Polystyrene for ceiling in shop??
Hello, all. Back again from the Knots with a question for my shop. I’ve got a 45′ X 36′
woodshop (pole barn), and the ceiling trusses were installed the traditionally cheap way, 9′ on center, with purlins (or gurts, I forget which is which) to support roof 2′ on center perpendicular across. Before insulating with R-30 bats, I installed 2 x 4’s across the underside of the interior ceiling to create a grid to nail a finished ceiling to. Drywall is completely out of the question, because the weight will sag the ceiling.
I’ve decided on white polystyrene, 3/4″ or 1″ thick. I don’t need the extra R value, as the shop stays quite toasty in winter. I just want to retain it better, and am tired of looking at the brown paper. I figure that the white poly will give a decent reflective quality for light.
My big question is, can the poly sheets (4’x8′) be just glued up, or do I need a fastener (washer nail)? Or, what do you recommend? Having those orange, or pink washers showing all over the ceiling isn’t exactly attractive, even though it isn’t my #1 concern. All help is appreciated.
Also, what adhesive do you recommend?
Jeff
Replies
I know that "PL" make an adhesive for gluing poly to block foundations. Would probably work on wood also. Will need the nail washers maybe temporarily till the glue sets. use a nipper to cut the head off the nail, sine you can't pry against the styrene.
Are you sure you want to use styrene? Sounds like the R-factor is not a concern. With ply prices dropping I would consider a luan board. It's lightweight and can be painted and installed with a finish stapler or brad.
Not sure but I thought the white polystyrene was a fire hazard... Needed to be Rocked over. Something about toxic smoke if it burned.
Yep, PS is a fire hazard. Burns much more readily than wood. Don't leave it exposed- it will not only generate bad smoke if it burns, it will also be a significant fuel to the fire if one should happen.
If all you're looking for is a light coloured material to reflect some light, why not a layer of Tyvek? Doesn't burn nearly as readily for one thing.
IIRC ... cyanide based off gassing too when it burns...
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Nope: you're confusing polystyrene with polyurethane (i.e. Corbond etc.). No nitrogen in polystyrene, so cyanide in the smoke is pretty much impossible. Polyurethane smoke will contain a fair bit of cyanide from pyrolysis of the isocyanate groups. Polystyrene burns to produce a styrene-laden smoke which would be pretty bad for you too, but not on the order of cyanide. But you won't care much about the smoke when the flaming, melting PS is dripping down on you from above!
serious fire hazard waiting to become a serious problem with the styrene...
glue and washer heads to hold it if you do install it...
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming
WOW!!! What a Ride!
Forget the primal scream, just ROAR!!!
Try what I did....ribbed white pole barn steel panels. They span the 8' - 9' truss spacing just fine, no worries about flammability, already white. Screw 'em on the flats with self-tapping 1" screws with white heads.
Also, why the worry about weight of sheetrock, on a finished portion of my shop I also fastened 2X4s on 24" centers between the trusses, using joist hangers. Supports 5/8" X-rated sheetrock AND 30" of blown in FG just fine.
Edited 9/11/2006 1:13 pm ET by johnnyd
Problem with the weight is the 2x4's were just nailed up flat, not vertically, into the bottoms of the trusses. I had to re-screw them, as they were sagging. I know they won't take the weight of drywall now, and I'm not redoing it all. NO WAY, NO HOW!
Jeff
Ditto the fire concerns above. The Tyvek idea sounds good. Put it on backwards so you don't have to read the printing whenever you look up.
Yeah, I wouldn't use any sort of foam unless it's explicitly fire-retardant in nature. Tyvek should be good, though, as others have stated. It will not support combustion.
Thanks to all for the help
I hadn't even thought about the fire hazard of polystyrene. Thanks for bringing it up. Tyvek isn't what I had in mind, as I don't want to hear it waving away in the breeze when I have the doors open in the warmer weather. I'm looking for a rigid surface that will lighten the ceiling, as well as keep the heat from escaping in between the bats of insulation. I'll think on it some more.
Metal panels are what I constructed the exterior of, and it is now so dang expensive, that I was looking for an alternative, but there may not be one.
Jeff
Those cheap white panels they use in some restrooms would probably do the trick.
