insulating internally solid wall

[b21playa]

hi all

Ive got a downstairs wc which is only 1.7m wide internally.

I want to insulate this, but with something that will not redue the width too much.

wall construction is 9: double skin wall, no cavity, outside is rendered.

The walls are currently bare, was thinking of sand cement plaster, batten and board with polystyrene insulation, batten and board with cavity type insulation, thermal board, dot&dab.

 

[geezer5555]

hi all

Ive got a downstairs wc which is only 1.7m wide internally.

I want to insulate this, but with something that will not redue the width too much.

wall construction is 9: double skin wall, no cavity, outside is rendered.

The walls are currently bare, was thinking of sand cement plaster, batten and board with polystyrene insulation, batten and board with cavity type insulation, thermal board, dot&dab.

i would not dot and dab a 9inch wall as Solid brick walls can be penetrated by rain . i would batten and board and i would use tri iso 10 insulation it is 30 mil and equivalent to 210 mil of rock wool ..
i found this link for you
http://www.just-insulation.com/super10.html

 

[alittlerespect]

Hi

Use a kingspan, celotex, british gypsum or similar PIR insulation board with a plasterboard finish.

PIR has a good vapour resistance and you will not require a vapour proof membrane and any penetrating moisture through the wall should not become a problem. Follow manufacturers specification and stick the boards onto the wall with dabs.

For any real benefit you will need 50mm thickness of insulation which will give a finished board thickness with plasterboard and skim coat of around 65mm.
However, if you want to go the extra mile use a board with around 80mm - 100mm of insulation -100mm would be the maximum as the law of diminishing returns starts to kick-in!

Regards

 

[ajrobb]

Kingspan K17 is intended for dot and dab mounting to cavity walls but not solid walls.

Kingspan K18 is intended for batten mounting, including on solid walls.

 

[ajrobb]

Kingspan K17 is intended for dot and dab mounting to cavity walls but not solid walls.

Kingspan K18 is intended for batten mounting, including on solid walls.

 

[alittlerespect]

Hi

A bit more detail on insulation assuming solid wall construction with average exposure U value 2.1W/m2C

Add 25mm PIR insulation improves U value to around 0.66W/m2C

Add further 25mm PIR insulation improves U value to around 0.40W/m2C

Add further 25mm PIR insulation improves U value to around 0.22W/m2C

If you want to go the extra distance add a further 25mm insulation improves U value to around 0.18W/m2C

As previous note - diminishing returns kick in and most people would probably not wish to go beyond 100mm of PIR insulation.

Ohh! Final comment - if your looking for an insulation board for solid walls check out Celotex PL3000.

Regards