Converting timber stable into a workshop

[Boxcloggs]

Hello all. First post, so please be gentle.
In the next month or so I will be having a set of timber stables delivered and erected. It is a block of 9, but my wife has 'graciously' allowed me to have the end 16x12 ft store as a shed/workshop.
The stables are constructed of 4x2 stud work, clad with 19mm x 125mm ship lap, bolted to a single course of bricks on a concrete plinth. Onto these stud walls are roof trusses are 5x2 purlins, boarded on top with 11mm OSB which supports onduline sheet roofing.
My plan was to simply line my workshop with 9mm ply and slap on a bit of white paint before putting up a few shelves, but a quick bit of Googling a few hours ago has brought me here. I seem to have opened Pandora's box and decended into a world of vapour barriers, breathable membranes, insulation and French cleats! This has left me extremely confused and (having looked trough some WIP and project threads) feeling wholly inadequate as a man.
My current shed is just filled with rusting/broken tools, dried up paint tins, *** ends, spiders, broken promises and despair. However, I sense an opportunity to make a fresh start with this new workshop, and I'm hoping that someone on here might be able to help me out.
Structurally, I will need to work around what's there. This workshop will share a partition with the adjoining stable but the trusses above the partition will be open, so I suspect I'll need to close that up, or else it will negate any insulation I put in (with the added bonus I suppose that it'll isolate the smells/dust generated in the workshop from getting to the horses).
I have no idea what I'll use the workshop for, other than for a quiet place to cry when the bill for the stables arrives, but who knows what I might be doing down the line and I'd hate to to a bodge job now and regret it in the a few years.
So, given the simple cladding directly onto studwork construction, what should I consider doing to bring it up to a decent spec?
Thanks in advance.

 

[AJB Temple]

Rusting tools is your clue....
Welcome to the forum.
It is worth insulating your workshop, including the ceiling / roof before you install internal cladding. A freezing damp workshop does not get used in winter and wrecks your tools.
You need to make sure you have ample power supply and plenty of lighting. I would over spec your power supply and include at least one 16 amp circuit.
If you can beg borrow or add an additional small room, you can use it for timber storage (workshop no use without wood) and possibly house your extractor (they are always noisy).

 

[donie]

I'd try and insulate it if possible, for a workshop you don't need much. A foil backed slab should keep out moisture. Definitely block off area from the horses, also to block the smell of them in the workshop. Would noise from machinery spook the horses? Do you care?

Sounds interesting!

 

[Boxcloggs]

Thanks for the replies, definitely food for though. I'm still gathering as much information as I can from the various threads in here as well.
As the stables are already a done deal in terms of construction, I think what I should probably do is post some pics when they're built. That way you will be able to see what I've got to work with, and as I am a complete novice at this, maybe give me a steer as to how I can make the most of it.

Thanks again.

 

[donie]

Pictures always help!

 

[Boxcloggs]

Day one of the stables being built. They've started at the workshop end, so i will now try to post some pics so you can see what i have to work with.

 

[MrTeroo]

I would do your back a favour and cover that concrete floor in foam floor tiles if you intend to spend long periods of time standing in there.

http://www.ebay.co.uk/itm/MCR0919-S...hop-Matting-/152455944045?hash=item237f15176d

Brushing a couple of coats of PVA over the concrete first would also not be a bad idea, to keep the concrete dust down.

 

[gmgmgm]

Looking good. I'm about to "requisition" some stables as a workshop so watching closely. I'm planning to line with OSB, for a "woody" look, rather than white paint.

I'd echo the previous points about plenty of power and light.

What are you planning to do with the rough concrete floor? Most of my heavy machinery is on wheels, and I need to find some way of smoothing my floor. Various threads on here cover putting down a screed or a wood/laminate floor on top.

 

[Boxcloggs]

Apologies for the delayed reply and thanks for all the advice so far.

In a couple of weeks I'll be ready to get cracking with this, so I thought it time to make a plan!

1. Make a ceiling. Simple 3x2 CLS on top of the existing stud work. Centres to match the studs and some noggins for strength. The width is slightly under 3.6m so this should be fairly straight forward.

2. Insulate walls and ceiling. I have some loft insulation left over from my house build so may use that. Will this be ok, or should I go for a kingspan type foam? I have 4x2 stud walls, so what foam thickness should I be looking at (I understand I'll need an air gap between the foam and the cladding).

