Window straps air tightness insulated slabs on reveals

Carrickbeg

New build. Stepped inleaf back 62.5mm for insulated slab. Windows strapped from window to inner leaf at an angle as the windows are 62.5mm smaller than inner ope. Have insulation cavity closer flush with otter lear but again 62.5mm away from window. Can't firgure how to fill this void as window straps are in the way at an angle?
Any ideas out there?
Also,
Can't figure how insulated slab will work when window straps (and hopefully airtightness tape) are at an angle.

Bonzo Delaney

Bit of a balls up between the window manufacturer and the main contractor was there not a detail for this junction by the architect

Carrickbeg

Bonzo Delaney wrote: »

Bit of a balls up between the window manufacturer and the main contractor was there not a detail for this junction by the architect

No main contractor...direct labour...what's the correct way to do it? No detail on this from architect...seems stupid now...

Bonzo Delaney

Carrickbeg wrote: »

No main contractor...direct labour...what's the correct way to do it? No detail on this from architect...seems stupid now...

Windows are usually made to the size of the internal ope with extra wide stiles and head using insulated packing pieces then strapped back to solid block .
Sometimes there's a marine ply cavity closer fitted and willows fixed to this then Airtightness seal then insulated slab.
A picture would be needed to point you in the right direction.
I'm surprised the window rep didn't look for clarification on the window reveal and head detail

Carrickbeg

Oh Lord I understand what you mean...ill take a photo next time im out there...

BryanF

Carrickbeg wrote: »

No main contractor...direct labour..No detail on this from architect...seems stupid now...

Did you ask him for one?

Carrickbeg

BryanF wrote: »

Did you ask him for one?

No but I will Tuesday...

Bonzo Delaney

Carrickbeg wrote: »

No but I will Tuesday...

I don't mean to come across as a smart arse but its a few Tuesdays late for that now. Window junctions are an integral part of Airtightness.
Prob best solution now is to remove windows, add on a packer edge around if possible and refit to obtain the neatest and best possible outcome
It's hard to know whose at fault here depending on who was employed to oversee this particular section of the build .
Did the window rep even raise the issue of airtightness not that it's their responsibility but even for detail of measurement.

Carrickbeg

Not smart arse at all I'm glad of the advice. No window rep has been a bit of a nightmare to deal with. Will talk about anything except windows.

Gumbo

So have the windows been incorrectly measured?
If so, who measured them?

Carrickbeg

Windows were measured by window rep with measuring rod.
Windows the same size as outer ope but with this new idea of stepping back the inner leaf to allow for insulated slab the situation doesn't look ideal.

Bonzo Delaney

Carrickbeg wrote: »

Windows were measured by window rep with measuring rod.
Windows the same size as outer ope but with this new idea of stepping back the inner leaf to allow for insulated slab the situation doesn't look ideal.

It's not a new idea it's been applied at least 10 year now to allow for insulated slab.
Truth been told the stepped back internal reveal has been around donkeys years to accommodate weights on orignal sash windows the rep should really of at least mentioned it

Gumbo

Carrickbeg wrote: »

Windows were measured by window rep with measuring rod.
Windows the same size as outer ope but with this new idea of stepping back the inner leaf to allow for insulated slab the situation doesn't look ideal.

Ok then this sounds like a contractor issue. It has been altered since the window measuring. Now whether that’s the fault of the contractor, the designer or the client is for all 3 of you to sort out. The window guys done nothing wrong so far in my opinion based on the info supplied.

Bonzo Delaney wrote: »

It's not a new idea it's been applied at least 10 year now to allow for insulated slab.
Truth been told the stepped back internal reveal has been around donkeys years to accommodate weights on orignal sash windows the rep should really of at least mentioned it

In fairness to the window rep, there’s so many different detailing options, he is not there to question it or design it. He measured between the opes presented to him on the day.