If Tyranny and Oppression come to this land, it will be in the guise of fighting a foreign enemy. --James Madison
I agree on the Tyvek flapping in the wind. That would drive me nuts. I can understand some folks worrying about the fire hazards of foamboard... but I tend to lean towards the "so what" side of it. Many pole barns already have foamboard on the walls, so who cares if there is foamboard on the ceiling?!
You're talking about your own personal shop/shed, not some sprawling industrial complex. If a fire starts and somehow gets away from you, you walk out the big door or little door. Not like you're going to get trapped in a maze of passageways while the foam burns and offgasses.
I haven't tried to put foamboard up in that fashion, but don't see why you couldn't. Some of the farmers hereabouts will staple chicken wire under the rafters so that they can put fiberglass batts up there. Seems like you could wire the foam to that if you think it is going to sag between the rafters.
And if you get really carried away, you could even seal the seams between sheets of foamboard.
jt8
"Success is not the key to happiness. Happiness is the key to success." --Albert Schweitzer
Hang a grid from wires and go with drop tile?
Spheramid Enterprises Architectural Woodworks
" If ya plan to face tomorrow, do it soon"
That's probably not a bad idea. You can put the grid on a slant, if you want to retain the "vaulted ceiling" for whatever reason.
If Tyranny and Oppression come to this land, it will be in the guise of fighting a foreign enemy. --James Madison
I'v only hung a few over the yrs. But the are lightweight and easy as can be to do. Include lights, speakers, vents..the sky is the limit.
Spheramid Enterprises Architectural Woodworks
" If ya plan to face tomorrow, do it soon"
Yeah, and you don't have to go all the way to the walls. Can make it even tiles both ways, to just get close to the walls (as close as you want), and leave it basically just hanging, with no attachment but the wires.
If Tyranny and Oppression come to this land, it will be in the guise of fighting a foreign enemy. --James Madison
Well, there are a few things to consider....
If your rafters are on 16" or 14" centers, I'd use the steel wires that are used to hold fiberglass insulation up. They simply wedge in place, between the rafters.
Styrofoam is a bit fussy to cut and trim; the foil-covered stuff is much easier to work with.
There is also no reason you can't paint that brown paper.
Gluing Styrofoam can be a bit touchy. This is mainly because many glues attack / destroy it. Test a sample first.
Another problem is that a rigid foam board will not actually touch the ceiling in that many places. You just might have the stuff come loose in a month or two. I'd consider using those adhesive-backed soft foam strips. Attach them to the panel, then glue them in place.
" There is also no reason you can't paint that brown paper."If you are talking aboutthe vapor barrier facing on FG bats, it has the same problem as foamboard.It is not suppose to be installed without a cover. Look at the printing." Gluing Styrofoam can be a bit touchy."Not trickly at all. Just need to read the label on the adhesive. It will tell you Yes or No.
O.K., as I understand this, your trusses are 9' apart.That means your 2x4's for your ceiling are spanned 9' and there on the flat.Thats way to far to hold up much of anything but..... what if you went to mid span of the 2x4's and ran a wire up to the girt/ purlins.Now you have cut the span in half.
On my shop ceiling, I insulated with FG an put that cheap 32ga galv. corrugated metal ran parallel to and on the bottom of the ceiling joist. I strapped mine with 1x4's first. Mine were on 16'' centers but I think those 2x4's with the wires would hold fine.
I done this purely for economics but I think it looked pretty good when I got done. A bonus to this is (don't know how high your ceiling is ?) when you inadvertly(sp)smack it while flipping a long piece of wood -and you will :)- there is no damage.
It's worth checking the price on that cheap metal, not the same stuff you would put on the outside of your building. Also, besides looking cool, it reflects the light really well.
Did I mention it's cheap!
dug
OK dug, I dig it ! ; ) Now where do I get me some? Sounds perfect for my own shop. And I know what you're talking about- as big as my shop is, I've already had to patch the VB where I knicked it while flipping a board. Drywall wouldn't fare much better, and there'd be more cursing involved after knicking it!
I hate to mention is now, but you could have gotten R-30 bats with white PSK facing, instead of kraft paper. The stuff is low flame spread, and is designed for commercial applications where it will be left exposed.
http://www.wbdg.org/productguide/pdfs/oc_flm_sprd_submittal.pdf#search=%22PSK%20insulation%20facing%22
You could get some rolls of the facing material now and just staple it in place. I have a buddy who'se unfinished basement ceiling is covered this way.
What about corrugated fiberglass panels ?
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