Granite chippings for deep self-smoothing screeds
Richard Hamer
fill a sloping area whose depth varies from 5mm to 20mm (ie. a bit too much
for self-levelling compound and a bit too little for true 3:1 screed).
The cheapo self-levelling compound I have opted for says to doa maximum
depth of 5mm, though this can be increased if small (<3mm) clean granite
chippings are added.
A couple of questions ...
(1) Anyone know where I can find such chippings? All the bags I have seen at
B&Q etc seem to be much bigger in size than this.
(2) If I can't find a good supply of chippings, is there anything wrong,
with the deepest parts, with just laying four 5mm layers, allowing plenty of
drying out time (eg. 1 week) between each layer?
Thanks,
Rich
Mike Amphlett
You may be able to get granite chippings from an aquarium
centre. But that might be an expensive option, it depends on how
much you need. As I work in the precast concrete industy I can
probably locate a source for you. Just let me know what part of
the country are you in.
Mike
* Sent from RemarQ http://www.remarq.com The Internet's Discussion Network *
The fastest and easiest way to search and participate in Usenet - Free!
Tony Polson
I would suggest that you lay a 3:1 screed with an SBR (styrene butadiene
rubber) admixture to a depth of 5-15mm in the low area, allow it to set
and dry out, then apply a 0-5mm self-levelling screed over the top.
If this is not acceptable, you can get 3mm granite chippings from a
builders' merchant. Ask for granite chippings as used in "granolithic
screeds". You may find the minimum quantity on the large side for your
needs; if so, shop around.
--
Tony Polson, North Yorkshire, UK
N Finnigan
news:rAPD4.6070$OC2.1...@news2-win.server.ntlworld.com...
> I am in the process of levelling out my uneven kitchen floor, and have to
> fill a sloping area whose depth varies from 5mm to 20mm (ie. a bit too much
> for self-levelling compound and a bit too little for true 3:1 screed).
If you can stand a slight height increase, or you can chip a bit
off the 5mm areas, then I'd put proper screed all over.
Otherwise, screed as much as possible (using a level from the
biggest bump), and then fill in with levelling compound.
> (2) If I can't find a good supply of chippings, is there anything wrong,
> with the deepest parts, with just laying four 5mm layers, allowing plenty of
> drying out time (eg. 1 week) between each layer?
I've tried 2 layers in places, but the SLC I used had very poor
adhesion between the layers
cormaic
<add...@foot.of.post> enriched all our lives with these words:
>A couple of questions ...
>(1) Anyone know where I can find such chippings? All the bags I have seen at
>B&Q etc seem to be much bigger in size than this.
You should be able to get it at most BMs - it's known in the
trade as grano dust - around 1.80 per 40kg bag, plus vat
--
cormaic - paving pages at http://www.tmac.clara.co.uk/paving/
Culcheth - Last Updated on Mar 17th 2000
cormaic CAN BE FOUND AT tmac DOT clara DOT co DOT uk
Richard Hamer
I'm in Ealing, London.
Rich
Email: DELETESTUFFIN...@ANDTHISgeocities.com
"Mike Amphlett" <mikeNO...@amphlett.screaming.net.invalid> wrote in
message news:180f889b...@usw-ex0106-047.remarq.com...
Richard Hamer
to ask about SBR, though I'll probs just use the SLC, and talked through the
problem with them. The trouble with granite chippings is getting them small
enough, so my plan is:
O Use self-levelling compound and granite chippings for the deeper portions
where the size of the chippings won't cause problems (perhaps 8mm+ deep)
O Use one layer of pure SLC for the thinner portions, up to 5mm
O And then apply a tacky PVA mixture to the whole surface (the pure bit and
the granite bit), and put down one more layer of pure SLC at a depth of
perhaps 1 - 3mm over the whole lot to bring it all together
Is this feasible - will the PVA improve the bonding strength between layers
sufficiently?
Thanks again for all the help, screeds are a nightmare to get information
about, none of the books I've seen cover them very well for these borderline
cases! I've decided to steer away from the SBR / 3:1 option cos I don't have
enough confidence in my weighing and mixing facilities here, I don't want to
risk a poor mix for such a thin screed.
By the way - the screed is for a kitchen floor which will be walked on,
under hard tiles (I think vinyl is too much of a risk here) but won't have
things like washing machines shaking it about.
Rich
john_h_schmitt
<n...@genie.co.uk> wrote:
[surface levelling compounds]
> I've tried 2 layers in places, but the SLC I used had very poor
>adhesion between the layers
This sounds like a laitence problem. It is very tempting to make
up such compounds overwet, and this tends to result in the free
lime and other fines rising to the top and forming a pale friable
layer, which acts as a release coating. If this happens, it can
be mechanically removed, the lower layer primes, and the
following layer applied.
John Schmitt
john_h_schmitt
"Richard Hamer" <add...@foot.of.post> wrote:
>Is this feasible - will the PVA improve the bonding strength
between layers
>sufficiently?
As long as laitence is avoided/removed the compound, if a
water-mix already contains redispersible PVA resin, so It should
stick well. If a latex or acrylic it also contains something
which will make it stick well, as anyone who let it set on their
tools will tell you. Certainly, the PVA will not cause a problem
with water mix, but might antagonise latex and acrylic compounds
if it is still wet. If dry there should be no compatibility
problems.
> I've decided to steer away from the SBR / 3:1 option cos
I don't have
>enough confidence in my weighing and mixing facilities here, I
don't want to
>risk a poor mix for such a thin screed.
Most mortars are gauged by volume, and exact ratio is not too
critical, as long as the mixture is not over rich in cement. SBR
(styrene butadiene rubber - a synthetic latex) will retain
moisture in even quite thin layers, so that the screed will cure
and adhere well.
John Schmitt
>By the way - the screed is for a kitchen floor which will be
walked on,
>under hard tiles (I think vinyl is too much of a risk here) but
won't have
>things like washing machines shaking it about.
>
>Rich
>
>
>
>