I am renovating a room with a concrete ceiling. Previous ceiling (wood paneling)
had been removed. The concrete ceiling is a bit uneven and requires smoothing
which I'd rather not do.
I am thinking of paneling the ceiling with styrofoam sheet about two inches
thick. I 've got some good quality styrofoam (smooth - not grainy) I coul just
My question is about the lights. I haven't yet selected any lights but other
rooms have recessed halogens lights eyebulb style.
Halogens tend to get hot and styrofoam could melt . How much room should I cut
for the 50w lights? (a ball park estimate)
I'm just guessing, but I BELIEVE styrofoam would create some very
interesting fumes in a fire. You'd better research this carefully. If I were
you, I'd check the building code in your town, and maybe speak to someone at
a real building supply dealer. Not Home Depot, not Lowe's. A real supplier.
Foam offgasses for maybe years, it must be sealed and its hard to do.
You also must seal it perfectly tight with no air allowed behind it or
condensation and mold will occure, it happened to me. 2" of red or
blue is only R 11. Foilfaced polyisocyanurate is R 14.4. Foam also
does not allow moisture through, working with foams takes planning and
knowledge. Do it wrong and you can create many problems down the
I get your point and understand that there must be some space left between the
sheets and the recessed lights. That should still lead to warmth buildup. I must
need a hollow space between ceiling and the styrofoam.
Like I said I am asking for advice.
Mind if I ask how old you are? I'm wondering how you couldn't know that
styrofoam produces toxic fumes when it burns.
I'll ask you one more time: When you consulted your local building code,
what did you find out?
Actually, not it doesn't. Other foam may, but Styrofoam is styrene plastic
and when it burns, produces soot (a lot of it), water, carbon dioxide)
About the same as burning fuel oil. Properly covered, it is useful for
insulation and even for Insulating Concrete Forms www.integraspec.com as an
In any case, it should be covered with drywall. This is a poor application
being suggested by the OP.
While polystyrene is indeed somewhat less toxic than some other
types of foams, how toxic it actually is is highly variable depending
on conditions. Eg: low O2 will result in incomplete burn.
The initial combustion products are styrene and carbon monoxide. Neither
of which are good for you.
Age and Treachery will Triumph over Youth and Skill
Not a good idea. Styrofoam is a very good insulation, it is made of a flame
retarding material, but, according to building code it must be covered with
something like drywall. It is not allowed to be exposed. Personally, I'd
not use recessed lighting in foam as the light will get very hot, the
insulation will trap the heat and probably melt.
This is a warm ceiling bottom floor (two floor house). I am thinking of covering
it with a few layers of paint and perhaps some ceiling wallpaper.
The lights is what is a problem. Maybe I should cut enough space or add a an
empty space between the stryrofoam sheet and the concrete ceiling.
I've seen many types of stryfoam mouldings and sheets sold in stores so what is
the big deal of not being able to leave it exposed or just painted.
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