Hi frist time here posting I'm Building a timber frame and putting sip on walls and roof.  What product do you install between T&G and sip on roof will you are doing your panels so weather does not get T&G wet.

You could use a standard house wrap material such as tyveck or typar, it is permeable and will breathe thus allowing the materials to dry if the do get wet. you could use a standard 6 mil poly or even a tarp depending on what you want. You do not need a vapor barrier between the T&G and panels so you can remover whatever you put up.

where are you building that is another thing to consider.

i am building in northeast Maine. It will be a couple of weeks before i get my panels on. So I was looking for a product to keep it dry. This time of year we get alot of mositure.

Great, where are you getting your panels they should be able to provide you with information. also the TF company you are using should be able to get you the information that you need. Who are you using? I am a manufacturer in NH of panels and like to network with other companies. We have a few Projects happening in maine.

Although your post was two weeks ago, if you haven't gotten to this stage yet, here's my suggestion.  Poly isn't the best material to permentantly have installed in that location unless you make it a true vapor barrier.  It needs to be continous, overlapped sealed with tape.  That can a struggle in windy conditions and moisture will likely be present on the outter surface when you do the installation.  Poly covering the roof during panel installation is inconvenient, as well.

I recommend that you keep the exterior side of the wood t&g interior finish covered with large constuction tarps until you are ready for panel installation.  Install panels during dry conditions to avoid trapping any latent moisture in the roof system.  The objective is to have a dry surface to work with. 


You will be sealing the interior seams of the SIP essentially from the "inside out".  Use a bituminum based, synthetic, self-sealing tape (refered to as SIP Sealing Tape in some SIP manufacturer's literature.  Tape comes in various widths with 9" and 12" wide being convenient.  Layout and caulk where all veritical (eave to ridge) and horizontal (gable rake to gable rake) panel seams will occur.  You will unroll the product and adhere the exposed adhesive side of of the tape to the top surface of the t&g just prior to installing panels. 

During roof panel installation, as you are about to set the panel into place, and when the manufacturer's panel-to-panel connecting and sealing procedure as been completed, peel the backing off the exterior face of the SIP tape, lay the panel in place as close to its final position as posible.  Install the panel, adjust fit (you will have this abilty even with exposed tape adhesive; just be diligent in your approach).  Finally, fasten the SIP panels to the timber frame, per the project's fastening schedule and recover the installation with your large construction tarps.  (You may have panel-to-panel foam sealing to do after the panels are fastened and befor you cover the outter surface.  This depends on the SIP manufacturer's procedures.) 

If you have time during that work session to install the next layer, that would be 30 lb felt install in the customer fashion.

You will end up with state of the art moisture sealing at the seams between panels (a vapor barrier) and a felt underlayment over the outter layer of OSB (a vapor retarder).

Peghead in CO