Internal insulation for block cavity walls

[Roger440]

Thanks for the explanation.

 

I see 2 issues preventing me here. One, i wouldnt have the first clue about how to manage or deal with the electronic/IT side of all that.. But probably more importantly, if it subsequently showed a problem, that would mean major rework to deal with it.

 

Thats not something i can do. If i do something it has to be right first time. 

 

Paying for WUFI is yet more money not spent on actual upgrades. Its not about justfying it, you still have to have it. If it just ended at that report it wouldnt be so bad. But it doesnt.

 

As i suspected, and you essentially confirm using a ubakus model isnt without risk.

 

Which leaves doing nothing as the only "risk free" option. Which, im not keen on as the extension is really quite poor thermally, not helped by fronting into the prevailing wind. The old stone part of the house is far better in that regard.

 

As regard joist ends, that something ive yet to establish what has been done. If its through to the cavity, that probably the end of cavity fill ideas.

[Mike]

12 hours ago, Roger440 said:

i wouldnt have the first clue about how to manage or deal with the electronic/IT side of all that.. But probably more importantly, if it subsequently showed a problem, that would mean major rework to deal with it.

Yes, if you're not into electronics and don't know someone who is, then monitoring is out - but if it did show a problem then it would be better to resolve it than to wait for structural damage to set in. However I'm not suggesting using it as a way of pushing the boundaries, only for curiosity or reassurance. I'm doing it for both reasons - WUFI suggests that my ceiling will be OK but, as it's a highly unusual situation and I still have a few reservations with WUFI, I want to validate it.

 

12 hours ago, Roger440 said:

Which leaves doing nothing as the only "risk free" option. Which, im not keen on as the extension is really quite poor thermally

Then option 1 on my list is probably going to suit you best, if you still want to consider IWI. That is, go to the technical department of Pro Clima or the like and ask if they'll do an evaluation for you.

 

12 hours ago, Roger440 said:

not helped by fronting into the prevailing wind

If you add your proposed rain screen (and it's not airtight), the chances are it will add to the drying capacity of the wall and be in your favour. Although if you can add a rain screen, maybe you can add external wall insulation, which is going to be preferable.

 

12 hours ago, Roger440 said:

As regard joist ends, that something ive yet to establish what has been done. If its through to the cavity, that probably the end of cavity fill ideas

There are many properties with cavity fill and joists embedded in the wall without problems so, if you forget the IWI and just fill the cavity, then you should be fine. However make sure that the rooms are adequately ventilated and you make the wall airtight, particularly at the joist-wall junction. At ground floor level, add plenty of ventilation to the sub-floor void (if that isn't already the case) and insulate the floor well - there are other threads on here about both.

 

Edited 9 hours ago by Mike