Possibly a bonkers idea - cavity wall insulation

[AGT]

I like option 1, I know I know, but I like the fact that you can improve a rooms thermal performance one room at a time, insulated plasterboard, glue gunned onto existing wall can be done relatively quickly, same with internal finishing etc taping/plastering.

[Joeboy]

I like option 1, I know I know, but I like the fact that you can improve a rooms thermal performance one room at a time, insulated plasterboard, glue gunned onto existing wall can be done relatively quickly, same with internal finishing etc taping/plastering.

Is that really a thing, glue gunned thermal.plasterboard? I had no clue, decent R value per sheet is it? I've got an internal gable wall you know...




The whole stairwell is about 26 degs the now. Although there is 0.3deg difference between the NE facing gable and either internal wall. That would be about 12sq mtrs further insulated. Sorry OP, no hijack intended.

[AGT]

Other makes available

https://www.screwfix.com/p/soudal-geniu ... 50ml/812cf#

[AGT]

https://www.kingspan.com/gb/en/products ... sterboard/

Insulted plasterboard, various thicknesses to suit every install

[Joeboy]

Thank you mate, that's just went on my Winter list.

[cojmh]

Other makes available

https://www.screwfix.com/p/soudal-geniu ... 50ml/812cf#

I had never heard of this either and it looks pretty good for making a job quicker and easier. I wonder if you use it to put plasterboard up to the ceiling (obviously supported till the product has dried!)

[cojmh]

I like option 1, I know I know, but I like the fact that you can improve a rooms thermal performance one room at a time, insulated plasterboard, glue gunned onto existing wall can be done relatively quickly, same with internal finishing etc taping/plastering.

I accept it is faster and cheaper, but the only problem I see with this approach is the areas that you cannot get to such as the voids between floors, under floors (when suspended) and other hard to reach places.

with options 2 and 3 (vastly more expensive) if covers everything

although with a staircase (as long as you can get to under the stairs) it should do well.

[AGT]

I imagine ceilings would be better fixed with screws, counter batten existing ceiling to get decent fixings with a timber, leave existing ceiling in place

Long screws are available so that makes more sense

[Joeboy]

OP,

Any use?
https://www.kingspan.com/ie/en/knowledg ... -solution/

Sorry, its a floor system, the photo threw me!

This seems like a reasonable priced solution but the R value is nowhere near OP's req's.

https://www.insulationsuperstore.co.uk/ ... -30mm.html

Could this be put up on the inside and the outside covered in a thinner layer EWI to more preserve the side access? Internal vapor movement being the big one , I didn't dig into it to see.

[cojmh]

Thanks for the suggestions JB.

The floor solution might be useful for the underfloor heating - I will investigate, but unfortunately not for the walls

With respect to the wall insulation my understanding is that EPS will never achieve the the same U value for the same thickness as PIR and the only solutions that seem to exceed PIR was the aerogel but it is not as significant a space saving once we start getting into the smaller u-values.

But thank you for the ideas.

As an update the structural engineer has come back and said it is technically possible but we will have to do the wall in sections and it will be important how we support things in the mean time (belts and braces approach). Next step is looking at the foundations.