Spray Foam Insulation with PIV

[Neill]

Hello,

 

I am considering having spray foam insulation applied to the roof space of our house having seen it done to a neighbours house recently. I had the supplier round for a survey and I mentioned to him that I was intending to install an PIV system (drimaster or the like). He said that it would not work as the spray foam essentially makes the roof space ‘air tight’ and would prevent fresh, outside air entering the roof space which in turn would stop the PIV from working. 
 

Any thoughts/ experiences of this? I am keen on the PIV as we installed one in our last renovation project and never experienced any damp or condensation (a personal bugbear of mine) which I found impressive. I also like the look of the spray insulation. Is there an out of the box solution or work around? 
 

Any info would be appreciated.

 

Thanks 

 

 

[Declan52]

Install a mhrv system. The amount of vents will be limited but depending on your house layout might still work.

[Neill]

Thanks for the reply. MHRV is a no go as the house won’t be airtight enough and it has an awkward shape that wouldn’t lend itself to retrofitting ducts.