Planning a workshop build

[Elsmorian]

Hi all,

We recently had our garage replaced (A series of lets change the asbestos roof, oh the roof structure is all rotten, oh well the walls are actually cracked and falling apart ok lets re-build the whole lot!) And am now looking at options for a workshop!

It will be close to a boundary, and roughly 7x3m maximum, so if I've don't my research as long as its under 2.5m and built from non-combustible materials we won't need planning or building regs?

My plan is to get the same people in who did the garage to build a same basic shell (Single skin lightweight block which has been rendered, OSB and GRP roof) and then insulate at a later date - battens for air gap, insulation and then OSB. My thinking is getting tools etc out of the house where a lot of them have been stored since we moved is a priority, as we are expecting our first in 3 months and the nursery to be looks like a bomb site at the moment! As long as it is dry and secure that will do for now, and I can add insulation etc at a later date.

I guess my question is does anyone see any big issues with this? I would love to build it myself but time is a little short, and this way can have something solid quickly that I can then improve on when I have a bit more time(!!)

 

[MikeG.]

3m wide minus block , gap, insulation, lining ..... You'll end up with an internal measurement of just over 2.5m. That's going to lead to some awkward "where does everything go" questions, and a restriction on what you can make in there. Timber frame would save you a lot of space from the footprint.

 

[Elsmorian]

Yeah you are right it would impact the internal space, though the timber frame would be about the depth of the blocks at around 100mm, so say maybe 20mm air gap, the blocks are Thermalight I think so they have fairly ok insulation anyway, so might only need 50mm Celotex or similar and then 10mmOSB, so only 80mm or maybe 130mm each side if 100mm insulation. Could maybe just make it bigger

Looking at the cement board options which I guess is how you would do a timber frame looks interesting though a bit more work with external sheathing and membranes and then render on top if something like https://www.insulationshop.co/10mm_cemb ... board.html is used.

If time wasn't an issue that way would be tempting..

 

[Fitzroy]

My ‘shed’ has ended up 2.85m wall to wall inside and I wish it were 15cm wider that would have given space enough for benches either side and the table saw in the middle. As it is I’m going to have to put most the tools on mobile bases. You live and learn.

F.

 

[Elsmorian]

A few months on and the shell of this build is now completed! I shall post some pictures shortly, but we went with a 2.5x6m rendered single skin construction in the end, areated blocks and an OSB / GRP roof. A bit long and skinny sure, but its what the garden would allow really, and while I will have to break up any full size sheets outside I'm happy with that - its my first proper space and I'm looking forward to using it!

With regard to insulation, the roof joists (rafters?) are quite deep at 150mm so there is plenty of room to put some PIR Celotex stuff in there- as its foil covered is that enough of a vapour barrier or do I need to cover that with OSB too?
I'm thinking that I might also line the inside of the building with 50mm celotex too, it means I loose some more floor space but it would be a bit more usable in varied temperature though the blockwork seems to do a fair job of keeping it a constant temperature. With this I would probably line it as some have on here with a ~10mm air gap, the insulation, then OSB. Anything to bare in mind particularly when doing this?


I will try and include some pictures shortly!

 

[MikeG.]

OK, I'm going for a bit of blatant blackmail here: no photos, no advice.

 

[Elsmorian]

Haha, fair enough. The building went up at the same time as I became a father :shock: , so photos of the build are a bit few and far between, but here are a few I just took now!

I've put on a couple of coats of Weathershield on it, though I think that has made it look pretty harsh so thinking of softening the colour at some point, and maybe getting some plants up the side to break it up a bit, but all in good time.

It's currently half full of stuff we had piled up in the house, but after the inside is a bit more finished it will be quite fun to start building some benches and unpacking tools from the boxes they have been in for a while!

 

[MikeG.]

Fair's fair. Thanks for the photos........now the advice.

If you are using this building only intermittently, only heating it now and then, and not doing any work in there that produces a significant amount of water vapour, then a vapour barrier at the underside of the roof timbers isn't critical. However, as it is so simple and cheap to fit (you could use OSB for the ceiling, or you could use foil-backed plasterboard, for instance), there isn't much reason to not have one.

 

[Elsmorian]

Thanks Mike, that makes sense, I will probably go with some thin OSB - is the foil on the insulation like Celotex designed to be water permeable so any vapour that does get in can get out again?

In regard to the walls is any treatment of them recommended before lining them? I guess not as then the air gap will let them "breathe"!

 

[Stanleymonkey]

Quite a funny thread to scroll through! Planning a workshop build to here it is in a few pages!

Looks good though - you are very lucky. Congratulations on becoming a father too. My little munchkins often come and nick all my small clamps for den building! Don't put those near the door - that's the only advice you need!!

 

[Elsmorian]

Some more work recently, have been putting in the celotex which is going well! (hammer)

I have lifted the supporting timber off the floor about 15mm, and am wondering weather to do the same with the OSB that is going over the top, or to rest that on the floor? I raised the timber up just for airflow at the bottom but not sure this is needed really.. :?: