Using infill panels in post and beam construction

[dea]

 

8) Hi, I am a newbie. 8)

I have been contemplating building a modular post and beam home.  I have reviewed James Mitchell's book and really like the idea of using an infill panel between a 4'x8' opening between the posts (6"x10").  The infill panel would be comprised of a 4'x8' piece of plywood, foam insullation, and drywall.  For the exterior (on the plywood) I would use Hardie plank.  The panels would be attached to the beams, with part of the beam exposed on the outside of the house and also on the inside.  The reason I like this system is the fact that I am 65 years old and feel I can do this with minimal help, maybe only 1 or 2 more people and no cranes needed.  I have read through other books such as Ted Benson, Steve Chappel, and others, they seem to prefer SIPS on the exterior of the frame and bents, which I don't think I can handle.  I would like to find other books, plans, blueprints and working drawings of what I am looking for or a place to convert a floor plan using this system.  I have also heard this system would promote rotting of the posts because of the difference in outside temp and inside temp.  What is your take on this?  I would appreciate any and all ideas.  Thanks  dea

[Don P]

Hi dea, welcome to the forum.

I've read and seen pics of the problem you ask about. It's caused by an air leak and moisture in the warmer air hitting dew point temperature. If you can detail that tight then its no problem, if you can't, and if you have dew point conditions then there is potential for trouble. If you could accept a total plywood sheathing and a 2x applied over it on the outside copying the post and beam as an accent piece then there is a better opportunity to get it airtight, the outer exposed 2x is easier to replace or repair.

Plywood has maximum span ratings, with 3/4" you'll need a "stud" or purlin of some sort at least every 48". I think 1/2" needs support every 32" on a wall. Check with Hardie on minimum ply thickness and support.