Can a cavity wall be 'full fill' with PUR type insulation?

[Watshot]

Hi chaps, in need of some more advice!

Building a small extension and the outer leaf is the local ironstone. This tends to come with two 'dressed' faces (front and bottom), and can be a bit hit and miss elsewhere.

I noticed a local builder using the same and the cavity was fully filled with what looked like Celotex type insulation or something along those lines. This enabled him to fill any voids and make a level bed for the next course with (what appeared to be) a sharp sand mix. As it 'rested' against the insulation the mix didn't fall down the cavity. This would give a good solid level for the next course. If I left a part empty cavity, a lot of the stone would need pointing and in-filling with pieces to make a level bed.

The builder wasn't there to ask, but it looked like a good idea. The only thing is I thought I might have read about a minimum gap of 25mm or something with Celotex. The builder may have been using a different product so I am not suggesting that he is wrong, just interested in any clarification.

If the insulation had foil both sides and was taped, i.e. a vapour control layer, would that be acceptable for 'full fill' or is it never acceptable?

Any feedback as always very much appreciated.

 

[^woody^]

You can't full-fill with any board insulation. IIRC, a minimum 25mm cavity is required

You can get some quilt insulation which has a foil face and this can be full filled and may look like celotex from a distance

 

[geraint]

Hi chaps, in need of some more advice!

Building a small extension and the outer leaf is the local ironstone. This tends to come with two 'dressed' faces (front and bottom), and can be a bit hit and miss elsewhere.

I noticed a local builder using the same and the cavity was fully filled with what looked like Celotex type insulation or something along those lines. This enabled him to fill any voids and make a level bed for the next course with (what appeared to be) a sharp sand mix. As it 'rested' against the insulation the mix didn't fall down the cavity. This would give a good solid level for the next course. If I left a part empty cavity, a lot of the stone would need pointing and in-filling with pieces to make a level bed.

The builder wasn't there to ask, but it looked like a good idea. The only thing is I thought I might have read about a minimum gap of 25mm or something with Celotex. The builder may have been using a different product so I am not suggesting that he is wrong, just interested in any clarification.

If the insulation had foil both sides and was taped, i.e. a vapour control layer, would that be acceptable for 'full fill' or is it never acceptable?

Any feedback as always very much appreciated.[/quo

you can full fill the cavity with fluff....

So what are you on about...

 

[Watshot]

you can full fill the cavity with fluff....

So what are you on about...

Even the resident Troll should be able to understand.........

Partial fill, full fill, various materials used in each, hence the question in the title alone, without the explanation given as a matter of courtesy........

The only cavity...........

filled with fluff............

appears to be.............

between your ears........

 

[stuart45]

Rigid full fill insulation is used a lot round here now with stonework to save building a backing wall. It's a closed cell board. Springvale platinum fullfill is one type you could use.

 

[Emeraude119]

As noted in another post on this Xtratherm CavityTherm is an (almost) full fill insulation system which incorporates a 5mm wide sheathing board on the front face. Therefore where 100mm Cavity =therm is specified you get 95mm of the PIR board + the 5mm sheathing.
It has a conductivity value much lower than that of the best conventional full fill insulations e.g. Drithetrm 32 or Isover HiCav 32, and is most often used where very low wall U-values are required, and /or where space is at a premium. They slso help developers / builders construct dwellings which comply with the Part L1/A 2010 and latest 2013 editions of the Approved Document, without the need to use Eco Bling such as solar thermal/pv panels
ground /air source heat pumps, windmills etc.
Springvale Ecobead platinum is the best of the blown bead cavity fill systems
but even this does not match the performance of Cavity Therm, resulting in wider walls for a given (very low) U-value.