Rigid wall insulation attention to detail

[goodbyegti]

Should I worry about gaps between boards like this? Personally I would be filling them and taping the boards together, but the day job prevents!

 

[nod]

Ideally they would be foil taped 

 

[Iceverge]

Rigid boards in cavity walls are almost never done correctly unfortunately 😔_.  

 

In an ideal world the internal wall leaf would be advanced first, then the boards would be stuck with foam, just like EWI, to the blocks. A continuous bead of foam around the perimeter of each to prevent thermal bypass and foam all the joints too and cavity tie penetrations. Finally the foam trimmed and all board joints taped and the external leaf completed. 

 

I have only seen one example of this ever. And that was someone's building his own house. 

 

 

I would forget about using them. Use a mineral wool batt instead for the remainder. Then some further internal insulation to make up the difference in U-Value. It'll be cheaper in materials and perform better. 

 

 

Edited April 5, 2023 by Iceverge

[goodbyegti]

Thanks both. Points noted for next time. I'll do my best to encourage better practice.