Bullocks

Who is going to do the airtightness and drylining ?
I have slabbed them when they are left like that before . It's slow going but you could use tape and membrane to seal the window onto the reveal . Leave the membrane baggy enough to take the 62mm slab after .
The insulation on the back of the slab will probably need to be notched to fit around the straps that aren't giving 62mm clearance
To keep the slabs strong and square you can use a window framing bead on the frame for the slab to slip into and out at the corner where the wall slab meets the reveal slab a 50 mm piece of mf angle will pull the corner together ( you will need to notch the wall slab to let the reveal slab fit into it so the insulation isn't showing )
Your slabber shouldn't have much bother doing that but its slow and it would be better on day rate to its not rushed and care is taken with the airtight tape/membrane

The most thing I dont like about fitting the windows like that is that the straps aren't really at their strongest when they are nailed at an angle over that distance

Bonzo Delaney

kceire wrote: »

Ok then this sounds like a contractor issue. It has been altered since the window measuring. Now whether that’s the fault of the contractor, the designer or the client is for all 3 of you to sort out. The window guys done nothing wrong so far in my opinion based on the info supplied.



In fairness to the window rep, there’s so many different detailing options, he is not there to question it or design it. He measured between the opes presented to him on the day.

Self build as far as I can gather so 99% of the time the block work is already in place before windows are measured. I agree it is the contractors responsibility to make sure all details are complied with in the course of a build . In this instance this responsibility falls on the client to be up to speed with details as it's a self build .
While it's not the window reps responsibility I feel it should of been asked " whats the story here " to ensure a snug solid fit with the windows .
That's the problem with self builds . There always seems to be a attitude of " I'm alright now Jack it's the next lads problem now"

BryanF

Carrickbeg wrote: »

No main contractor...direct labour...what's the correct way to do it? No detail on this from architect...seems stupid now...

So you are the main contractor. You should have had DPC, cavity closer, air-tightness & insulation considered and prepared before the windows went in.

You went with a large Provincial brand, they don’t give a monkeys about how the detail outside of their window works.

you’ve a lot of frame verses glazing area, have you a lot of these small windows?

Carrickbeg

BryanF wrote: »

So you are the main contractor. You should have had DPC, cavity closer, air-tightness & insulation considered and prepared before the windows went in.

You went with a large Provincial brand, they don’t give a monkeys about how the detail outside of their window works.

you’ve a lot of frame verses glazing area, have you a lot of these small windows?

Yeah I realise that now...that's the smallest window in the house...I just took that for the photo purpose...thanks for the advice...

Carrickbeg

Bonzo Delaney wrote: »

Self build as far as I can gather so 99% of the time the block work is already in place before windows are measured. I agree it is the contractors responsibility to make sure all details are complied with in the course of a build . In this instance this responsibility falls on the client to be up to speed with details as it's a self build .
While it's not the window reps responsibility I feel it should of been asked " whats the story here " to ensure a snug solid fit with the windows .
That's the problem with self builds . There always seems to be a attitude of " I'm alright now Jack it's the next lads problem now"

Yeah im starting to see that now...

Wartburg

It´s a pitty that the most window installers here in Ireland do not have any knowledge about appropriate window fittings. There are plenty of fastening systems for windows available, to install windows with wide gaps around the frame in a secure way without struggling with the air tight layer afterwards. But almost all have to be screwed to the frame beforehand.

In your case I would probably use a rigid insulation board, bonded to the inner leaf and facing into your gap between the window and the cavity closer. I would cut pieces for in between your straps and cover around the straps afterwards by using expanding foam. Once the insulation is done, I would put a 12mm OSB into the reveal, fixed with a J-bead to the window frame and adjusting screws to the inner leaf, to have the provisional architrave installed squared. The front can be covered with OSB as well, when you install a batten to the block and the back of the OSB board in the reveal upfront. If this is done, you can use air tight paint, to make the OSB 100% air tight. You can apply a standard plasterboard to your OSB architrave afterwards and get it skimmed. It´s not the fastest and easiest solution, but it will definitely deliver a good insulation and air tight performance.
As a side note: Is there enough insulation between your block-on-flat and the cill at the bottom of your window opening?

