Insulation Works - Shall I knock down my house?

[JP_]

There is another option. Solar panels and reversible air conditioning.

Yeah, looked into solar panels, made an enquiry then got loads of annoying sales calls, and that put me off!

Not got money to install them now, and don't want to get tied into any schemes.

 

[mrrusty]

"walls with 50mm kingspan"

Beware condensation with internal insulation. You don't want the dewpoint in the wall. Did you work it out?

This is an interesting conversation - and one I had with the LA BC guy when we planned to significantly internally insulated our edwardian. We/he decided that interstitial condensation was not a risk and that it was better to insulate than not. What was a factor in this decision was the well-ventilated cavity which should evaporate any condensation that occurred in the inner brick skin. So far (2 years) everything is absolutely fine.

I am sure that with 60mm PIR insulation there is a theoretical risk of interstitial condensation. I am not sure I would do it if the cavity was unventilated - e.g. filled with cavity wall insulation.

 

[JP_]

My house is solid walls, which I guess is like a single skin with an endless cavity on the other side ...

 

[mrrusty]

My house is solid walls, which I guess is like a single skin with an endless cavity on the other side ...

My own opinion is that if it is unsealed brick and can breathe it would probably be OK, but if it was sealed/rendered and any condensation built up in the fabric of the wall and couldn't easily evaporate, then perhaps not. This seems to be a huge subject that you can find a wide variety of opinions on - many contradictory. Probably because there are so many variables in building construction, so take my view as just another opinion....and do what you think is best.

 

[JP_]

Thanks. Inside is already insulated, and outside falling apart before the insulation was put on, so I'll take my chances!
But as I said, the insulation was installed with plenty of insulated foil tape, the boards are foil backed both sides, and the walls were cold in winter anyway, with condensation on the inside causing mould, so presumably also condensation within. So, the current state must be drier, as well as warmer and healthier inside the house.