3. Moisture barrier. Any type I should be looking for? Would kingspan with a moisture resistant backing remove the need for this?

4. Lining. Either OSB or ply depending on how the budget looks. Approx 10mm thickness.

5. Electrics, lighting and rubber floor mat.

How's this sound?

 

[paulm]

I'm interested in this also, particularly the insulation aspect and whether a membrane serves any purpose as there won't be any air movement between the insulation and cladding.

My own similar project is to insulate and clad a 20' x 12' timber shed to provide a modest workshop. The shed is already pre-built so have to just figure out the best approach given the limitations of what's already there.

 

[deema]

For the floor, I would place cover it in a damp proof membrane and then place 75x50battons in a grid and fill the voids with insulation. OSB or other similar cheap 18mm covering will provide a smooth, insulated, suitable for machines and foot friendly floor very cheaply. Fence rails often are the cheapest solution for battins hence 75x50!

I would not put up a ceiling, as height when moving stuff about is really good to have.

Since the construction is defined for the walls and ceiling I'd fill between the studs with insulation and then board over. You will need to isolate yourself from the horses to avoid the condensation that they generate playing havoc with your shiny tools.

 

[Boxcloggs]

Hello again and thanks for the replies.

Floor: for now, a rubber mat / floor tiles will do. I'm hoping to put up a garage soon, and the workshop will move into this and this room will be given back to the stables.

Ceiling: I'm not too fussed about the height as I won't lose (and don't need) a significant amount.

Insulation: Confused. Still torn between foam and rockwool-type. The cladding is not airtight, so there will be some movement of air behind the insulation. Will there be enough circulation/movement of air between the cladding and insulation to justify the extra expense of using foam in order to leave an air gap?

Membrane/barrier: Still confused. Again, the cladding is not airtight, so moisture will get through this and penetrate into the studs. Surely I need to stop any moisture getting from the studs onto the internal OSB/ply lining? If I put a moisture barrier behind the OSB/ply, will I create a problem by trapping moisture inside the workshop? Would I need an extractor fan in this instance?

Lining: there's a fair cost difference between OSB and ply. Which thickness of each should I be considering? Any shelving etc will be screwed into the studs, so there shouldn't be too much weight for it to carry.

Thanks in advance for any advice!

 

[Student]

The guru for anything to do with workshop builds, including insulation etc, is MikeG who posts on this forum and also on Wood Haven 2. There's a lot of useful advice contained in this thread

build-a-shed-mike-s-way-t39389.html

 

[Woody2Shoes]

Hi,

I'd use 9mm OSB3 instead of ply. Cheap, probably marginally less environmentally unfriendly than ply, and designed for this sort of job. The only downside is it's dense and therefore adds a fair bit of weight.

OSB is in theory pretty vapour impermeable so you could arguably get away without a separate vapour check membrane - I'd be tempted to put one in anyway - it needs to be on the warm side (i.e. inside) of any insulation. The whole point of a vapour check layer (usually just thick PVC sheet with taped edges) is to stop interstitial condensation - where warm damp air from inside drops some of its moisture at it cools on its way out through the structure. Keeping rain out is a completely separate consideration and you're right to assume that your outer cladding will not keep out all moisture - it therefore needs a ventilated airspace behind it so any rain/snow that does get blown in can evaporate and be carried away by the outside air.

https://en.wikipedia.org/wiki/Interstitial_condensation vs https://en.wikipedia.org/wiki/Rainscreen

Cheers, W2S

PS the best performance for a given thickness is the foil-covered rigid PU foam boards eg Celotex - personally, I wouldn't bother with anything else (for example, rockwool can be a pain to work with).

 

[MikeG.]

Sorry I'm late to this. I'm run off my feet trying to stay ahead of the plasterer, and I've only just sat down for the day.

Insulation: Confused. Still torn between foam and rockwool-type. The cladding is not airtight, so there will be some movement of air behind the insulation. Will there be enough circulation/movement of air between the cladding and insulation to justify the extra expense of using foam in order to leave an air gap?

Your choice. Celotext is roughly twice as efficient an insulator as mineral wool (fibreglass) if properly fitted, but fitting it properly is a pain in the bum. In you situation, which is far from ideal, I would certainly fit Celotex because there is no battened-out zone outside the studs, and no membrane, so it seems the only feasible way of maintaining an airgap behind the boards. A membrane in your circumstance is pointless, other than to hold up mineral wool insulation. Ideally, the membrane would go over the outside face of the studs which would then have a counterbatten over them, and the boarding fixed to that.

