Replies

1. GBA Editor
   Martin Holladay | Mar 01, 2011 02:54pm | #1

   John,
   The short answer is, "The best tape to use is the tape recommended by the SIP manufacturer." R-Control sells their own tape for this purpose: R-Control SIP Tape.

   Similarly, the best "goo" for sealing the panel seams and splines is the "goo" recommended by the SIP manufacturer -- in this case, a product called "Do-All-Ply."

   A quote from the R-Control SIP Construction Manual:
   "R-Control Do-All-Ply is a sealant which is safe for expanded polystyrene foam insulation. Apply the Do-All-Ply in a continuous 3/8” bead as shown in the R-Control SIP details. This size bead will result in the optimum coating when the plates and splines are installed."

2. 
   bdrfab | Mar 01, 2011 06:32pm | #2

   Our local SIP supplier (Porter Corp) is actually using expanding foam for the sealant on joints. Do-all-Ply was way less of a PITA IMHO. Martin is dead right on the tape. So it's 3x the price, instead of $100 you spend $300? To me its cheap insurance.

3. 
   albertrooks | Mar 01, 2011 08:40pm | #3

   Siga Rissan 60 is a great choice for this application also. Not to be a broken record, but similar issues apply. Long lasting, Vapor closed for the interior layer and no VOC's. Forms extremely well to OSB, modest price point ($27 for 82").

   I really don't believe that spray foam in SIP joints is a long lasting air barrier beyond moderate effectiveness both initially and over time. Adding (anybody's) tape on top of the foam joint does bring it up to a extremely tight and long lasting air barrier in my opinion.

   That said, I also suggest that it's important to make sure that your well within you SIP Vendors warranty. The interior panel joint is a potential vapor intrusion point. If there ever was an issue and damage occurred, I'd want to be sure that the project was well within warranty compliance.

4. 
   Faulted1 | Mar 01, 2011 10:06pm | #4

   Aaron,

   The supplier said "it was not worth it." I disagree. Therefore, I would like to apply tape and the best possible. Is that wrong?

5. 
   bdrfab | Mar 01, 2011 10:25pm | #5

   Nope. You're supplier is wrong. I'd tape it, for the exact reasons as Albert mentioned. It's a sad truth that even if you do things by the book, litigation gets really expensive fast if there's a problem. So err on the side of caution, If R-control has has a tape, use it, or get written permission to use another brand. Same thing with the foam sealant. I didn't care for it, but it's their warranty, and I have no desire to void it. Just my .02

6. 
   Faulted1 | Mar 02, 2011 06:53pm | #6

   R-Control requires the following:
   "SIP Tape: Provide SIP Tape at joints between SIP roof panels and at intersection of SIP roof and wall."

   I'm not using Sip roof panels.

   Therefore, the supplier's tape is not for wall joints. Would anyone recommend the best tape to use for the wall joints?