Single skin insulation (internal)

[Grenage]

Hi Chaps,

The previous owners extended the back door out past an external cupboard, making a small area of the kitchen single-skin - the cupboard. It's bloody freezing, and whatever insulation they put in there was poorly done and ineffective; I'm going to rip it out and do it myself.

I was going to put some 50x50mm battens against the wall, then 50mm foam insulation, then a damp proof membrane, followed by foil-backed plasterboard.

But the wife wants shelves.

Can I put up 50x50mm battens, put 50mm insulation between, then add the membrane and board? I can only really afford to lose 100mm on the two walls.

If I went with the original plan, would I need to put in a couple of airbricks for the cavity. If I did the second, is the lack of a cavity likely to cause problems, and the battens transfer the cold too readily?

 

[BigIan]

Firstly... At least the wife told you about the shelves before you did the work. Mine does it just as I finish off decorating.

Secondly have you considerd external insulation? Fitting this can often be a better option when it comes to single skin walls as it helps to deal with the damp issue that can be caused by the lack of cavity whilst adding thermal performance. In your case it also dosent reduce internal space.

On a third note, perhaps sealing the wall then dot & dab an insulated plaster board?

 

[Grenage]

Hi there, thank you for your reply.

I considered external insulation, but think it might look a little odd in contrast to the rest of the brickwork on the house - it would also bring the wall out past some patio doors, so it's a bit of a non-starter.

I hadn't considered sealing the brickwork on the inside; is that likely to cause other issues? It sounds like a good option. There seem to be several ways people insulate single skin walls; some people say you need a cavity, while others say you don't.

 

[BigIan]

There are many ways to do it, and in all honesty it depends on the nature of the wall you have, positioning of damp proofing, levels of air flow through the internal of the building and many other factors. There are people who are paid huge sums of money to design methods of dealing with this kind of situation.

I mostly wanted to make you aware that this sin`t as simple as simply screwing some kingspan to the wall and plaster boarding over the top.

If it was me....

I would consider fixing some tiber battens to the wall with sheeps wool insulation inbetween over laid with a breather membrane then maybe some 20mm battens fixed horisontally to allow a void for services to run and lime plaster over a wire mesh.
That should be suitably breathable and provide you with some thermal performance.

 

[Grenage]

Hi Ian,

Cheers for your reply. As this is a corner cupboard, there won't be any services running through. Is there a particular reason to use wool rather than polystyrene?

 

[BigIan]

Natural fibre insulations have the benifit of being brethable and are generally recomended for retrofit to older buildings; their hygroscopic properties allow them to buffer the amount of moisture that transfers through the wall structure, which can help to prevent damp patches whilst allowing the external wall to behave as it was "designed" to.

there are other prodicts on the market but my experience is in sheeps wool.

 

[Grenage]

Ah thank you.

I know that sheep wool is pricier than most man made material, but as this is such a small area, It wouldn't have much of an impact!

 

[michaelbailey]

make sure you use breathable membrane if you use standard dpm you`ll get black mold . membrane first then battens then insulated p/board screwed keep a space between board and the wall to maintain a void