Best / most cost effective window reveal insulation.

[Dodgyrog]

Woody previously helpfully advised me on internal insulation cavity wall being upgraded in an internal garage conversion - in someone else's thread.

I've cracked on and put 50mm insulated plasterboard on the wall itself, the new double glazed window is in, DPC'd at the frame etc.

Have put insulated cavity closer in so it's now just finishing the reveals - there's 35mm of frame exposed (reveal to bead). Have looked around online but wondering what best available method is - looks to be a few so called reveal insulation systems....

It's only one window to do 700 x 1300 so want to buy minimum materials.

TA

 

[Swwils]

The absolute best would be a aerogel style board but it can be tricky to attach. If you only have 50mm insulated plasterboard elsewhere a 20mm + 12.5mm insulated board will be more than enough - especially if your windows are correctly over the cavity closers.

 

[^woody^]

What's the wall construction make up?

You could do without, or just a nominal layer of 5-10mm polystyrene or suchlike

 

[Dodgyrog]

What's the wall construction make up?

You could do without, or just a nominal layer of 5-10mm polystyrene or suchlike

External render, brick, blown in insulated cavity, clinker block, 1/2" plaster - now with treated batten and 50mm thermal backed PB.

The easiest / most available option for the reveals would be polystyene as you say - but it's more how to attach it? There's decent batten on the inner edge as part of the main wall set up but how to fix to the edge near the window? Been googling and couldn't really see an obvious answer - maybe I'm over thinking it - I couldn't find anything apparently suitable for sticking polystyrene and if mech fixings then would need to be very thin batten I guess, and there's a slim bit of brick left between rear of window and cavity.... I'm def overthinking it maybe !... I'm an engineer and piggin' well overthink everything

 

[cdbe]

Personally I'd just plasterboard it, your windows will look strange without a reasonable amount of frame showing at the edges.

 

[Dodgyrog]

Personally I'd just plasterboard it, your windows will look strange without a reasonable amount of frame showing at the edges.

Yep I'm coming to that conclusion in that just plasterboard will allow a slightly thicker batten to be there to fix to - with the cavity closer in that area then Im assuming adhesive is not the way to go.

There's varying thicknesses of polystyrene readily available which I could always fit between the battens and it gets trapped in by the plasterboard - if I really needed to get some insulation in there - but I wouldn't know if that will cause other issues ie is it better to have insulation or an air gap between the plasterboard and the reveal that is mainly made up of plastic cavity closer?......told you I over think things lol.

 

[cdbe]

I'm new to cavity closers (used to be brick and a strip of dpc) but here's mine, pretty well wedged in, unless I'm mistaken, the usual method is just to dab on plasterboard:

Wooden battens aren't great for thermal insulation so I'd try to avoid if possible.

 

[^woody^]

The easiest / most available option for the reveals would be polystyene as you say - but it's more how to attach it?

If you are fixing to battens, then it not an issue - you fit the insulation behind, between or on top of the battens.

But there would not be a problem if you just fitted the plasterboard and no insulation, as the cavity closer is dealing with any local cold bridging.

 

[Dodgyrog]

If you are fixing to battens, then it not an issue - you fit the insulation behind, between or on top of the battens.

But there would not be a problem if you just fitted the plasterboard and no insulation, as the cavity closer is dealing with any local cold bridging.

Cheers.

I'll plonk whatever thickness I can between the battens - then along with the 50mm insulated main walls, heavily insulated floor and partition semi external wall I can happily say to BC I put in more than reasonable effort to improve insulation of a very short stretch of external wall which represents a tiny fraction of the perimeter of our bungalow, which is in otherwise good nick, warm, new double glazing etc.
Thanks again.

 

[oldbutnotdead]

You could use Marmox board if you're really worried - it's designed for wet rooms but is an insulator & also waterproof. Various thicknesses from 6mm up available. I'd agree with whoever said window would look odd without a bit of frame between wall and glass, plus be a sod to get the beads out if you ever needed new glass