Shed in a barn

[Chris152]

I'm going to build a workshop that'll sit inside a metal barn. It'll sit toward the back of the bay shown in this photo

The front face will be in line with the second rsj back from the front of the barn, and will be 4.3 (wide) x 4.6 (deep) x 2.6m (tall - the ceiling will be well short of the top of the barn).
In my mind it'll be a studwork construction using 100 x 47mm timbers at 60cm centres, 50mm celotex in walls and on the ceiling behind OSB. OSB will only be on the inside of the shed. Air will be able to pass between the studwork/ insulation and the wall of the barn. There'll be a layer of dpc between the floor plates and the concrete floor. That's as far as I've got and as some of you might discern, I've little knowledge how best to do this.

The existent walls and roof of the barn are water tight. Do I need to use membranes/ think about further ventilation between the insulation and the internal osb? What other things am I overlooking? An electrician will be taking care of power/ lighting.

Any comments or advice very welcome!
Thanks
Chris

 

[MikeG.]

No, that's fine Chris. Crack on as planned. Just locate your studs to align with your ceiling joists and you'll only need a single wall plate, and make sure your insulation is hard up against the OSB so as not to create unventilated voids. You could put the OSB in place first and push the insulation in afterwards, hard up to it.

 

[Chris152]

Thanks Mike, that's great.

 

[HOJ]

I had a workshop in a similar type of farm barn, for years, using the same principal of insulated stud walls, however, I put in a structural joisted ceiling, with a steel I beam to split the span, and made a mezzanine/lofting floor, with about 2 meters of headroom, which was an ideal place to build and store larger items that we had made.

 

[nabs]

can I ask a daft question? Why is it important to avoid a gap between the insulation and the inner OSB?

 

[MikeG.]

It's not critical, it's just good practise. Dead air pockets could in theory lead to interstitial condensation and mould growth. You have to remember that the advice I give on public platforms like this might be read be people who apply it in different circumstances, without referencing it back to me, so I try to give good advice which can apply generally. Besides, as I was always told, if a job's worth doing, it's worth doing well.

 

[nabs]

thanks Mike, I did have more than a passing interest as I have just moved house and I am vaguely thinking about insulating part of my new garage , the exterior wall of which is a half brick
thick construction, with wider intermittent internal piers. So my question was (indirectly) about whether I would need to fill the entire gap between the piers.

I am also planning a shed, which I shall endeavour to do the 'Mike way'. Separate posts planned on both these topics once I get a bit more organised!

 

[Chris152]

I had a workshop in a similar type of farm barn, for years, using the same principal of insulated stud walls, however, I put in a structural joisted ceiling, with a steel I beam to split the span, and made a mezzanine/lofting floor, with about 2 meters of headroom, which was an ideal place to build and store larger items that we had made.

Using stronger timbers for the ceiling is a good idea - I don't think I'd want to spend much time up there but for some storage, definitely worth thinking about. Thanks.

 

[steve66]

I’m in the process of putting my shed in a barn, and filling with insulation, air gap behind stud, one bracket off wall in centre to stop any spring in wall

 

[steve66]

Stud wall with house wrap, just retro fitting stud wall in timber frame construction

 

[steve66]

Insulation placed in behind plastic webbing to hold in place before top board

 

[steve66]

Doing these attachments on phone and photos showing upside down until you click on them for some reason

 

[loftyhermes]

I've often dreamed of doing this but my dream was to insulate with straw bales all around the outside of my timber frame, assuming that my lottery win would buy a big enough barn.

 

[clanger]

Doing these attachments on phone and photos showing upside down until you click on them for some reason

I did wonder when the floor had a very dramatic scope to it. I worked it out when I saw that you had screwed your hammer and screw box to the ceiling