Can I use 30# tar felt paper between cement /plywood and cement/carpet padding for a moister barrier

Is this installation below grade? You know they call tar paper roofing felt for a reason.

Tar paper is an old term used when roofing felt (actually it was made of old rags) was saturated with cold-tar pitch which I believe is a residue of the coke making process used in the manufacturing of steel.. Therefore the name "felt" was given to the roll of roofing material. Modern roofing felts are made with either a paper base or a fiberglass base which is then saturated with roofing asphalt.. The name of this roll would be called asphalt-saturated roofing felt (or paper).

Hence, the old name of tar paper has stuck (sic) and most of us in the roofing trade just call it felt, knowing it is really asphalt saturated roofing felt.

The same goes when the term 'tar and gravel' roofing is used. Very few roofs today are made using pitch (tar). Asphalt is used. And should appropriately be called asphalt and gravel, predominately used in a built-up roof system (B.U.R.). This is not referring to the single ply roofing membranes or the 'torch-down' modified bitumen roofing membranes.

Just a bit of explanation from an old roofer/contractor who so far has spent more than 51 years in the roofing industry.

Anthony from Canada