Timber frame - cross section advice please?

[bendeneo]

Hi all,

I am building a timber frame summer house/garden room/bar, and wanted some advice on the make up of the walls please.

So far I have made the shell out of a combination of 2x4 and 2x3, and have put a warm roof on.... so what I am left with is a skeleton structure.

My thoughts on the composition of the walls were this:

- 12mm OSB for the outer skin of the walls (or perhaps lapping of some sort.... any advice?),
- breathable membrane
- cellotex or similar between the timber
- plasterboard

Should I be considering a different make-up? or any modifications that people can think of to this?

Regards,

 

[Harbourwoodwork]

moisture barrier on warm side of insulation

 

[bendeneo]

Oh yes, of course, thanks! I've got plenty left over from the warm deck.

Do you think OSB on the outside is overkill if I am going to clad it somehow anyway?

 

[Harbourwoodwork]

No its just the job it braces the entire structure outside weather boarding doesn't do that fix it on with coated ring rails

 

[bendeneo]

Thanks for that, much appreciated.

Another question but this time regarding insulation.

I was going to use cellotex, but have seen some cheap 170mm rockwool.

As the majority of the structure is in 3x2, that only really gives me about 70mm to put the insulation in...... what do we think to me putting the rockwool in place and just compressing it into place?

Good or bad Idea?

 

[foxhole]

I would ply inside, plasterboard will deform if aloud to get damp, unless you are keeping it dry and warm inside during winter.
Easy enough to part rockwool thru the middle to use 85mm thickness.

 

[Harbourwoodwork]

Is this summerhouse more than tea and cakes on a sunny day, that would detemine the spec

 

[bendeneo]

thanks guys,

In reality this will be more than a summerhouse, my plan is for it to be a summerhouse/pub/additional spare room for when people stay over....

So whilst ply makes sense, it wouldnt give the right look/feel.... but I see your point about keeping it warm, perhaps if I am using it once a weekend this wouldnt be so bad....?

 

[Harbourwoodwork]

so Its not just a shed celotex insulation leave an air gap inbetween insulation and osb/bd breathable membrane outside osb/bd ,moisture barrier on warm side of insulation (inside).

 

[bendeneo]

I'm not sure how to best achieve that really.

As before (with the moisture barrier added) this was the planned wall cross section:

- 12mm OSB for the outer skin of the walls
- breathable membrane
- cellotex or similar between the timber
- Moisture barrier
- plasterboard

Are you saying that I should somehow raise the OSB away from the breather membrane?

If so could you give me some more info on what you would suggest?

Will this not negate a lot of the insulation, and allow bugs in?

Thanks!

 

[Harbourwoodwork]

from the inside plasrer/b, vapour barrier,celotex insulation between studs, then air gap before osb/bd(in otherwords if the studs are 4"x2"use 75mm celotex leaving 25mm air gap )after osb/bd,waterproof breather barrier counter battening then final weather boarding job done