Construction of exterior walls for torsional stiffness.

[calvin82]

Need some input on different solutions. We're building a small summer cottage that will be left cold during winters. We'll be building without a vapor barrier and using cellulose insulation.

Alt. 1 (from outside)
Cladding
Batten 34mm
External gypsum board
120mm insulation
internal battens 45mm + insulation

alt. 2
Cladding
Batten 34mm
Wind barrier
120mm insulation
battens 45mm + insulation
OSB

alt. 3
same as 2 but without OSB internal instead stiffening with perforated tape.

All interior surfaces will be some form of tongue and groove paneling.

Grateful for any feedback.
(It’s important to me that it’s fairly easy to build and uses as little expensive sheet material as possible.)

 

[petterovski]

If you want to avoid expensive board materials as you write, then skip OSB internally. You're going to have tongue-and-groove paneling inside anyway, it seems unnecessary with OSB/Plyfa which is usually placed behind gypsum to have something better to hang things on.

Metal strapping or just diagonal bracing with wood in a few sections on each wall?

 

[calvin82]

Thought about making recessed braces in the corners. But it is a bit of a hassle, though.

 

[Gabbe1]

You can indeed brace at an angle with the internal 45x45 without it becoming too much extra work.

 

[petterovski]

You can just put a single 12mm Plyfa board on each wall to stiffen them up. About 900mm closest to the corner. Then cut down the 45 rule just where the board sits to 32 mm.

3 out of 4 walls should be sufficient.

 

[calvin82]

You can just put a single 12mm Plyfa board on each wall to stiffen it up. Like 900mm closest to the corner. Then cut down the 45 rule just where the board is to 32 mm.

3 out of 4 walls should be enough.

smart! Thanks

 

[calvin82]

You can just put a 12mm Plyfa panel on each wall to stiffen it up. About 900mm closest to the corner. Then trim down the 45 rule just where the panel sits to 32 mm.

3 out of 4 walls should be sufficient.

One issue is that the wall height is 3000mm, so I can't fit a full panel in height, but maybe it's enough to cross-brace so that a 2500 panel can be attached at all edges?

 

[petterovski]

Maybe it's good to take a 1200 board so you get it over 3 wall studs. Add another piece at 500mm above and splice together with a strip that you place behind and screw into.