Minor assembly required...

[MushCreek]

This is a follow-up to my thread about using foam panels. I got an even better deal. I bought 60 2-1/4" thick 4X8 panels for $12 each! Now I just have to figure out how to get them on my ceiling. These panels are specifically for roofing, so they have some sort of a fiberglass-reinforced paper on both sides. I tested a piece of the paper, and although it does burn, if you take the source of the flame away, it goes out. I'm going to put two layers up, attached to the underside of my ceiling joists. That will capture a well-sealed 10" airspace above them, so the insulation value should be pretty good. The panels themselves are rated R-12.5, so a double layer equals R-25. Should be fine for a workshop.

My thought now is to simply paint them with intumescent (fireproof) paint, and call it good. It's expensive, but you can buy an additive for regular latex that's pretty cheap. You just mix it in and apply your paint. My original plan was to buy some used roofing tin, and apply that over the foam, which I suspect would be better, but it's more money and work. The whole building is wood anyway, so by the time the flames reach the 12' ceiling, it would be a total loss.

Now I have to figure out the best/easiest way to attach the panels to the ceiling. Because of the paper scrim, I can use any glue without worrying about it attacking the foam. I figure a quick-grab construction adhesive would work well, but I'll do some testing before I put up the whole ceiling. I'm hoping the glue will permanently hold the panels in place. Holding them there while the glue grabs may be tricky. Years ago, I made an attachment for my engine hoist for putting drywall up. Jack it into place, then put in the screws while the hoist held it in place. In this case, I figured I could apply the glue, jack the panel into place, and just leave it there for 10 minutes? 15? After that, the foam should stay put.

Thoughts? Anyone have experience with these types of panels? I do need to wear gloves, because handling them makes you itch. I better wear a mask when cutting them as well.

 

[geneg]

This is a follow-up to my thread about using foam panels. I got an even better deal. I bought 60 2-1/4" thick 4X8 panels for $12 each! Now I just have to figure out how to get them on my ceiling. These panels are specifically for roofing, so they have some sort of a fiberglass-reinforced paper on both sides. I tested a piece of the paper, and although it does burn, if you take the source of the flame away, it goes out. I'm going to put two layers up, attached to the underside of my ceiling joists. That will capture a well-sealed 10" airspace above them, so the insulation value should be pretty good. The panels themselves are rated R-12.5, so a double layer equals R-25. Should be fine for a workshop.

My thought now is to simply paint them with intumescent (fireproof) paint, and call it good. It's expensive, but you can buy an additive for regular latex that's pretty cheap. You just mix it in and apply your paint. My original plan was to buy some used roofing tin, and apply that over the foam, which I suspect would be better, but it's more money and work. The whole building is wood anyway, so by the time the flames reach the 12' ceiling, it would be a total loss.

Now I have to figure out the best/easiest way to attach the panels to the ceiling. Because of the paper scrim, I can use any glue without worrying about it attacking the foam. I figure a quick-grab construction adhesive would work well, but I'll do some testing before I put up the whole ceiling. I'm hoping the glue will permanently hold the panels in place. Holding them there while the glue grabs may be tricky. Years ago, I made an attachment for my engine hoist for putting drywall up. Jack it into place, then put in the screws while the hoist held it in place. In this case, I figured I could apply the glue, jack the panel into place, and just leave it there for 10 minutes? 15? After that, the foam should stay put.

Thoughts? Anyone have experience with these types of panels? I do need to wear gloves, because handling them makes you itch. I better wear a mask when cutting them as well.

Go find a single ply or membrane roofing contractor. They use long screws with large washers to attach sheet insul to roof decks.
I wouldn't trust adhesive to hold them up permately. Buy a foam gun & use minimum expanding foam at joints or gaps. Could also tape the joints. Handling the insul board shouldn't bother your skin.

 

[hobie18]

Eye doctor today. I thought that last pic was an rv.

What does the framework look like that you will be attaching these?
Any moisture issues?

 

[PWC Repair]

I usually see it attached with these--->https://www.amazon.com/Inch-Plastic...nsulation/dp/B0CHKVHGPZ/?tag=atomicindus08-20

 

[MushCreek]

The problem with the nails is they aren't long enough for a double layer. I'm going through 4-1/2" of foam. The ceiling is 2X10's on 12" centers, so plenty to fasten to. One trick will be keeping the screw aligned well enough so that it hits the joist. I've thought of marking them on the top side and drilling a clearance hole for the screw. That way, the screw will come out in the right place. I've also thought of gluing the foam together, then putting up the full thickness all at once. I could always put up cheap 1x4 strapping first, giving me a much wider target to screw to. More work and more money, though. At any rate, it shouldn't take many screws to hold the foam up there. The scrim on both sides makes it stiffer than bare foam, so less chance of sagging.