Carrickbeg

They are 6inch blocks so ive 3inches of insulation between them and the cill.

Shauny2010

Get back onto the window installer, they could have modified the inside straps, or get them to make up a strap thats in an S shape to return in with the blockwork. I've seen the standard straight straps bent back to do this, but they tend to be a bit short. Its not a mission impossible job for them to do this. The alternative for you now is to knotch the insulated board where the straps are.

Wartburg

Shauny2010 wrote: »

Get back onto the window installer, they could have modified the inside straps, or get them to make up a strap thats in an S shape to return in with the blockwork. I've seen the standard straight straps bent back to do this, but they tend to be a bit short. Its not a mission impossible job for them to do this. The alternative for you now is to knotch the insulated board where the straps are.

The window installers would love to return to do what you suggested. On top I´m afraid that the existing straps are too short to bend them in an appropriate way, which means they probably have to install longer ones instead (in case they have them in stock).
Notching the insulated board is the last option, I would consider for my own house. Why shall I use an insulated board when I have to remove a huge area of its insulation? It could make more sense, to use a standard board and fill the gap between wall and board with suitable insulation material all-over. But you still have to create the air tight layer first.

Carrickbeg

Update

Reati

Carrickbeg wrote: »

Update

Seperate but important thing is watch those plaster protective sheets. The lads on site removed mine and made ****e of the windows by stratching the coating layer cleaning plaster off them.

Bullocks

Reati wrote: »

Seperate but important thing is watch those plaster protective sheets. The lads on site removed mine and made ****e of the windows by stratching the coating layer cleaning plaster off them.

Do you mean the plastic on the frames ? That should be taken off before plastering . There is no reason that they should get scraped either way during plastering

Reati

Bullocks wrote: »

Do you mean the plastic on the frames ? That should be taken off before plastering . There is no reason that they should get scraped either way during plastering

No, the plastic on the glass itself. The frames are fine. That's what happened in my place. They took the plastic off the frames but also took off the glass, plastered the place up and "cleaned" the windows, scratching the coating on the glass in the process.

Wartburg

To make it short:
A is the typicall situation when the installers of a particular window company left the site
B is the status, when someone took attention and passion to the insulation and preparation for following trades
C is the shape of the window after installing the internal air tight tape

The plaster can install the insulated slab thereafter, without any difficulties.

Carrickbeg

Wartburg wrote: »

To make it short:
A is the typicall situation when the installers of a particular window company left the site
B is the status, when someone took attention and passion to the insulation and preparation for following trades
C is the shape of the window after installing the internal air tight tape

The plaster can install the insulated slab thereafter, without any difficulties.

So can you make Picture A look like Picture B without taking out the window?

Carrickbeg

Wartburg wrote: »

To make it short:
A is the typicall situation when the installers of a particular window company left the site
B is the status, when someone took attention and passion to the insulation and preparation for following trades
C is the shape of the window after installing the internal air tight tape

The plaster can install the insulated slab thereafter, without any difficulties.

I'm guessing picture B is a different company?

Wartburg

Carrickbeg wrote: »

I'm guessing picture B is a different company?

I swear by god that all 3 photos were made at the same site, last summer in North Kerry. Creating progress as seen on picture B and C is part of my everyday work.

In theory, you can transform your windows the same way but your straps do look a bit too short to bend them into the right shape. You might should loose one and try it. And please do not use a nail gun or steel pins in case of a successful retrofit. A 7.5mm concrete screw, 30 or 40mm long will be the right way to fix the strap to the block.

Carrickbeg

Turned out alright in the end but would not advise it.

Wartburg

Looks good but the more interesting details are hidden behind your finish now.