closing window cavitys before install

tred

Is there anypoint to this, if I am pumping the cavity and taping the windows?. Thoughts?

gears

I would say yes as the pumped insulation can "blow-out" through the air-tightness tape seal.

sydthebeat

tred wrote: »

Is there anypoint to this, if I am pumping the cavity and taping the windows?. Thoughts?

yes, definitely...

you need to hold the dpc tight to the outer leaf, and you also need to ensure the polystyrene beads dont flow out all over the place.

tred

sydthebeat wrote: »

yes, definitely...

you need to hold the dpc tight to the outer leaf, and you also need to ensure the polystyrene beads dont flow out all over the place.

must get at that so soon!

gears

Some of the bigger insulation companies have an integrated cavity closer, insulation and DPC in one which might be worth looking in to.

Topper74

Apologies for resurrecting this thread, but am at this stage now and want to know what is best tape to get so that plasterer won't have a problem with it (plaster not sticking to tape around window).

Also I have some old Fiber glass, I was going to tear this up and shove into any open cavities around windows, should this suffice?
Maybe break down some aeroboard and shove in there also.

6 inch cavity getting pumped btw...

Thx.

sydthebeat

Topper74 wrote: »

Apologies for resurrecting this thread, but am at this stage now and want to know what is best tape to get so that plasterer won't have a problem with it (plaster not sticking to tape around window).

Also I have some old Fiber glass, I was going to tear this up and shove into any open cavities around windows, should this suffice?
Maybe break down some aeroboard and shove in there also.

6 inch cavity getting pumped btw...

Thx.

check out sas's post here
see the second picture, thats how it should look after taping. theres no issue with plasterwork over this. A bond layer goes onto the exposed blockwork... the tape is adhered to the bond... and a finishing layer of bonding applied over.

why have you an open cavity around the window? fibreglass or 'broken down' aeroboard will do nothing useful here. I think we need pics.

Topper74

Ok I see what he did. I have a few gaps mostly to the sides of the windows. I'll try and get a pic or two and post asap.

Thx.

Topper74

Hi,

Just uploading pics on this as promised, Plasterer says he will take care of this by using expanding foam, but friend put in aeroboard and taped.

What do you guys think?

Thx.

sydthebeat

whats the storey with the full return block??? is there any insulation between the inner and outer at the jambs??

personally i dont like to see this detail being used anymore.

Topper74

No Idea Syd. I just let Blocker work away.

Just abit of aeroboard shoved it, getting cavity pumped.

What do you think I should do with this?

sydthebeat

Topper74 wrote: »

No Idea Syd. I just let Blocker work away.

Just abit of aeroboard shoved it, getting cavity pumped.

What do you think I should do with this?

well its too late now... do you have any professional inspecting the work?

is the return block a proper cast L block, or is it just an off cut of a standard block?

beyondpassive

Looks like a big cold bridge, also expandable foam isn't ideal around windows from an airtightness point of view, this is some of our latest thoughts on wide cavity closers and window placement. You just can't let block layers make it up as they go, another reason why we need mandatory building control.

Topper74

Just a cut-off standard block... have an engineer, he didn't say anything about it and I assume he has seen it.
I'm not going for airtight, just at this stage looking for best way to close it before plastering?

BryanF

Topper, listen to syd and Bpassive, this detail is out off date and not good practice for a new build, your engineer should be taking more of an interest:eek: As regards air-tightness contact some of the major air-tightness sales people and go on a day course on how to achieve air-tightness;) i believe one was ran in Mountrath recently, manufan16 one of the fellow self-builders attended

fclauson

Thought you had to do an air test now days

also check out the ACDs at http://www.environ.ie/en/Publications/DevelopmentandHousing/BuildingStandards/ for details on how to make the best detail at the windows

esox28

Topper74 wrote: »

Just a cut-off standard block... have an engineer, he didn't say anything about it and I assume he has seen it.
I'm not going for airtight, just at this stage looking for best way to close it before plastering?

hey topper, are you getting the outside walls scratch coated and then cozy boarded because maybe you could cozy up over the block gap??

martin46585

Does the openings have any dpc, as in picture 1 the cill seems to be much further back than the window, with no sign of dpc returned up the back of the cill, and no insulation to stop the c/bridge, might be worth a second look, as much harder to remedy later onn

BryanF

BryanF wrote: »

Topper, listen to syd and Bpassive, this detail is out off date and not good practice for a new build, your engineer should be taking more of an interest:eek: As regards air-tightness contact some of the major air-tightness sales people and go on a day course on how to achieve air-tightness;) i believe one was ran in Mountrath recently, manufan16 one of the fellow self-builders attended

Bryan who are doing these courses ? IS it worth doing. What does it cost ? Thanks

BryanF

Deleted User wrote: »

Bryan who are doing these courses ? IS it worth doing. What does it cost ? Thanks

definitely worth doing, as is getting some professional help;)

pm sent on the air-tightness