insulated cavity closers??

ollie30

can any one advise me if it's worth while using these cavity closers around window and door openings.there's one called thermabate and i think rockwool make one.do they cut out the thermal bridge any better than the builder cutting insulation strips and blocks to close the cavity.do people use or bother with them for one off building?also has any one used or know about the perinsul sl block www.foamglas.co.uk ,again is it worth paying for?

De_man

ollie30 wrote:

do they cut out the thermal bridge any better than the builder cutting insulation strips and blocks to close the cavity.

Took me a week (on/off) to seal all the windows and doors using insulation strips of "platinum".. when completed i still had to use some expanding foam WHAT A NIGHTMARE of a job to do properly!!

if you reckon those products will work for you go for it...anything but the insulation strips...never again

Mellor

Its better to find a compressable insulation to seal to opes, not as much need to cutting, and no expanding foam in a can

ollie30

De_man wrote:

Took me a week (on/off) to seal all the windows and doors using insulation strips of "platinum"..
cheers de man, i noticed you mentioned platinum was it the aerobord 150mm?if so how did you find it ,does it sit tight against the inner leaf as snug as they suggest without a retaining disc though i think it has a retainer on the wall tie.
mellor ,what type of insulation would you class as compressable that would'nt loose any insulation value?
ollie

De_man

ollie30 wrote:

De_man wrote:

Took me a week (on/off) to seal all the windows and doors using insulation strips of "platinum"..
cheers de man, i noticed you mentioned platinum was it the aerobord 150mm?if so how did you find it ,does it sit tight against the inner leaf as snug as they suggest without a retaining disc though i think it has a retainer on the wall tie.

ollie

Hi Ollie, this job is going to do your head in!!!!! it's kinda hard to explain..
I used 75mm "platinum" in the cavity cut into approx 150mm widths using my electric saw it was easier to ensure the accuracy of the cuts
i then measured the gap between the two L blocks (between the internal and external cavity)
typically 40-50mm this figure varied a little (where the lads didn't use L blocks
then subtracted say 2-3mm and pushed the insulation in to meet the insulation that was already in the cavity, sometimes i had to use the hammer:D

Making sure that the DPC for the windows etc was resting on the inside of the external cavity and allowing some DPC for the plasterer when doing the windows!! i then used a hand saw to trim it down to ensure it was flush with the outside of the L blocks. on some places i had to use a bit of expanding foam....

For the cills, i cut the aeroboard into 150mm widths, measured the cills
then measured the gap between the cill and block (typically 15-20mm)
i then cut the lengths of aeroboard into these widths and ensured there wasn't any gaps between the back of the cill and the block, again where i couldn't fix properly i used expanding foam...saying that the window installers
thought i was a lunatic cause they said they very rarely saw this level of
work done on a house...:rolleyes: makes me wonder what would have happened if i got someone to do it!!! i saw another job where this was done and the quality of work leaves a lot to be desired:mad:

I back filled the cills (using a strong concrete mix with sealant)
before the windows were installed, whether this is right
or not is questionable, cause the lads when installing the windows put
brackets on the area where i backfilled so when i install the window boards
i'll have to get the router to sort that problem.

In my defence i'm not a builder, i wouldn't have the skill to get the back filling correctly done after the windows were installed - i'd only make a complete mess, doing it this way at least i know everything is correct

best of luck with it, it really doesn't require that much skill only plenty of patience one word of advice have plenty of bags around for the off cuts
as these go everywhere

hope this helps

De_man

ollie30 wrote:

De_man wrote:

does it sit tight against the inner leaf as snug as they suggest without a retaining disc though i think it has a retainer on the wall tie.

Sorry didn't answer your question, no problem it fits snug no disk required

ollie30

thanks for that,will take great heed

Salmon

Hey De Man,

Any chance of a few pics of this installation? At the same stage myself and am contemplating whether or not I should close off the cavity before putting in the windows! Anyone have any data as to the effect this has on the insulation values of the windows?

ardara1

Salmon wrote:

Hey De Man,

Any chance of a few pics of this installation? At the same stage myself and am contemplating whether or not I should close off the cavity before putting in the windows! Anyone have any data as to the effect this has on the insulation values of the windows?

These areas where the insulation is broken must be measured now under the new regulations - there are a set standard details published by Homebond "Right on site" manual which are MINIMUM standards - theres also as set of accredited details published in the Planning Portal websitein the UK that our regs refer to.

Once you have a wall well insulated these junction become more critical - heatloss isn't thru the main body of the wall -- it's theu the bad jointing - up to 30% of fabric loss in a well insulated building. Look at it like a sponge wrapped in polythene with top and bottom exposed - the water won't go thru the polythene - but sucked out thru the exposed bits BIG TIME

arghh

I not a builder but after using about 10 cans of expanadble foam, its horrible to work with, hard to control over what your doing. I would put rigid insulation around the windows before they would be installed. It would be a better job all around.

Salmon

Gonna have a go at putting in the rigid insulation this weekend! Will post up some Pics on monday, looks like its goin to be a nice weekend to get a few bits and pieces done! I guess I should keep the DPC towards the outside of the external block. So you have external block-DPC-Insulation-Internal Block. Does this make sence. Probably best tow do a couple and post up some pics on mon!!! Have a good weekend all!!

De_man

Salmon wrote:

I guess I should keep the DPC towards the outside of the external block. So you have external block-DPC-Insulation-Internal Block.

hi ya salmon, your catching me:D

100% correct, my "system" was...i did the sides first, then did the top
part (lentil) make sure the dpc is available for the plasterer (1/2" or so),
(if necessary you may have to add to it)

Enjoy