Limited space window reveals

[pmcbythesea]

We are approaching internal insulation of external walls (1970s bungalow, upgrading thermal elements) and our BCO suggested we think about window reveals as potentially the weakest link in terms of insulation (walls are to have 25mm Celotex between timber battens on 18mm dense plaster on engineering brick, I know it's not much but there's no room for more). The reveals will allow a maximum of 15, maybe 20mm of Fermacell 10mm and insulation plus vapour barrier. It seems a no-brainer to me to go for 5mm (10mm where there is space) Aerogel Spacetherm, pricey though it is. BCO seems happy with this, he certainly didn't want us removing existing plaster which would destroy the integrity of the existing reveal. So Spacetherm glued to the reveal, vapour barrier on top, then Fermacell  fixed through plaster to internal brickwork. 

 

Any other possible options????

Edited August 24, 2016 by pmcbythesea
Forgot this - vacuum insulated panels were considered then rejected as (a) too expensive and (b) possible vacuum degradation