Membrane/barrier: Still confused. Again, the cladding is not airtight, so moisture will get through this and penetrate into the studs. Surely I need to stop any moisture getting from the studs onto the internal OSB/ply lining? If I put a moisture barrier behind the OSB/ply, will I create a problem by trapping moisture inside the workshop? Would I need an extractor fan in this instance?

Some fundamentals. A heated building is wetter inside than out. Read that again.........it isn't a mistake. Therefore you need a barrier to vapour getting into the walls from the inside, not the outside. Any moisture that gets in from outside behind the boards will be dried off by the airgap, because I am going to ask you to put in ventilators into each "panel" formed by the studs. Dealing with moisture "attempting" to get into the wall from the inside is more important. OSB is a very efficient vapour barrier. It is fully of glue, and allows very little in the way of moisture into the wall behind it. Celotex is the same. Combine the two and there is absolutely no need whatever for a formal vapour barrier. When you fasten OSB in place, leave a small gap (say 2mm ......I use a nail as a spacer) between each board (which obviously have to join at a stud). Make sure your insulation is hard up to the inside of the OSB lining. The Rolls Royce solution in your less-than-ideal circumstances would be to put Celotex between the studs at a depth 25mm less than the depth of the studs, and then to put another layer across the inside face of the studs, 25mm deep, unbroken, then a lining of OSB over that. If this were for an office or a professional workshop in use year round, that's what I would specify.

Lining: there's a fair cost difference between OSB and ply. Which thickness of each should I be considering? Any shelving etc will be screwed into the studs, so there shouldn't be too much weight for it to carry.

9mm OSB is all you need. Anything with any weight should be screwed into a stud, or onto a batten screwed across a number of studs. Don't bother with ply: too much money, no great improvement in performance over OSB.

 

[MikeG.]

Boxcloggs seems to have vanished.

 

[paulm]

This is a really interesting thread, not least as I am just about to start something similar to the OP with a repurposed existing large shed.

I've been looking at the celotex/kingspan vs rock wool question too. My presumption was in favour of the celotex but, there appears to be around six week lead time at the moment due to demand exceeding supply, and then when I contacted celotex to check on the noise reduction aspect of their boards versus rock wool, I was told the noise reduction was negligible, the board almost acting like an amplifier if anything, which has really thrown me.

On the other hand there are rock wool acoustic products especially designed for and apparently good at noise reduction.

I do need to manage possible noise issues due to near neighbours, but also want to be thermally as good as possible of course as the workshop will be used all year round as well as wanting to ensure tools, equipment and materials stay in good condition.

The existing stud walls are based on 75mm x 50mm studs, so to leave an air gap (and ventilation holes in the external cladding, covered with insect mesh) between the external cladding and the insulation of around 25mm, the insulation being membrane and rock wool, or celotex only, only allows for 50mm of insulation before the 9mm OSB boarding.

Now unsure whether acoustic rock wool at that thickness will have any meaningful thermal efficiency (the celotex would be twice as effective at the same thickness), but no point it being decently warm with celotex if I can't use the workshop much due to noise and annoyed neighbours !

Maybe a compromise would be acoustic rock wool 50mm (with supporting membrane and air gap to external cladding) and then 25mm celotex across that (and the studs), and then the 9mm OSB. Would lose a bit more internal space, and add some cost and possibly delays in sourcing the celotex, but if that would give worthwhile improvements I guess I would probably go for that ?

Cheers, Paul

 

[MikeG.]

Don't bother with acoustic mineral wool. The ordinary stuff is almost as effective. Also, I don't think many people buy new Celotex when there is so much "seconds" quality stuff kicking around. Depending on where you are in the country, there will be a cheap supplier near you. Your compromise suggestion is a good one, except for the fact that nothing will hold the rockwool up. It will slump, and you'll lose both your air gap and the completeness of your insulated envelope.

 

[paulm]

Thanks Mike. If using mineral wool it was going to be with a battened out and membraned inch gap between the existing external cladding and the mineral wool. Is that still likely to slump ? I've seen mineral wool "batts" I think they're called which might be better if slumping is likely ?

Sorry to the OP, hope it's not hijacking your thread and of some use to you too !

 

[MikeG.]

Such a discontinuous membrane's only use is supporting insulation, and yes, batts stand up much better than rolls.