What Adhesive for use with Rigid Foam??

I am about 90% done with Drylok on the exterior walls in my space. I picked up a bunch of rigid foam today from HD. But I was reading the tube of adhesive and have a question:

The adhesive I am planning to use is PL-300, which is specifically for affixing rigid foam to substrate/concrete.

The tube of PL-300 says it is not recommended for attaching rigid foam to sealed concrete. However, the website doesn't say anything like that. Does anyone have any thoughts on this? Is there an alternative adhesive?
http://www.loctiteproducts.com/p/pl_...d-Adhesive.htm

Thanks for any input you have!

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Hi bzbase - thanks for the info. Unfortunately, I need to keep a small airspace between the foam and the theater wall frame in order to preserve my sound-proofing efforts. Ted White told me that contact between the foam and wall framing will couple the two.

So - still on the hunt for the right product. I'm going through the Owens Corning website, but can't seem to find any info on the right adhesive. Maybe PL-300 will be okay...

Thanks for the link sirmebes - that document is interesting and has good info. I've been looking at something similar to that, here: http://www.buildingscience.com/docum...lation-systems.

I'm a little nervous about it because I have two non-porous surfaces that I'm trying to bond, but I bought some PL-300 today and am going to go for it tomorrow. I think I'll wait a few days before spraying Great Stuff around the perimeter in order to give the adhesive as much time to set/dry as possible.

Thanks barlav - I bought some Great Stuff yesterday to use with the 2" XPS in the rim joists but I didn't know if it would be sticky enough to bond the full sheets of XPS to the substrate - based on your experience, it looks like it will work fine...thanks!

Haha- fotto, you're entirely correct. The only higher goal I have here is satisfying my complete anal-ness and extreme paranoia of basement moisture!

My initial concern over the PL-300 was that I read somewhere on the interwebs (which I can no longer find) that using it between two non-porous surfaces meant that it would never dry. I remember reading it, and it was more of the 'comment on a blog' type than an authoritative source. The PL-300 tube also says "not recommended for use with sealed concrete", but the website doesn't say anything about that, so I have decided not to worry about it. http://www.loctiteproducts.com/p/pl_...d-Adhesive.htm. I think I'll just go with a little PL-300 plus some Great Stuff.

And you're also right that there won't be much in the way of force pulling the boards away from the wall - I dry fit one wall last night and it basically stood up on its own - so I could probably get away with just Scotch Tape if I wanted to . I'm going to try to keep the theater framing and insulation from contacting the rigid foam in order to prevent any coupling (again, probably overly anal), but I'm sure PL-300 and Great Stuff will be more than adequate to keep the foam against the wall.

I'm going to use Tyvek tape to seal the joints between the foam boards. Next question (LOL): do I also need a little sealant/caulk for the tongue and groove joint between the boards, or is the tape enough?

Haha - glad you are having a good laugh Andreas! But shouldn't you be off building your theater?? Don't you have a baby on the way or something?? I am hoping that a little extra attention in this phase will prevent me from a potential issue somewhere down the line... But if I were you, I'd be laughing at me too haha!

Thanks Ant - I think that's my plan exactly. And is this also a license to blame you if I run into any trouble???

And thanks for the compliment Andreas!

Hi Guys - Thanks for the input. I must admit, I think this is the most interest I have ever generated in a thread on AVS - very exciting! Having said that, you're scaring me Drew! The horror stories of basement water here are what prompted me to get into all of this Drylok, moisture, foam etc. stuff.

My house was built in 2001 (I am the second owner - purchased in April of this year) and, although I don't want to jinx anything, I have had no moisture since taking possession (other than when I had the A/C replaced and the technician forgot to hook up the line to the condensate pump and it ran for 2 days before I noticed - NOT funny - soaked the half of my basement that is already finished, but that's another story).

So anyway, I had a few tiny hairline cracks in the forms that I patched with Drylok FastPlug, then put Drylok over the whole thing, just for good measure. I haven't seen anything that would indicate that I actually needed to do this, but again, I'm admittedly anal . I cut and dry fit most of the insulation last night and then actually applied about 1/3 of it.

My method was to use four evenly spaced horizontal lines of PL-300 across each piece of foam. Then when starting the next piece, I repeated with the glue and added a small bead of Great Stuff to the tongue and groove joint to try to get a good airtight seal between boards. I then taped the seams with Tyvek tape for good measure. This solution worked very well, although it was definitely overkill on the glue (but I wanted to be sure I didn't end up with big air gaps).

To anyone who may come across this thread in the future - I am clearly a spaz and this method is overkill given my particular situation, but to me, a few extra hours and dollars now has the potential to prevent disaster later, so is 110% worth it IMHO.

Thanks again to everyone for your input - here's a pic of my progress so far...

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That gray fireproof cabinet is just there to be sure the boards don't pull away from the wall at all. It was a house-warming present from the previous owners (more like it weighs about a gozillion lbs. and you need a crane to get it up the stairs, so they just left it).

Hi Tedd - glad to hear the PL-300 works so well! I agree that it's definitely the right thing for applying rigid foam to concrete. The only thing I was scared of at the beginning (and the impetus for this thread) was that in a caveat after the directions, the tube says "not recommended for use with sealed concrete". This concerned me because I put Drylok on the basement walls and I'm pretty sure that is considered "sealed". However, the PL-300 webpage doesn't say anything like that, and when I applied the glue last night, it appeared to work very well. However, I didn't go back down there this morning...maybe all the foam boards are laying on the ground haha! I doubt it - the PL-300 appeared to be the right solution, and gives peace of mind because it won't eat the rigid foam over time.

Holy crap Floyd you got me!! I read your message on my BlackBerry and I missed the bottom line of your note - all I read was the "warning!!" I almost had to run out of my meeting and puke in the bathroom! Thank you for that heart attack LOL!!!!

Don't worry, retaliation will be swift and fierce!

Haha yes that's definitely a good idea Andreas. I had been thinking about other options too. Maybe diagonally, or in a figure 8 shape? Kidding of course. But yes, you make a good point, and I think I will apply glue vertically from here on out.