Hello All,
     I own a small NY timber frame company. We make our own insulated panels on a very small scale for the projects we do as well as installation. I am looking for advice on what is out there for alternatives to spray foam in panel seam sealing. I am concerned that the spray foam is just not going to hold up over time as well as the possibility of improper sealing due to human error. Do any of you have experience using any gasketing material for this? I already tape interior and exterior seams as well as spec a furred out roof, but feel that the panel seam detailing is lacking.
    Thanks much!

Here are 4 sealing tips:

1. T&G panels
2. EPDM gasket within T&G
3. Peel & Stick tape on underside of panel joints
4. Peel & Stick tape on top of panel joints

Hyland, Your options to seal include mastic, expanding foam (single and two-part), tape, and gaskets.

Your choice should be based on the location of the project. For instance, if all your frames are in New York or an equivalent climate zone 5, you should avoid a non-permeable tape on the exterior. However, a SIP tape applied to the interior would be appropriate along with any of the other options. (There are exceptions to this rule)

Foams that expand to create an air-seal can be a tricky option. The single component foams need moisture to fully expand and have a limit as to how wide a gap they can effectively seal. The two part expanding foams (Froth pack or Fomo) need proper ratio control, mixing, temperature, and storage. Both single and two component work much better when injected into a stable joint. Any movement or application prior to bringing the panels together will cause the foam to collapse and they often will not effectively re-flash to create adequate expansion and sealing.

One of the best options is to use a SIP specific sealant. I avoid the term adhesive as most construction adhesive is not appropriate for air-sealing. Materials like subfloor adhesive or similar turn hard after curing and can not maintain a seal as the structure ages, settles and moves. A proper sealant will remain forever pliable and maintain the seal as things move.

The gasket I use on all jobs is simply sill-seal. Cheap and readily available, sill seal is the ultimate as a SIP installers gasket. You can find some really fancy and expensive gaskets that are marketed to the SIP industry (And high end window installations). They will expand to fill the void. (If you can get it properly in the joint before it expands too much).

The three biggest ways to ensure good air-sealing is to have a good "Panel Layout" and a qualified panel installer followed by a blower door test.

Good job on specifying a back-ventilated roof cladding!

Al Cobb
Director: SIPschool
Training and consulting for the SIP Industry

Hi Lbear,
    I make EPS foam panels, so I have never tried a T&G panel, although I do tape both seams. I am quite interested in the EPDM gasket for this application. Are you aware of any particular sources for these? I have heard that Trelleborg might be a source, so I will give them a call. I'll put a bit of thought toward the application of T&G panel, although it sounds like it might be hard to accurately groove. I wonder if the T&G would be worthwhile if the EPDM gasket is used...

Al,
   I am intrigued with the sill seal option! Like you said, cheap and available. I will still look for some high tech gaskets for particularly sensitive areas ( wall panel to roof panel juncture etc.). I have been using single part foam ( Dow Great Stuff) and have been trying to pre spray with a water mist for curing moisture. I have not messed with mastic.
  You say to avoid a non permeable tape on exterior seams in my climate. I have been using ZIP sheathing as my exterior panel sheathing, with the propriety ZIP tape. I am guessing that the tape is non permeable, although the coating on the sheathing itself is permeable. Thoughts?

I used an EPDM sill seal from "Conservation Technologies" 800 477 7724. I found them through this forum. I am happy with the results.