# cheapest way to insulate a 12x8 wooden shed



## smiley65

just bought a shed and need to insulate it but need to do it on a budget any help would be great


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## Lazurus

do it properly with house build products other wise damp will be an issue and the cheap option may not give you any benefit, at worst line the inside and leave an air gap / cavity which could be filled at a later date as funds allow..


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## smiley65

thanks for that its been confusing with the amount of different ways to do it from bubble wrap to really expensive things,i have been given a 25mtr roll of builders liner paper which i was going to staple on and my friend suggested loft insulation but at moment can only find 100mm thick and i would need 50mm,then he said go over that with osb or what ever is cheapest then paint it does that sound correct to you


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## MikeG.

The answer is that there is no good way of doing it. This is why I strongly advocate people building their own sheds or workshops rather than buying off the shelf ones. The building paper/ breather membrane should go outside the frame, but it can't because there is cladding in the way. There should be a 25mm gap behind the cladding boards, which typically doesn't leave enough room for insulation. If you can only fit 25mm of mineral wool insulation (plus the 25mm air gap) in the depth of the "frame", then it simply isn't worth the trouble of doing. You'll get no benefit from so little insulation. I don't know what to suggest I'm afraid, other than "don't start from here".


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## ColeyS1

MikeG.":23dabz8q said:


> The answer is that there is no good way of doing it. This is why I strongly advocate people building their own sheds or workshops rather than buying off the shelf ones. The building paper/ breather membrane should go outside the frame, but it can't because there is cladding in the way. There should be a 25mm gap behind the cladding boards, which typically doesn't leave enough room for insulation. If you can only fit 25mm of mineral wool insulation (plus the 25mm air gap) in the depth of the "frame", then it simply isn't worth the trouble of doing. You'll get no benefit from so little insulation. I don't know what to suggest I'm afraid, other than "don't start from here".


Could you put the breather membrane on the inside Mike and build inwards? 

Sent from my SM-G900F using Tapatalk


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## smiley65

hi mike g, unfortunately im unable to build a shed due to health issues so bought a shed from a company who also erected the shed for me, i have been advised by people on how to insulate so electrical tools could be stored and used but no one has said about a 25mm gap between insulation and osb which would go over to cover i will have to look further into it, thanks for responding


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## MikeG.

No, you misunderstand. The gap should be outside the insulation, between the back of the feather-edge boards and the outside of the insulation. And before you consult anyone else, you're already communicating with an architect who has somehow come to have something of a reputation for domestic outbuildings.


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## MikeG.

If it were me (it never would be), I'd fix 50mm Celotex to the inside of the frame, between 45x45 horizontal battens at 600 vertical centres (screwed to the frame), then screw 10mm OSB to the battens. You'd lose a significant amount of internal space, but at least you'd be warm, and there would be some sort of air circulation behind the boards. It's very second-best, but a damn sight better than anything else I can think of for a pre-built shed.


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## smiley65

Again thank you for valuable help also good to know what your on about


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## Inspector

Not as budget friendly but quick and easy is after wiring (unless you are doing surface) would be to put styrofoam on the walls. Tape all the joints and then put the OSB on top with longer screws. You maintain an air gap and can put anything you like on the walls/ceiling but loose a few inches of space. It is a small space so the difference between styrofoam and other materials is minimal. With a decent door and windows if there is any will make it easy to keep the shed warm enough to prevent rust with a small heater dehumidifier.

Pete


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## MikeG.

Careful. "Styrofoam" means different things in different places. In the US it is, I believe, interchangeable with "polystyrene", and that would be something you should definitely not use in a building like this. 

As I said previously, you have to use enough to be worth the effort anyway. An inch of styrofoam is the equivalent of substantially less than 2 inches of mineral wool/ fibreglass, which isn't enough. Not even close to enough. The building would only be usable in summer, autumn and spring. You need to be aiming for the equivalent of 4 inches of mineral wool (2 inches of Celotex) as a minimum realistic thickness of insulation to allow a lightweight building to be used year round. Even this would depend on decent levels of insulation in the floor and ceiling. If you were to go for 50mm, then the battens I suggested would give a more substantial wall, bearing in mind that the structure may just be 2"x 1" battens.


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## Inspector

Yes Styrofoam = polystyrene. Expanded like coffee cups or the more costly extruded. 
I don't see why it can't be used in a shed? As I think I described, the wall cavities would remain allowing air and water that gets behind the outside boards to get out again. The taped foam acts as a vapour barrier and the OSB over it seals it up if a fire got going, at least long enough to get out. If my cooler can keep food cool/warm for hours with a couple inches or less of foam I don't see why it wouldn't do the same in a bigger space. I defer to your greater knowledge.

Pete
PS I lived on the west coast of Canada near Vancouver for most of my life and understand what cool wet climates are like.


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## gmgmgm

EPS (polystyrene) I've found is significantly cheaper than Celotex. Very cheap in fact. It seems to be roughly half as good as Celotex, so is probably cost-effective in most workshops. Easy to get in 25/50/75/100/150mm thicknesses.

It IS a potential fire risk though, so make sure it's covered by something like OSB/hardboard.


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## Darren B

Hi bud. 

I had the same issue. PIR board is expensive, true but effective. I used 25mm rock wool In between studs. I then cladded the lot with pallet wood. 

In my opion 25mm is not enough I would go 50mm with vapour barrier. Or to save money on heating then go for the 25mm PIR board. 

To cover the insulation I would avoid plaster board. It goes soft and soggy after a few years. Especially if unheated. Tongue And grove is mental in price, £400! 9mm ply will be about £240! 6mm too thin. Hence I used pallet wood. 
I’m going to install a small stove to keep me cosy in winter.


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