External Wall Instilation

[Bazile]

A few houses on our street have had the above applied to the walls .

How effective is this ?

[davebro3]

//8 disadvantages of external wall insulation types

Impermeability. One of the main disadvantages of external wall insulation boards is impermeability. ...

Size. ...

Cost. ...

Insulation issues. ...

Irritation to skin and respiratory system. ...

Weight. ...

Limited insulation value. ...

Environmental impact.//

I might be better to insulate the inside of the outer walls with insulating plasterboard. Reduces the size of the room a little though.

Builder will know.

[The Builder]

Unfortunately Dave, insulated plasterboard will add only minimal insulation (maybe 25mm.) I've treated exterior walls internally, but at least 50mm is needed to make a cost-effective difference. It's definitely disruptive. Skirting boards taken off; door linings have to be altered; also window sills; sockets etc.

Also, any partition walls tied into the exterior masonry will have to be treated as well because of the 'cold bridge.' i.e walls returning from a cold exterior.

100mm of board insulation applied extenally is very effective. It's relatively easy to install, and has the advantage of wrapping the entire fabric of the building. All done from a scaffold, with no internal disruption.

A 20th/21st century bungalow is ideal since the roof overhang can be anything up to 300mm, giving plenty of room for the insulation.  Victorian terrace is problematic as there is often no overhang at all. The roof eaves have to be extended. Even that's pretty simple compared to internal alterations though.

It all depends on the type of building you're dealing with.

Another thing is the finish. There are some modern finishings where the external insulation is covered in a board that takes a sprayed-on self-coloured coating which eliminates the need even for external rendering.

That's the gist of it anyway.  😎

[davebro3]

and - it might make the house more comfortable to live in but it will probably take years to recover the cost in reduced heating bills?

(A house I worked on had thick internal insulation applied but it was being taken back to brick anyway - I was only "ripping out".)

[Bazile]

thanks both 

It would be interesting to see before/after thermal image pictures