Dry lining home

KevinG224

Hi, I recently bought a home with a garage converted to a kitchen, there is little to no insulation in this part of the home and I am renovating other rooms and new kitchen being fitted. Should I get this room dry lined or seek external insulation instead? Also can insulated plasterboards be fitted over existing plasterboards? Pumping the walls is not an option unfortunately. Thanks

MicktheMan

Describe your wall makeup from out to inside

KevinG224

I have very little knowledge of the make up of the wall, however I was told there was no cavity that can be pumped. House was built in mid 1970s if that is any help?

MicktheMan

Should I get this room dry lined or seek external insulation instead?

External insulation*

Also can insulated plasterboards be fitted over existing plasterboards?

While they can be physically, it is not at all recommended.

I would expect those walls to be leaking air (and therefore heat) like a sieve so your best bet would be to remove the current lining, getting back to the bare block wall, apply an airtight plaster to the blockwork and externally insulating.

*Not nearly enough information to hand here but in general ewi trumps iwi every time.

KevinG224

Thanks for the feedback. I had one person come out to price the job and tell me they could put the insulated boards over existing but it just didn’t sound right to me. I am due to have others coming this week will query with them also. I was also told previously (not by an expert) that ewi is not as good as the heat could still escape the wall and be held on the outer layer as opposed to staying in the home.

KevinG224

Thanks for the feedback. I had one person come out to price the job and tell me they could put the insulated boards over existing but it just didn’t sound right to me. I am due to have others coming this week will query with them also. I was also told previously (not by an expert) that ewi is not as good as the heat could still escape the wall and be held on the outer layer as opposed to staying in the home.

Shoog

Drying lining done correctly accompanied by appropriate ventilation upgrades can be extremely effective.

Airtightness must be a priority otherwise damp will cause mould behind the plasterboard.

Calahonda52

https://www.boards.ie/discussion/comment/122603956#Comment_122603956

Complete xollob and don't do it.

!970 garage for my mula will be cavity block.

EWI all the way, making sure the top of wall under the wall-plate is sealed

Calahonda52

https://www.boards.ie/discussion/comment/122603963#Comment_122603963

Airtightness must be a priority otherwise damp will cause mould behind the plasterboard.

In the interest of knowledge sharing as we increase the use of more advanced materials

there are two separate ideas at play here.

The A/T layer is to stop uncontrolled ventilation and hence reduce heat loss.

Then we look at what is used as the (moisture) vapour control layer. (VCL)

The A/T layer and the VCL may be the same item, but the actual product selected depends on the actual wall buildup, as VCLs range from sd values of 1 meter (vapour open) to

1500 m vapour tight.

Some are also bi-directional, depending on the climate conditions.

Finally on IWI vs EWI

the heat loss through an uninsulated wall helps in keeping the wall dry

IWI reduces this, leading to wetter walls

EWI, with na proper rain shield, prevents this.

Less IWI is recommended than EWI so as the dew point stays inside the wall and moisture is less lightly to condense on the surface

Shoog

You have to effectively tank the room and then control humidity with active ventilation. This is a possible strategy which if done correctly (MVHR) will retain more heat in the house whilst reducing the potential for condensation.

KevinG224

Ideally, EWI would be the option, however as there is quite a bit of reno work needed internally i.e a new functioning kitchen I am trying to be as cost effective as possible. I know about grants for EWI but that would require the whole house being done and at this stage that is way out of budget unfortunately. My main focus now is to get the kitchen to good standard including walls. I may look into EWI on this part of the home without the grant however (probably more expensive than IWI)

Shoog

https://www.boards.ie/discussion/comment/122604866#Comment_122604866

External insulation is likely to cost 3-4x that of internal - even after grants. It's brutally expensive. It's definitely the better job but can you afford it.

However I would repeat - you need to budget for suitable ventilation in a wet area such as the kitchen.