Insulating solid wall bathroom

[Bruv]

I need to insulate internally two external walls of my ancient solid wall bathroom.
Any cost affective suggestions would be very welcome.
I have thought about wet wall on top of batoned wall with 20mm insulation board between.
Or tile backer insulation board straight on the wall and then plastered, but not sure if that is possible.

 

[Bruv]

Has this topic been done in full somewhere ?
Or is this forum very slow ?

 

[mikeey84]

I would suggest posting this in the building forum.

Generally your plan sounds ok, but it will not be up to building regs.

You will need to be very careful in regards to vapor penetration, as obviously in a bathroom there will be lots of warm wet air looking for a cool surface, and if it gets behind the insulation it will cause a lot of issues

 

[JohnD]

Are you going to tile it?

Rigid foam insulation boards are about twice as effective as the same thickness of mineral wool, so would be your best bet.

I don't think you need any plaster, so you could hack that off to maximise depth of insulation and minimise instrusion into room.

Have a look at the Knauf and Kingspan websites, they make various insulated construction boards and there is probably a suitable one.

 

[Bruv]

My apologies, I have almost finished the bathroom now.
I bought 20mm tile backer boards for the walls and 6mm boards for the floor off Ebay. I have plastered it with multi finish plaster, then refitted basin and toilet, still have to decorate it but don't think it will be tiled at this stage.
Just have to wait for winter now to see how it works.

 

[mikeey84]

Which tile backer boards did you use?

I am thinking of doing the exact same thing at some point this year, so looking for some reccos on material

 

[Bruv]

Which tile backer boards did you use?

I am thinking of doing the exact same thing at some point this year, so looking for some reccos on material

Here is the website http://www.livingheat.co.uk/
I saw them on Ebay and phoned for advice and to order, delivered by Parcelforce two days later.
I don't know if they are brand named but were sold as Cement Coated Insulation board 1200x600.I bought 12 @ 20mm and 7 @ 10mm not 6mm as I said before plus 200 Cement board washers to fit them on the wall, all for £242.90 which I was happy with.
If you go on to plaster them, I thought a plaster mixer paddle at £18 was too much for a one off job, but it is well the investment, and you can get one off Ebay for a lot less.