On Thu, 13 Feb 2020 15:32:15 +0000 (GMT), Dave Plowman (News) wrote:

But I'd like new worktops. Possibly something like Corian? I realise
this is likely a totally pro job. Is it strong enough to sit on top of
the carcasing or does it need additional support like ply or whatever
under it?

Worktops sit on the top of modern units, which are essentially just
open topped boxes, without any other support. A double width unit
probably has a bar across the midlle but that's more of a brace than
a worktop support.

Most of the 'pretty' ones I see now seem to have a chimney. Can those be
vented anywhere up that chimney - or only at the top?

I believe the chimney is just trim to hide bog standard vent tubing.

... but how about removing the mortar from them?

If it's a cement based tile adhesive you might have to resort to some
form of acidic descaler working up to brick acid. Try an overnight
soak, possibly with a bit of detergent as wetting agent.

--
Cheers
Dave.