I put the PL-300 in several small circles on the back and then pressed it against the wall. If done correctly, the small circles will act like a suction cup holding the piece against the wall. Seemed to work well about 90% of the time for me. I had some issues in the corners because the concrete walls were a little rounded so I would have to lean something against it to hold it.
Good to know. I did the small wall last night and it has been braced for almost 24 hours so we'll see. Will that PL-300 work for sealing where the boards meet, the joints i guess? Just don't trust that Tyvek tape 100% to stay up there flush for years to come. Thanks.
The PL will not seal the gap between the sheets. I used the house wrap tape. I had some issue keeping it in place after some time. I think the issue was dirt on the rigid foam. If you wipe down the seams to remove any loose dirt I think the house wrap tape would work just fine. I'm pretty sure that is what Mike Holmes uses so it can't be wrong right?
I assume you are talking about the seam between pieces? I wouldn't say I am 100% sure but after working with the stuff I just don't see how it would work. I just feel like the stuff would dry out and crack ruining any seal that you would have had. You might be able to get it to work along the floor but I don't think it will act like caulking if that is what you are looking for. Since you will have the PL-300 you might give it a shot with a couple of pieces and see what it does. Would only cost you a day to see if you think it will work the way you want it to or not.
I used the Tyvek tape but noticed that the tape didn't stick perfectly - very likely due to some dirt on the XPS panels as noted above. I ended up applying a tiny bead of Great Stuff into the groove just before putting the pieces together. Then cover with the Tyvek tape. Problem solved. (Disclaimer: that's pretty clearly overkill, but I'm a "suspenders and a belt" kind of guy.)
For an inside 90 you can fold the tape in the middle and stuff it in the corner as you work your way up or down the wall. Then run another strip down each side to help hold it. For an outside 90 I ran a piece from top to bottom overhanging the corner and then folded it over to the other piece making sure I pulled everything together nice and tight. Then threw in a piece on each side to help hold it again.
This is about the best pic I could find of my install. Unfortunately I don't have a closer pic.
Wow thanks a lot for that pic. That looks really good, hopefully I can do as good of a job as that. I wish I could afford the space to put xps on the floor but I simply cannot as I am 6'4". I think I'm going to pass on that Great Stuff and just tape the seams really well and use the PL-300 on the floor as it is a very minimal gap. For the floor, since I'm doing a submarine build was going to use those rubber mat squares that look like coins http://www.greatmats.com/interlocking-floor-mats.php. Trying to decide if i should place them under the bottom stud plate or not and take them to the xps wall.
I have a few more in my build thread but this one is about the best that I could find. I was worried about losing height as well (between the 3/4" foam and 5/8" plywood) but with 9' ceilings it really didn't become an issue. I have a couple of bulkheads that are lower but still probably about 8'.
I'm not sure about the tiles. If it were me I would probably just frame my walls with a pressure treated bottom plate and then fill the floor in with the tiles in the middle. That way if you ever decided to change the floor you wouldn't have to cut around the walls to free the perimeter tiles. Just my $0.02.