Dwarf wall insulation

[mellie_man]

HI all

I'm having my conservatory replaced, new frames and a solid insulated roof, so that it is actually useable. I was going to try and insulate the cavity of the existing dwarf walls (brick/block inner, stone outer), but having taken some sill off the gap is very variable (due to stone outer), electric cable for sockets and wall ties are present. This rules out slipping some solid insulation in from top. What's the current thinking about loose fill cavity (like Perlite) insulation. I read some horror stories about damp penetration. More work, but would I be better stripping existing P/B and refitting insulated P/B on inside (say Celotex 37.5mm Insulated Plasterboard PL4025 1.2m x 2.4m). Walls are 600mm, so perfect for 1/2 sheet.

Any advice appreciated.

 

[^woody^]

25mm of insulation is not a lot. 50mm would be more worthwhile

As the external leaf is loadbearing, you may be better off taking the inner leaf down and building an insulated timber stud wall.

 

[mellie_man]

"taking the inner leaf down and building an insulated timber stud wall" best idea but i'm not trying to create expense/work


how about the loose fill? easiest option.

 

[^woody^]

But you are already ripping frames and roof down!

Loose fill would be the least efficient, but Ok if the appropriate products are used and installed correctly to avoid damp issues. I doubt you can/should just pour a load of poly beads down.