Compriband on window replacements - how to finish paint coating?

[gravelld]

I want to specify Compriband (or equivalent) as part of replacing our windows.

 

The house is rendered. We will also be repairing the render and recoating with a flexible paint after the windows are installed.

 

So how should we paint up to the Compriband? Obviously, I don't want the paint to be touching the foam...

[Mr Punter]

Quite often I have seen this where they render a bit into the reveal, then paint the render, then window in, then Compriband between window and render.

 

I think the traditional way is to render up to the frames, where Compriband would not be the right solution.

[Simplysimon]

windows in, fit a slightly tapered filler around where the render will go to. render reveals, remove fillers and place compriband in the space, paint to compriband. 

[ProDave]

I must have done this different to everyone else (not unusual if I am left to work it out for myself)

 

The compriband is there to seal the side of the window frame to the (in my case) wood fibre cladding board.

 

But the compriband is well inboard and then the outside is rendered. The compriband is NOT left on view to be painted, it is some distance in behind the render.

[Pete]

9 hours ago, ProDave said:

I must have done this different to everyone else (not unusual if I am left to work it out for myself)

 

The compriband is there to seal the side of the window frame to the (in my case) wood fibre cladding board.

 

But the compriband is well inboard and then the outside is rendered. The compriband is NOT left on view to be painted, it is some distance in behind the render.

I have done the same @ProDave

[mvincentd]

9 hours ago, ProDave said:

the compriband is well inboard and then the outside is rendered. The compriband is NOT left on view to be painted, it is some distance in behind the render.

I have one window done with this approach, suggested by the window fitter and approved by idealcombi.

[gravelld]

Yeah - I realise in a rendered masonry new build we would probably have render beads on the windows themselves, so the render covers where the compriband is.

 

But here, the rendering already exists in the reveals and the replacement windows will be fitted in behind that render.

 

I just realised I've been  thinking about this in the wrong way. If the existing render finishes at the existing windows, should the compriband for the new windows be between the new window and masonry and therefore be invisible behind the existing render?

 

I suppose it depends how good a fit we get in the aperture with the new window, so long as the gap around the window is no more than the thickness of the reveal render the foam tape should be invisible?

[gravelld]

23 hours ago, Mr Punter said:

Quite often I have seen this where they render a bit into the reveal, then paint the render, then window in, then Compriband between window and render.

 

I think the traditional way is to render up to the frames, where Compriband would not be the right solution.

 

Thanks - bear in mind the house is already rendered - this is refurb.

[Mr Punter]

If you are fitting the windows up to the existing render I would just foam the gap between the masonry and the frame and run a small bead of sealant between the edge of the render and the frame on the outside.  Compriband not required.

[gravelld]

I don't really trust the sealant to last. If the sealant has gaps in, and the foam has gaps in (we know it's generally inelastic - even Flexifoam doesn't expand very well and keep adhesion) then that's more air movement through and around the window, giving a cooling effect.

 

I was hoping C would provide a longer term full seal of the gap.

 

Also, different topic because we're now talking about two 'sealants', what about water getting in behind the render to frame sealant?

[Mr Punter]

I think if you fully foam around the windows and have a quality sealant between the render and frame, plus an air seal internally from frame to reveal, there should not be an issue.

 

What type of windows are you having?

[craig]

Render stop bead.

[gravelld]

I can't use a render stop bead as I'm not re-rendering (unless I misunderstand).

 

Type of windows - alu clad 3G.

 

What render to window sealant products are recommended by those here? Don't want to take chances with this for obvious reasons.

[mvincentd]

https://www.illbruck.com/en_GB/products/product-finder/product/sp525-frame-and-facade-sealant-adhesive/

[Simplysimon]

remove existing window, make up a frame, put in place of window, render to the frame. remove the frame and install window with a bead of sealant on the outer edge of the render.

[gravelld]

So I think it's fair to say there's not the same level of scepticism about mastics between render and window as I retain!

[Simplysimon]

7 hours ago, gravelld said:

So I think it's fair to say there's not the same level of scepticism about mastics between render and window as I retain!

they have advanced, i can, unfortunately, remember when mastic came in 25kg tubs and we bedded sash and case windows in this new 'stuff'.