cavity closing ' is it needed'

esox28

I am thinking of my options to close a 150mm cavity wall around the wondows and doors, the insulation im using will full fill the cavity, with an 'aerobord 140mm' sales guy just says to close with plaster board and seal with air thghtness tapes. I have located some Polycarbonate Perspex Clear Sheets that I can cut and nail around the openings and install the plaster board on top.

is putting the poly sheet a step too far?

scuggels

esox28 wrote: »

I am thinking of my options to close a 150mm cavity wall around the wondows and doors, the insulation im using will full fill the cavity, with an 'aerobord 140mm' sales guy just says to close with plaster board and seal with air thghtness tapes. I have located some Polycarbonate Perspex Clear Sheets that I can cut and nail around the openings and install the plaster board on top.

is putting the poly sheet a step too far?

Can your block layer not return the reveal with a block and brick fully closed off then

fealeranger

I am too looking at this issue. I have a 300mm cavity and trying to figure out how to close it without making a cold bridge by returning blocks is proving to be a challenge especially when considering structural integrity in the process. There is a wide cavity closer available but the sales guy said I had to buy the whole pallet of it when I only needed half the pallet load:eek:. 150mm cavity should not be too bad as I have seen various insulation supplier cavity closers for this size cavity during my research. I am going to go with closing the window cavity with thick insulation from the floor stuffed into the cavity and plaster board over it but for the doors I am going to take the hit for a cold bridge and return the block unless there is someone here that can suggest another alternative;). I don't know about the poly sheet but look up some of the well known insulation brands and yo will see the cavity closers they showed me. Pm me if you are stuck and I will give you what I have gathered so far.

esox28

I see what you are doing with the thick insulation to close the cavity, its a low cost answer to the issue. yea ive seen the insulation companies cavity closer board, way too expensive and dosent need to be so high-tech also ive heard that the insulation has a tendancey to seperate from the plastic board at times.

from what you said i think i will close the cavity with a 25mm pir insualtion board because my cavity is already full with aeroboard insulation.

sydthebeat

esox28 wrote: »

I see what you are doing with the thick insulation to close the cavity, its a low cost answer to the issue. yea ive seen the insulation companies cavity closer board, way too expensive and dosent need to be so high-tech also ive heard that the insulation has a tendancey to seperate from the plastic board at times.

from what you said i think i will close the cavity with a 25mm pir insualtion board because my cavity is already full with aeroboard insulation.

25mm wouldnt have much 'purchase' from a friction fitting point of view.
If you can get 100mm easy id use that instead.

esox28

yes completely right, but having talked to builder he says with the full fill cavity insulation he just cuts flush to window/door reveal.