attaching Polyisocyanurate

[bapos]

Over the weekend I bought 25 sheets of used Polyisocyanurate 4x8 panels. they are used and don't have any type of foil facing. It has some type of matted thick covering but thought I would ask here if there would be any issues using some type of liquid nails or something similar to that to keep it bonded against the wall? Ive never worked with it before so any help will be appreciated.

My goal is to install the windows then lay down this as a radiant/vapor/sound deadener http://www.hytechsales.com/prod85.html to seal up the walls .... fir out the walls and put the polyiso in there and also maybe some cans of expanding foam in areas I cant get the polyiso in?

Let me know your thoughts


Bapos

[Malkieri]

Something like these (air conditioning duct) clips might be handy and work out better for you. I wouldn't know where to get them locally but they seem like a better way than just straight glue. I did ductwork years ago and we had a welder kinda gun for them. Maybe you could adapt something to do a similar task.

[lornaschinske]

A special liquid nails is made for foam. We used regular LN on the pink faomboard. It stuck but when I pulled on of the pieces off, it had huge voids where the two materials reacted badly. I also used Great Foam as a "glue" to hold the pink foam to metal. The lousy beaded poly panels were pressed into place between the horizontal furring strips. Then I used metal tape to seal seams between furring strips and foam as well as filling any gaps with Great Foam. Our walls are securely attavhed. We will insulate the floor from outside and it will not be a floating floor.

[roach711]

I used the DOW polyiso foam boards with one blue plastic-like side and one foil side (foil side facing the wall or ceiling). I called Liquid Nails and they told me to use one of the polyurethane based adhesives on those panels. Finally used LN for Marble and Granite and it's still holding well one year later. Had to prop my panels against the ceiling and walls with "T" sticks overnight so the adhesive could set up.

I read that the foil faced panels need a small air gap between the foil and the wall so the heat can be reflected back the way it came. I used dollops of adhesive every foot or so and didn't press the panels up tight to the walls so there would be a gap over most of the panel.

[family wagon]

Which kind of foam do you really have? So far the thread has references to extruded polystyrene (XPS), expanded polystyrene (EPS), and polyisocyanurate. Dow's "blue board" aka Styrofoam and Owens Corning's "pink board" aka Foamular are both XPS. Hot cocoa/coffee cups, made of the tiny white beads/balls, are EPS. IMHO these are the two most common. I don't think I've ever seen either of the polystyrenes faced with anything. Polyisocyanurate is another story; I've seen it faced with foil, thin plastic (like plastic wrap for food), and a fiberglass-reinforced paper. Samples I've seen of polyiso have been white-yellow in color; it looks similar to the polyurethane or latex expanding foams "Great Stuff" etc.

The polystyrenes are dissolved by solvents in many glues and so can be tricky to work with. I recently used 3M Super 77 to bond a piece of XPS to the back side of the drywall cover for an attic access hatch in a building. I left it to cure a day or two before getting back to install the cover and it seemed to have bonded well, but I can't say anything about its long-term hold because I haven't been back to open that attic since. I expect the Super 77 would work on polyiso too.

Polyiso is frequently used in commercial flat roof projects, and it's common to use an adhesive to apply EPDM sheeting to the surface -- the same stuff used for "rubber" roofs on many RVs. You might try a local roofing supply place to see what they offer for polyiso.

Keep in mind that polyiso is hygroscopic: it can absorb and even wick up water. You'll want to install it in such a way that it stays dry. Don't forget about condensation that happens when heating in a cold climate, or when cooling in a warm humid climate.. Building Science Enclosures That Work is a favorite resource of mine.

[bapos]

I looked long and hard to make sure I got some polyiso. The boards came from a tore down metal building so they have a matted type finish on the outside of them. Ill see what I can do to get a pic of it so people may have a better look as to see what I can use.

Malkieri............. I am sure AC supply here locally in fort worth will have those clips. I do not mind going that route. I have used those clips before when making duct work when I was doing HVAC work.

I know we have covered a lot of types of glues and what not but Im sure I will find something that will work but Im curious once its all up be it glued tacked and foil taped .... I do plan on putting luan or some other type of wall material to finish it out... Just curious what happens if it comes loose inside the wall? Never really done this cause Im use to working with Batt insulation?

Family Wagon.... very good info you shared. Thank you. I am planning on using this to vapor barrier/sound deaden/ the wall before I insulate it.....http://www.hytechsales.com/prod85.html so I am hoping this product works out cause everyone raves about buskote so Im hoping this follows the same hype.

Thank you all for all you have shared..... much love

Bapos

[roach711]

Just for the halibut I did a test of water wicking of DOW Super Tuff-r polyiso insulation board. I cut a small strip and stood it up in a pan of water for 48 hours. At the end of that time I cut the strip in half and found that the edge of the strip that was in the water was wet but no moisture had migrated up any higher. This (admittedly unscientific) test suggests that the polyiso boards have some resistance to moisture, at least on the short term.

If I get bored tonight I may set up a longer term test for a month or so.

[bapos]

We are expecting rain here in my area (which is RARE this time of the year) so I moved my insulation to a shipping container. Got a better look at the insulation. It is coated with paper. So not sure if I will have issues with material or not but Im leaning to having those pins in the wall and push those large washers to keep it held against that wall.

What do you guys think. Ill try and get a pic of the insulation.

[Malkieri]

Originally Posted by bapos

We are expecting rain here in my area (which is RARE this time of the year)

Rain AND temps in low 80's rare indeed, but we are not complaining here!!!

[family wagon]

Originally Posted by roach711

Just for the halibut I did a test of water wicking of DOW Super Tuff-r polyiso insulation board. I cut a small strip and stood it up in a pan of water for 48 hours. At the end of that time I cut the strip in half and found that the edge of the strip that was in the water was wet but no moisture had migrated up any higher. This (admittedly unscientific) test suggests that the polyiso boards have some resistance to moisture, at least on the short term.

That's good news; I'd love to use polyiso on mine. I'll confess to having been caught relaying advice acquired elsewhere regarding the risk with water. Can't remember now whether it was a particular manufacturer, the polyiso manufacturers association, or somewhere else.

[roach711]

If I had it to do over I'd seal the cut edges and butt joints with the foil tape that was mentioned earlier, or at least fill the gaps with "Great Stuff" foam. Probably overkill but one less thing to obsess about.