My client would like to use an infill system for part of his Timber-Frame.

Has anyone used Icynene or other spray foam for an infill system?

Any suggestions, comments or details welcomed.
-Collin

I used icyenne in a stick built situation about 6 yrs ago...it is expensive but it does do a great job of insulating (i think the r value is 7 per inch). I was thinking of using it again in the exact way that you are..would be very interested in what you decide(or how you decide) to use it..

One of the most common arguments against infill systems is the concern over air leakage at gaps/beam interfaces and thermal transmission through framing members. Not much you can do about the main frame unless you are willing to install a layer of foam sheet on the outside (or hide the timber frame). As for the other issues, consider an uncoupled wall structure (such as used in sound abatement). You end up building 2 2x4 stud walls, one for the outside and one for the inside. Provided you leave at least an inch gap between the two your foam should fill the void and break the thermal conductivity. A nagging thought says your savings would be minimal so I would question the economics but that is perhaps better left to someone who had the time to do the research. The other thought re: the infill/timber interface is to borrow an idea that I saw up at Canterbury Shaker village. Install a small spline in the post/frame so that you maintain an air block as the frame shrinks or things shift. What I saw at the Shaker village was that they rabbetted thier siding boards and used small splines to fill the gaps. Very practical as you did not have to worry about edging a board or damaging the tongue and pretty effective at restricting air movement.

Andy

Andy,
I appreciate your comments and information regarding the splined siding at the Shaker village.

We are going to give it a try. I am going to adapt a couple of ideas I saw in the new Timber Frame Joinery and Design book put out by the Guild. The title is The Infill System for the Lancey House.

They are using panels whereas I will will use spray in place Icynene. This enables me to adapt it to braces,etc. The "spline" in this case is urethane foam sprayed into a groove that is on the timber and the 2x4 attached to it.

I will let you know how it turns out at least in the short run for labor, cost, etc.
-Collin

Collin
I would appreciate if you could keep me informed as to how this works out for you, as what youre attempting is something i would like to use on a future project..