Is celotex a better alternative to foam spraying loft?

[fitzykev]

I heard that spraying a loft with foam can cause properties to be unmortageable although I'm not sure how much of that I believe. Is celotex a good alternative and is it expensive?

 

[Why Not Indeed]

I am sure it's technically possible to spray-insulate a roof with foam in such a way that doesn't leave the timbers vulnerable to rot, but resulting increase in labour costs would mean that it would be not much more work to use PIR foam boards.
You can save money by using seconds. Only you can say if it's expensive or not.

 

[Tigercubrider]

Celotex is removable.
sprayed on foam isn’t

celotex can be set up to ventilate
sprayed on foam can’t

 

[fitzykev]

Spray foam to me sounds like a potential disaster if water or condensation was to get into the other side it could be a nightmare

 

[StephenStephen]

Are you converting the loft to a living space?

 

[fitzykev]

No just want to get an extra layer of insulation in. It's a two bedroom bungalow. Hopefully easy enough to keep cosy

 

[Tigercubrider]

A DIY loft insulation is bound to be cheaper

 

[fitzykev]

Plus I like the sound of celotex over spray foam. I am just hoping the roofspace is not a shared one

 

[Deleted member 174758]

Spray foam to me sounds like a potential disaster if water or condensation was to get into the other side it could be a nightmare

It is a potential disaster because it stops transpiration of water in the rafters and roof timbers leading to accelerated rot

 

[HERTS P&D]

400mm of loft insulation is what you need on the loft floor. Your loft needs to be breezy so the timbers stay nice and healthy.

Andy

 

[Mr Chibs]

Step-away-from-the-spray-foam

 

[fitzykev]

Yes thats why you leave a slight gap between the Celotex and the roof underlay

 

[Lower]

Do you want to keep the heat in the rooms below the loft or keep the loft space warm?

if you want to keep the rooms warm, insulate above their ceilings, not between the roof joists.

 

[fitzykev]

I am insulating above the ceiling also. I want the roof joists done for that extra layer

 

[HERTS P&D]

Are you converting the loft into a room?

Andy