I need to level out a screed. The high point is in the doorway, it
then dips rapidly by 5mm, and goes as low as 10mm below on parts of
the floor. Self levelling compound seems to go to 6mm, or if I add
sharp sand will go up to 15mm but not feather as well - which I need
at the doorway.

Am I missing an approach or is SLC with sand the way to go?

In article
,
Ben Blaukopf wrote:
I need to level out a screed. The high point is in the doorway, it
then dips rapidly by 5mm, and goes as low as 10mm below on parts of
the floor. Self levelling compound seems to go to 6mm, or if I add
sharp sand will go up to 15mm but not feather as well - which I need
at the doorway.

Am I missing an approach or is SLC with sand the way to go?

when I did this all those years ago, I did it in two stages. 1. the deep
bit with cement & sand and then, after a few days, self levelling over
everything.

--
From KT24

Using a RISC OS computer running v5.16

On Sep 7, 4:37*pm, charles wrote:
In article
,
* *Ben Blaukopf wrote:

I need to level out a screed. The high point is in the doorway, it
then dips rapidly by 5mm, and goes as low as 10mm below on parts of
the floor. Self levelling compound seems to go to 6mm, or if I add
sharp sand will go up to 15mm but not feather as well - which I need
at the doorway.
Am I missing an approach or is SLC with sand the way to go?

when I did this all those years ago, I did it in two stages. 1. the deep
bit with cement & sand and then, after a few days, self levelling over
everything.

What sort of mix would you use for cement/sand - and what is the
minimum thickness than it can reasonably be spread at?

Ben Blaukopf wrote:

I need to level out a screed. The high point is in the doorway, it
then dips rapidly by 5mm, and goes as low as 10mm below on parts of
the floor. Self levelling compound seems to go to 6mm, or if I add
sharp sand will go up to 15mm but not feather as well - which I need
at the doorway.

Am I missing an approach or is SLC with sand the way to go?


Stopgap 300:

It feathers well (metal plasterer's trowell). If in doubt put 10mm in the
deepest bit, leave 2 hours then do the whole lot. It bonds to itself well.

You'll have to check on F Ball's website - but IIRC it will go to 15mm
without filler or 20mm with granite chippings - but it could be 10/15mm


--
Tim Watts

Ben Blaukopf wrote:

On Sep 7, 4:37 pm, charles wrote:
In article
,
Ben Blaukopf wrote:

I need to level out a screed. The high point is in the doorway, it
then dips rapidly by 5mm, and goes as low as 10mm below on parts of
the floor. Self levelling compound seems to go to 6mm, or if I add
sharp sand will go up to 15mm but not feather as well - which I need
at the doorway.
Am I missing an approach or is SLC with sand the way to go?

when I did this all those years ago, I did it in two stages. 1. the deep
bit with cement & sand and then, after a few days, self levelling over
everything.

What sort of mix would you use for cement/sand - and what is the
minimum thickness than it can reasonably be spread at?

With SBR admix, 10mm min. That assumes you paint the floor with dilute SBR
and apply an SBR/cement slurry just before applying the screed.

--
Tim Watts