I am planning on building a family room in the basement of our new home. As
basements go this one is likely to be quite dry. The basement is only half
deep in the surrounding grade and the land is a mixture of sand and rock.
During heavy rains this land drains very quickly. Following advice from
this NG I shall use pressure treated 2"x4"s for walls against the basement
walls and for sole plates. I want to insulate between the studs set against
the basement walls.
What kind of fiber glass should I use for insulation? Is aluminum foil
backed fiber glass still available?
Also should I attempt to seal the floor against damp before installing
carpeting? If so, what should I use? Paint, plastic membrane, other, etc?
I did not use pressure treated wood to stud up against a basement wall and
never had any trouble, also used fiber glass insulation between the studs.
Regarding the cement floor--moisture will come up through the floor and go
through any carpeting with no ill effect. Be careful how you try to seal
it. I would not use any plastic membrane because vapor will get trapped
under the plastic and you'll end up with water there. I had carpeting on the
cement floor with a good pad and never had a moisture problem.
Not to change gears on you but why are you using pt for wall studs? Do you
want chemically treated wood in your house? Have you given thought to steel
studs. I used them in some framing I did and they are a real treat. They
have their own issues but for framing, they're great. You could also use
regular lumber with a membrane below for the sill.
As to your flooring question, I believe there is an underpadding that has a
moisture barrier built into it. The best way is to raise the floor (if you
have room) by laying 2x4's flat and covering with plywood. You can also
insulate between the studs to make the floor more comfortable.
You may also consider a new product that looks kind of like egg carton made
of pvc. It allows water and air to flow around the product and keeps it
away from the flooring. You can buy rolls of the stuff and cover it with
plywood or you can buy ready made (plywood with this stuff glued to the
bottom) 2' x 2' squares that fit together. The only thing with the ready
made jobs is that you have to build your walls on top of them if you are
going to put carpet down (otherwise they won't stay down when you stretch
Not necessary to use PT for the studs. They should be half an inch or
so from the concrete walls. Not necessary to use PT for the sole
plate. In northern climates, general practice is to install a
moisture barrier behind the studs and under the bottom plate,
beginning at ground level or four feet whichever is the lesser..
Standard fibreglass insulation is fine. Then a vapour barrier floor
General practice here is to carpet directly onto the concrete.
Usually an eight to ten pound pad and a 32 oz or higher berber.
Your local codes may require treated wood for the bottom plate, touching
concrete. Do not set the studs directly against the wall--the wall may
not be plumb or square, and concrete always transmits some moisture from
the earth that can wick into the wood. Set the stud wall an inch or so
from the exterior concrete wall, and make sure the stud wall is
independently plumb and square.
You also don't want the insulation directly against the concrete for the
same reasons of moisture wicking. If you use kraft paper backed
insulation, you'll staple its edges to the front of the studs.
Don't overlook the possibility of steel studs. They do have some
differences and disadvantages, but also some powerful advantages. After
all is said and done, I believe they are superior to wood for basement
"To announce that there must be no criticism of the President,
or that we are to stand by the President, right or wrong,
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.