I’m planning to install 1/2″ random-width reclaimed yellow pine flooring on 3/4 ” T & G osb subfloor. (New construction). The flooring is on the main level with a full basement underneath. I’ve read different articles & seen different builders using roofing paper as a vapor barrier. I’m trying to decide if I need to lay a vapor barrier at all. Any thoughts/sugesstions???
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If the basement is heated you probably don't need a vapor barrier. However, the paper laid under wood flooring, I've been told, was to keep the flooring independant of the subfloor so that it could slide as it expanded and contracted. I never really knew if that made sense but an expert may know.
wreathman,
Using paper under floors has many advantages.
It creates a barrier to moisture migration from below. No, it will not stop moisture migration, but it will slow it's movement.
It provides a "gasket" and helps the floor fit tighter at the tongue and groove.
It allows the flooring boards to slide into place easier during installation and creates a good back drop to visualize joints during racking. Paper also holds and displays chalk lines well. This allows a quick glance every few courses to make sure the runs are staying straight.
I've begun using red rosin paper over the 15# felt to keep the palms of my hands and knee pads from getting black.
Hope this helps.
Ditch
So, you actually use both! I've just been told by a contractor that he uses just the rosin paper. I think that I will use both. Thanks
Bec
Would rosin paper by itself enough to slow down the migration of moisture? I understand all your points except "It provides a "gasket" and helps the floor fit tighter at the tongue and groove." Also the paper is supposed to give you a quieter floor.
Tom
With today's subfloors being glued and screwed 4-by-8 sheetgoods instead of plank decking, as well as the improved moisture controls that are built into today's houses, I think the importance of felt as a vapor or dust barrier has waned a bit. Older construction? It's still a valid topic.
Still...use one or the other for reasons already mentioned, plus, if you're a flooring installer, it's expected by homeowners and the industry groups for warranty and supposed "quality of installation" issues. In other words, if your installation fails, you'd had better installed paper.
I think for the most part that tar paper and red rosin paper can be used insterchangeably under wood strip flooring. The only time I DON'T advocate the use of tar paper is over RFH.
That's what I mean by "gasket". Papers a cushion between the subfloor and finished floor. The tighter the floor fits ( given that it is properly fastened) the quieter it will be.Ditch