We have a design for a principal rafter-and purlin timber frame. We are thinking about using 1x6 T&G finish under a single or double chip panel roof, but are not sure what the structural implications would be, or if the 1x6's could be pre-applied to the sip. If we were to use a 1/2" drywall as our finish in other areas, could that be applied to the panels prior to installation? And if so, would we need spacers over the timbers? Lots of ?'s, I know!!! Any information would be greatly appreciated.

Also, I forgot to mention, we are forming gable dormers with the roof sips.

What I've usually done is install the T&G directly to the frame, before installing the panels. It's much easier to nail it to the frame from the back side, as you don't have to blind nail it through the tongue of each board. I also highly recommend either buying pre-finished T&G, or applying the varnish to the paneling yourself before you install it.

With the drywall, I've done it two different ways:

One is similar to what I described for the T&G: attach it directly to the frame (using screws through the back side of the drywall) before you install the panels. This means that there are only a few screws holding it up until you get the panels on. Once the panels are up, screw the drywall securely to the panels from the inside.

The other method is to install spacers to the outside of the frame, and then install the panels. The spacers create a gap between the frame and the panels, so that you can slip the drywall in between. Although it takes a little longer, it's less likely to rain if you do it this way .

I have never tried attaching the drywall to the panels before installing them. I think it would be very easy to damage the drywall while the panels are being installed.

Good Luck with your project! CB.

At a recent log and timber frame home show a timber frame company rep was giving a talk about panels and installation.
He said the panel industry is moving away from installing sheet rock and or paneling on the panels first then installing the insulated panel to the frame for the damage factor. Also, once the panel with sheet rock is attached to the frame it needs to be waterproof to prevent rain from damaging the sheet rock.
Which ever method you choose from the before mentioned procedures, be sure to be ready to protect your entire roof from rain until it's shingled and weather tight.
Good luck with your project.
Jim Rogers

Thanks to both of you for your replies. In our neck of the woods, it only rains if we are trying to put up hay. Therefore, since haying time is awfully busy for us, and would be too busy to panel the house, ergo we shouldn't get rained on. (That is, unless I wash a window or my car.) Thanks again and we'll take your advice.

Patty