Insulation/renovating a cupboard

In our bedroom, we have a walk in cupboard that hasn't really been touched since the house was built - fairly sure the plaster on the walls is the original. It is located on the exposed corner of the house, and it is worth noting that the side wall has cavity wall insulation, but the upper half of the front wall does not. The outline below makes it look huge, but I suspect that is because it sits within the inner skin of the bulding.



We had a bit of a mould problem in there some years back which was partly down to damage on the front corner of the soffit thanks to BT lashing their wire on there and allowing rainwater to get in. That was repaired and I used anti-mould paint on the inside of the cupboard (pre-treated with stain block), however some of it has now crept back.

Generally, the cupboard has one shelf, above head height which is fine, but it is not the most flexible space - as a result, it gets all sorts of rubbish stuffed in it. You know, the sort you shove in a cupboard, don't look at for five years and then when you do open it, you shove it back in due to lack of time or just in case you need it....

I am on the verge of gutting this cupboard out and was wondering what best to do, for the least amount of outlay possible. Included in that would be adding a second shelf and potentially replacing the original one.

I am aware that you can get thermal laminate sheets which are basically plasterboard and an insulation board stuck together - so wondering if these are the answer, to simply remove everything from the cupboard, and add these sheets to the two external walls using dot and dab, line with lining paper, then install new shelves using long fixings so they go through to the original wall?

Insulation boards on their own are cheaper, but they would need plasterboard (or hardboard?) on top and then lining paper.. by which time, I think the costs are the same or more than the first option?

Open to suggestions here, but my current thinking is that some form of insulation is needed here?

 

I was wondering that too - toyed between roughing the surface up with 40 grit first and then maybe stabilising with a coat of SBR?

 

Oh I don't know what one you are thinking of...

This is SBR - Amazon.co.uk

 

Ah, yes - I think SBR is a form of PVA but has bonding agents in it too.. I was thinking it would help with bonding the boards onto the walls.

 

It has been plastered - so plaster direct to brick. I wasn't intending using polystyrene though, it is PIR I believe (so basically the same as Celotex)

 

It is definitely a factor, however I rent this so whilst I am on an agreement where I do maintenance, adding in an extractor is not on my bingo card - not least given the distance to the consumer board to have it wired in. We now run a dehumidifier on auto on the other side of the louvre doors, so I am hoping that with some insulation and the dehumidifier, plus adding carpet tiles to the floor of the cupboard, that we will be in a better position.

 

No, definitely not encroaching into the room - it was replastered in 2007 along with the bulk of the house - the cupboard is one of very, very few areas that hasn't been done and is still on the same plaster it was when it was built (50's at a guess); the intention is to purely make that cupboard a bit more usable to be honest. Getting some sheets up should be fine with help, so not overly worried - although given the size/shape of the cupboard, I think it will be best to measure, cut outside and then carry up smaller sheets.

There isn't a problem with damp as such - a bit of condensation, possibly, but no actual damp - so I am not overly concerned about it bleeding through (although very good point on the silicone as it can do no harm)

The boards I've been looking at are also known as thermal laminate

https://www.matsonsonline.co.uk/pro...-plasterboard-laminate-2400x1200x22-5mm?gQT=1

I didn't consider a vapour barrier, but would adding one not negate me simply dotting and dabbing these boards on? Adding framing to take them is way beyond where I am willing to go - I'd rather simply repaint it and ignore it for another five years.