What CAN'T you use for EWI projects? (low level / multi-level blending)

[Mr Gus]

As per title, what insulation board should you not use for EWI ? project is all ground floor, the majority not being higher than 8ft tall (mostly dwarf wall) ..it's that ever troublesome bay window, 3 sides of an oblong, with upvc sill to be extended out, would like to whack as much in till it makes no sense, so around 200ml of celotex.

Problem is, there are SO many variants of foam insulation board I get utterly lost in the process, not on about polystyrene in either of its forms looking to max out this aspect with as good a U value as possible, direction is mainly west facing, but with North & south rain driven ends.
I want to avoid rendering if at all possible & clad over with dark planking to blend more with the earth & green tones of the bushes in front to blend in as unobtrusive manner as possible (it faces the road) lest I have the council saying "never mind the climate" your red brick house looks too different to the others" ..if only they were as fussy about driveway brick "choices"

TBH plastic wrapped colour coated flat galv would please me immensely for no nonsense crofting / scandi weatherproofing approach.

cheers lads.

[Mr Gus]

K5 kingspan seems to be in favour here (a good site for detail)
https://ewistore.co.uk/kingspan-onto-brick/

https://ewistore.co.uk/installing-ewi-with-kingspan-k5/

(no association with the linked company, it merely serves as straightforward text) with an idea of component pricing from A-z.

[spread-tee]

We buy loads of stuff from the EWI store and find them nice folk to deal with, normally loads of stock and good delivery times too.. Applying EWI as shown on their guide is a pretty easy diy job if you have a basic feel for working these kinds of projects, with the possible exception of the final thin coat render. Perhaps get a spread to do that for you and you will end up with a professional looking job for a good price.
My only niggle would be the starter track at the bottom of the panels and the clip on drip section, it is fiddly in the extreme, fit the drip before sticking the panels or you will struggle.

Desp

PS, I find it much easier to use K-rend12 for the base coat, the EWI225 stuff is very sticky and hard to rule off with the derby to get it flat, it sticks all over the edge and tears up the surface you are trying to flatten, K-Rend cuts off cleanly and stays on the derby from where you can scrape it back into the bucket.

I think most rigid boards can be clad with shiplap, or UPVC panels to your choice, you might have to consider the fire regulations though if you are working within one Metre of the boundary, if so an intermediate board of "magply" will be the BC happy.

[Mr Gus]

Thanks Desp.

How thick can I go (the insulation board that is) ..am I ok to bond 2x 70mm K5 together if a starter strip will allow it.

Fiddly stuff would be left to the wfe (i'm brutally rough with that sort of thing, (like petting kittens in steinbecks of mice & men)

As it doesn't involve height i think the time has come to try some out this summer, esp as it will then set the scene for other things.

why is the plastic strip so much more costly than the aluminium strip? ..I can't see it myself.

[spread-tee]

The Ally starters are a single size quite flimsy bit of kit in various sizes only, you need to apply a separate drip and mesh to re-enforce the lower surface. The placcy ones are adjustable to suit various thicknesses of board and come as a complete unit with drip and mesh as one piece, much quicker to fix and use.

Desp

[robl]

re cladding:
Pretty much all insulation burns, which must be guarded against. You can use glasswool batts, then put whatever you like on it if you can fix it in place(difficult, don't do it). Or more conventional insulation + basecoat+mesh(it's fireproof) adhered to it - after that I expect (but don't know!) you could put whatever you like on it again, wood etc.
With EWI store(others must do this too?) you can get trained, then you're an approved installer, and can install as one of their bba certs. Maybe it's ok to stick wood on top of that (but ask them). I went on their training course, it was £60 and took a day inc travel, got a nice card with my face on it and some hands-on training as well as slideshow, Q&A, well worth it. 4 of us there training, 3 diy, one pro.
There are wood effect cement fibre boards I think. Prob still at a minimum need a basecoat+mesh though, otherwise you'd end up with a ventilated gap next to combustible insulation again.