On Monday, March 16, 2015 at 11:42:18 AM UTC, Tim Watts wrote:
On 16/03/15 07:28, stuart noble wrote:
On 15/03/2015 10:31, JimK wrote:
/Tim Watts
- show quoted text -

SBR would be an extreme option. /q

+1

Jim K


What is never mentioned is that SBR can't easily be incorporated into a
s/c mortar. Unlike pva, it leeches out of the mix, and does its own
thing as the mortar dries, to the point where you might as well apply it
to the substrate instead.

Having used it a little, I would disagree. Yes, it does tend to come
out. The secret is (as I was doing with floor screed) is to have a very
dry mix - the SBR acts as a plasticiser so it feels "wetter" than it is
anyway. Anyway, there's more than enough stays in the mix to turn it
into iron. I tried chiseling a high spot off my screed a couple of weeks
later and a scutch comb on an SDS was barely touching it.

Screed mix would be a good bed for the shower tray.

I've got a screed section with SBR and glass fibres ! I used it over a joint in the underlying slab which was unlikely to move, but better safe than sorry.
I made an inch thick "concrete" slab with the left overs. It is a very interesting object !
Simon.