On 18/03/2019 08:13, alan_m wrote:
On 17/03/2019 14:24, Mathew Newton wrote:
On Sunday, 17 March 2019 14:12:04 UTC, JimKÂ* wrote:

If you are plastering walls around the opening then you can apply
plaster direct to the lintel just press the initial bonding coat into
the gaps to maximise adhesion.
I wouldn't do that as if the rest of the ext walls are insulated
Â* the reveals will become the coldest place = condensation, mould
Â* etc.

Yes, I am keen to ensure there is at least some insulation around the
reveals (although the door frame width means there won't be all that
much).

I also don't think plasterboard adhesive necessarily sticks well
Â* to the insulation of insulated plasterboards.
Depends what the insulation is faced with ? Paper? Foil? Foam?

I'll be making my own plasterboard+insulation sandwich and so it'll be
foil backed. I too had read that dot-and-dab adhesive doesn't stick
well to it, but it seems that most 'tube' adhesives do.


Use one of the foam adhesives which will not only stick to the surface
of the lintel but expand into the slots in the lintel.

example
https://www.screwfix.com/p/dow-insta...de-750ml/72793


similar available in a container with integral "gun/nozzel"

I've recent had some work done on my house and this type of adhesive was
used to bond some wood to a sandstone type surface prior to plasterboard
being screwed to the wood and then skimmed.Â* Excess foam was easily
removed with a knife albiet there wasn't much excess because it was alow
expansion foam.


Is this cladding to increase the fire rating?
If it is then foam is not a good idea.