insulating a 9" brick wall

[DanDIY]

I know that similar questions have been asked before, but I am a bit confused, so I have made some sketches to try and remove any ambiguity.

I have a solid 9" brick wall on a victorian terrace. I would like to insulate it. I am proposing to make a framework and fill it with Kingspan or similar. Ive made some sketches below which I think show what I mean.

The room is a kitchen, so by building this framework it would also make it easy to do the various cable runs for the sockets, oven etc. And there is a lead water main that comes through the floor in an area where there are no units so it would also help with boxing this in. These are the reasons for me wanting to do this type of installation. I was planning on using 600mm centres on the framework so that I know that ive got a solid fix for my units and also it would tie up with 8 x 4 plasterboard sheets.

After reading up on the subject I am now not sure that my plan is right. A lot of people talk about damp, There is no damp in this wall at the moment, it is very dry considering the age of the house. Could my installation method could cause damp as there is no gap between the wall-framework-plasterboard?
Is there any other issue that anyone can see?

I was hoping to get cracking on this tomorrow. [/quote]

 

[AronSearle]

It may or may not create damp.

Helpful no?



"generally" 50mm of insulation will be ok, with a VCL. Not enough insulation to completely stop the heat loss drying effect, enough to make a noticeable difference.

VCL on the warm side will stop internal moisture passing through and causing damp, externally moisture may come in from the brickwork, which will depend on the brickwork, seals around windows and pipes etc where moisture may penetrate, geography and exposure.

Also http://www.english-heritage.org.uk/...g-solid-walls/eehb-insulating-solid-walls.pdf

 

[DanDIY]

Thanks for the link. I have had a read through. The installations in the english heritage document all show the current plaster intact. Is there a reason for this?

Ive taken my plaster off and was planning on attaching the batons to the brickwork directly. The plaster wasnt very good to start with, and I fugured that I'd claw back 10mm of the space I was going to loose by insulating!


50mm would be the max id install, I was actually thinking of trying 25mm.

 

[jeds]

Your spec is fine as long as you include a vapour control layer. Tack a sheet of 1000g poly to the frame/insulation before fixing the plasterboard. 600mm centres is also ok as long as you use 12.5mm plasterboard. 25 insulation mm is better than nothing but isn't that much. 50x50 battens with 50mm insulation would be much better.

 

[TheVictorian]

Use your spec but apply 100mm wide aluminium tape over the timber and joining both sides of the insulation. This will provide your vapour control layer.

 

[DanDIY]

Bumping an old thread. I am now ready to start this work.

I was looking at various membranes to keep the moisture out and also reading stuff on the net....which has caused even more confusion!

Would a breathable material such as the breathable roofing membranes be suitable? I know they are more expensive than damp proofing PVC, but I would have thought it best to let the wall have an oppotunity to dry out, rather than potentially being permanently damp.

Also I have been given mixed advice with regards to where to put the membrane. A friend I know has insulated a few old houses and put the membrane tight against the wall behind the batons, on the cold side. English heritage in their book and the advice above states to put the membrane over the insulation on the warm side.

I guess it depends on whether I am expecting damp caused by condensation from within the warm room, or damp coming through the old wall....

 

[Grenage]

You don't want a breathable membrane on the warm side, you want a vapour control membrane - to stop the water in the air reaching the cold wall. If you were going to use a breathable membrane, it would be placed on the cold side - but it would be in addition to the vapour control membrane.

Regardless of what your friend has done in the past, make sure the vapour control layer is on the warm side.