed. Of course if a large percent is bad then all of it can be replaced.

But in many case most of it will be good.

The decking might be skip sheating, which was original used on wood shingle roofs. In that case they might put a plywood layer OVER the decking. It is thinner as it is not the main support.

You would not normally add insulation to the exteriro of the roof. But it is done in some case where the ceiling is in direct contact with the roof structure (cathedral ceilings).