Options for external rigid board insulation to go under render

[Adsibob]

We have removed the pebbledash from a 1930s semi and had planned on installing 40mm of external rigid board insulation onto the brickwork which we have exposed, and then rendering over that.

Kingspan K5 is a phenolic core which is faced on both sides with glass tissue (more details here). Problem is it comes in 20mm and 50mm, but not 40mm. 40mm is already making things a bit tight in terms of keeping the original features of the house, but we can just about make it work. 50mm would be too much though.

 

Can anybody recommend something similar to K5 that comes in a 40mm thickness? I don't think PIR is an option because that tends to be foil faced making rendering over it not really an option.

 

We could use two lots of 20mm thick Kingspan and just fasten the fixings of the outer layer through the inner layer and then onto the underlying wall, but it is effectively twice as much labour, so I rather not do that. 

[PeterW]

K5 is available in 40mm

 

https://www.insulationshop.co/40mm_kooltherm_k5_external_wall_kingspan_1200mm_x_400mm.html

 

 

[Adsibob]

1 hour ago, PeterW said:

K5 is available in 40mm

 

https://www.insulationshop.co/40mm_kooltherm_k5_external_wall_kingspan_1200mm_x_400mm.html

 

 

@PeterW you are a genius, thank you. Not sure why that size isn't available on the sites I was looking at.