Insulated concrete forms (ICFs) are attactive for a number of reasons, but present problems with timber frames. The biggest problem is the lack of structural support at the outer and inner edges where the foam is. The concrete core may only be 4 inches wide in an 8 inch block. Using a 10 inch block will help. One of the problems we have encountered most often is the walls must be well braced before pouring or they will bow and then dry that way, never to be moved again. The thickness of the various components setting on or attached to the ICF's must be taken into account. For example, a 4 inch brick ledge will let you apply a masonary skirt up to a 5 1/8" urethane wall panel, and the floor system can be extended close to the outer edge of the concrete core, which will put your timber posts over the strong core of the ICF's. LVL blocking can then be used to transfer the weight of the frame through the floor system, or you could set a timber sill and post up from there.
I think an ICF wall with timber trusses and SIPS on the roof would be a great home - practical, warm and bulletproof.
Polysteel and BluMax are the two I have experience with, and there are some new companies coming out with new systems at every show I go to. Hope this helps. Good luck.
Brian O'Shea
Originally posted by Rich Littauer:
I am designing our first Timberframe home and am considering using foam foundation forms instead of traditional foundation forms. I do not want to have to insulate the timberframe deck over a finished basement and so our code requires insulation of basement walls. The foam foundation panals do this. Can you recommend using these forms and would you have a manufacturer recommendation. Thank you.