 

[Model A Fan]

Just Red Green it. Duct tape!

But on a different note, that is a screaming deal. That thickness at Home Depot/Lowe's is beaucoup bucks. I'd recommend doing a long screw with a fender washer, but that's just what came to my mind. Could you do cheap sheathing material first and then screw these to the sheathing material?

How many square feet will you be covering? Another option would be to glue the foam together in a double sheet then drill holes in it on a grid pattern based on your rafter layout and then lift them into place and screw them in.

 

[jack stand]

Go find a single ply or membrane roofing contractor. They use long screws with large washers to attach sheet insul to roof decks.
I wouldn't trust adhesive to hold them up permately. Buy a foam gun & use minimum expanding foam at joints or gaps. Could also tape the joints. Handling the insul board shouldn't bother your skin.

This^^
I just took a picture of a box of these and for some reason (say something about not having an extension??)
I can't post them. The name is "Gentight"..... insulation screw with plate.

 

[PWC Repair]

The problem with the nails is they aren't long enough for a double layer. I'm going through 4-1/2" of foam.

OK, so grab some 6" turf nails and some plastic cap washers, and you're set!

 

[NUTTSGT]

3" Drywall screws with plastic washers for the first layer.

Second layer needs at least a 5" or preferably a 6" screw with plastic washers.

 

[JSHOUSE1]

Stuff is awesome. When I was tool control officer at a 1600 bed prison in tn, we did a roof job. Stuff coming off was 15ish years old and still looked new in 95% of the areas, i didn't have anywhere to store it at the time.... think it was combo of 4in and 6in. Maybe check your local flat roof contractors.

 

[geneg]

Stuff is awesome. When I was tool control officer at a 1600 bed prison in tn, we did a roof job. Stuff coming off was 15ish years old and still looked new in 95% of the areas, i didn't have anywhere to store it at the time.... think it was combo of 4in and 6in. Maybe check your local flat roof contractors.

The roofers will have screws at least up to 12" long. On some projects they use multiple layers of tapered insulation to create slope. EPDM rubber or synthetic can then be fully adhered to the insul board without a risk of uplift.

 

[wantacoe]

That is the same stuff I used in my 45x50 poles building. There is a place near me that has auctions of building materials once a month. It took me a couple years to get enough but my average cost was about 5.00 per sheet. Some of it had some damage but most of it was good.

 

[WildBill]

We did something like this at a friends place with regular 3" foam board and we put up the first layer with screws/washers and a stripe of adhesive down the joists, it was pretty easy to hit the joists and we used a chalk line when it was helpful. Then we used something like liquid nails to glue on the second layer running the opposite direction. The adhesive was enough that it pretty much held immediately. I can't remember the brand, some sort of thick construction adhesive. I was really glad I had a battery powered caulking gun, we used about 25 tubes. We had some long screws and washers that we put in the first couple pieces but it worked without them so we stopped. I kinda expected them to fall down overnight but they didn't budge.

 

[CraigStu]

Be sure to experiment w/ construction adhesives. For instance I used Loctite PL375 Heavy Duty for one project. It is off white and about smooth peanut butter consistency. Worked great for gluing osb to studs as the screws could pull the 2 together. Another project I used the PL3 Premium. This stuff is more like mayonaise. So thin that a thick bead will run down a vertical surface. The premium was great for sticking some 1/8" paneling to an osb wall. It grabbed quickly but more importantly I feel that it spread out better as I smacked the panel w/ my hand.

 

[MushCreek]

I found some 6" long drywall screws. Coupled with thin washers, they would certainly do the job. My concern with just adhesive is longevity. I don't know how well that paper/fiberglass scrim is attached. Regardless of whichever way I go, I'll probably throw a few screws into it just in case.

Anyone have any thoughts of painting it with fireproof paint? If I pre-painted the panels and skipped the metal roofing, it would save me some money and a lot of labor. I don't really care about appearance other than it be white. The existing scrim is medium gray.

 

[NUTTSGT]

You also have the option to continue with the metal ribbed panels if you were planning on using them.

Put your metal up, cut the foam into strips (table saw) and put between the bottom chord of the trusses.

If you have any left, run a course perpendicular to the trusses.

 

[MushCreek]

The ceiling joists are covered by decking on top. There's a loft up there. No access to the top of them.

 

[KenC]

The ceiling joists are covered by decking on top. There's a loft up there. No access to the top of them.

I think he just wrote it in the wrong order, rip the foam, put between the joists from the bottom then metal.

Or maybe I interpreted it wrong.

 

[MushCreek]

Part of the reason for going with foam is to simplify the process. With the joists on 12" centers, that's a lot of ripping pieces. It would be better to use fiberglass batts for that. Putting up 32 square feet at a time will be a lot faster.