Shed/Workshop Insulation

[motownmartin]

I have just built this small workshop down the garden and have some foil faced Celotex insulation boards arriving on Thursday, what I want to know is how do I fit them.
Do I fit them up against the tongue & groove or do I leave a gap or will it not matter.
Its mainly for soundproofing but still want to keep the damp out.

Just to show you the inside of the workshop here is a pic

 

[markwuzere]

i would leave a small gap between the t&g and the insulation although others will probably say it doesn't matter. i would also doubt the sound proofing quality of celotex but on this im no expert as i refuse to use the stuff (multi foil every time for me)

 

[Triggaaar]

Do I fit them up against the tongue & groove or do I leave a gap or will it not matter.

Its mainly for soundproofing but still want to keep the damp out.

Unless you have nothing else and don't want to spend anything I wouldn't use it for soundproofing. It's no good (for sound) and those sheets are expensive, because they are good for heat insulation. You'd normally have something between the weatherboarding and insulation, like breathable felt and ply wood, and the insulation would go tight up to the ply wood. If you have nothing between the two, perhaps leave a gap between the weatherboarding and insulation. This wouldn't be the normal method, but you don't really want any drops of water running down the insulation. Loft fibreglass insulation is currently 3 for the price of 1 at DIY stores (government initiative) and this would be better at soundproofing (although still not as good as dense soundproofing boards).

In fact, looking at how thin your studs are, perhaps you should get the dense sound proofing boards. It's not a big area.

 

[crazylilting]

I put up 35 mm kingspan on my tin roof and it has made a bit of a difference for sound proofing. When it rained before i could not hear the radio and now i can so i definitely know it has made some difference.

The thicknesser is the loudest tool i have, but my partner says it's not so bad with the insulation. I was thinking of putting another layer but now i think i'll look into sound board. I'm not to worried about the noise of the tools as i only work in the shop during the week when everyone is at work any how, but i don't like to hear outside noises while working.

 

[motownmartin]

Unless you have nothing else and don't want to spend anything I wouldn't use it for soundproofing. It's no good (for sound) and those sheets are expensive, because they are good for heat insulation.

Whoops, already bought the stuff, half price though, soundproofing is perhaps the wrong word, more like keeping the sound down as its 35 metres from the house, it'll keep me warm in the winter another reason for using this celotex was ease of fitting and don't need any other boarding which can be quite pricey

 

[MikeG.]

Triggaaar has it right (bar the advice about ply outside the insulation!). There should be a gap between the insulation and the back of the boards. This isn't really a subject for a poll......I'm afraid that you should be taking the advice of people who know, rather than the distillation of multiple viewpoints.

It will help with sound reduction, but not as much as other forms of insulation......but what a hell of a difference you'll notice when working in there in the winter!

Mike

 

[motownmartin]

Thanks, much appreciated

 

[Triggaaar]

bar the advice about ply outside the insulation!

Why's that Mike? Sure you'd want something on the inside too, but I've had it specified on the outside for timber frame buildings. Possibly mainly for strength reasons (which I appreciate isn't an issue with this case). I pressume it also helps with weathering and draftproofing.

 

[crazylilting]

This has been bugging me... Why do you want an air space in the walls?

If you take a butyl caulk on all the stud work against the siding and put in the kingspan with foil you have essentially made a vapour barrier.

I have never seen an air space in a wall cavity so i wonder what the purpose of it would be...

Thanks

 

[MikeG.]

bar the advice about ply outside the insulation!

Why's that Mike? Sure you'd want something on the inside too, but I've had it specified on the outside for timber frame buildings. Possibly mainly for strength reasons (which I appreciate isn't an issue with this case). I pressume it also helps with weathering and draftproofing.

Triggaaar,

ply is highly vapour-resistant. Sheathing the outside of an external timber frame is effectively putting a vapour barrier on the cold-side of the insulation, thereby trapping condensate on the outside of the insulation. Not a good idea!!

If you need ply in the construction in these circumstances, it should be on the warm side of the insulation.

Mike

 

[Jake]

I posted something similar last night but then deleted it, because I wondered whether all those plywood and OSB sheathed timber frames in the world can be built that incorrectly? What about SIPS?

 

[filsgreen]

I've put 50mm Kingspan between the external wall and 12mm shutter ply, the thermometer has not dropped below 52F. Here is a pic.

 

[motownmartin]

I've put 50mm Kingspan between the external wall and 12mm shutter ply, the thermometer has not dropped below 52F. Here is a pic.

Have you done anything with the windows

 

[filsgreen]

The windows are going to be covered with perspex to provide additional insulation and security.

 

[aesmith]

This has been bugging me... Why do you want an air space in the walls?

Assuming its shiplap or similar construction, there's likely to be a little seepage between the boards in driving rain. If the insulation's hard up against the inside of the boards that wouldn't sound too clever to me.

 

[crazylilting]

Do you put a gap at the bottom of the sheets for run off to? I wouldn't of thought the siding would be so poorly done since most times people don't even put any insulation in them, by the sounds of it they aren't that weather tight?