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Laminate Flooring Over Carpet?
In my 2-storey home, there's a
"bonus" room atop the attached garage. I want to put in
laminate, but I'm worried about the floor being colder in the winter (the
garage is not heated and I live in Canada!).
I wonder if I could put in the laminate on top of the existing carpet? It
was formerly a medium pile carpet, but has been worn really badly and is
now quite thin. It doesn't feel like there's much underlay left. Do you
think the laminate could go on top of the carpet? If so, would I still
need a foam underlay?
Thanks for your help.
Elizabeth
I
can't say for certain that it wouldn't work, but laying any flooring
material over carpet sounds like a recipe for disaster.
Most flooring materials need a firm, or solid, base. While it is true
that laminate can be installed as a "floating" floor over a
thin layer of approved foam sheet, installing laminate over any else
would almost certainly void whatever warranty the flooring had.
With such man-made materials the only thing to do is follow the
manufacturers instructions or recommendations.
If you want more insulation in the floor, there are many reasonable ways
to obtain that while working from below. The garage below must already
have some sort of drywall for a fire barrier. That barrier must be kept.
You can add foam insulation to the ceiling and then install more drywall
over the foam. Just make sure drywall screws are used that are long
enough to penetrate at least one inch (25 mm) into the floor joists
above.
But... you might just go ahead and rip out the carpet, install the
laminate, and see how things go. My experience is that heat loss through
the floor is often negligible, since warm air tends to rise, the ceiling
insulation in that bonus room is the most important element. You might
consider adding insulation to the walls in the garage, if the walls are
not already covered with drywall. If the garage door leaks a lot of air,
you may be able to replace the weatherstrip on the bottom and reduce the
drafts. Also, make sure any other windows or doors in the garage have
adequate weatherstripping to keep out drafts.
But I believe that insulating the garage ceiling is your best bet. You
would only get an R-value of maybe 2 or 3 from the old carpet anyway.
You can add 3/4 inch (19mm) thick polyisocyanurate foam and get R5.6 or
so. If you place the foam over furring strips to create an air space,
the R-value goes up to around 7.
If an increased thickness in the floor does not interfere with any
doors, it may be possible to try this: Lay down a layer of
1/2" or 3/4" isocyanurate foam on the old floor (carpet
removed), and then apply a layer of plywood or OSB, and then lay the
laminate flooring. But... I would first talk to a technical rep for the
flooring manufacturer as well as the foam insulation maker. Some foams
are strong enough to walk on, IF there is adequate sheet material above
to distribute the load.
Certainly one method that would work is to lay down furring strips (such
as 1x3's) and lay 3/4" foam between the strips. Then apply a proper
layer of plywood/OSB on that. The only question here is: what is the
proper thickness of plywood or OSB. 7/16" OSB can easily span 16
inches when used for roof sheathing, but that will give some springyness.
But... your floor has some serious support between these furring
strips... the foam and the original sub-floor, so the roof comparison
doesn't really hold. 1/2" OSB is better still, and not too
expensive. That way the weight on the foam will be minimal. What I'm
afraid of is this: the foam and the furring strips are slightly
different thicknesses, and the OSB sheathing layer has a little bounce
to it, which you might feel in the finished floor. This is probably a
very unlikely scenario... but I like to be cautious, so I would use the
thickest OSB I could afford, but no more than 3/4".
Ask your local building material suppliers for some specific information
about the crush resistance of isocyanurate foam.
Bruce W. Maki, Editor.
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