On 03/12/15 09:27, Stephen wrote:
Hello,

I read this on the paving expert web site:

"There is often a temptation for installers to use either a mortar
with a higher cement content, say a 3:1 mix in place of a 6:1 mix, to
use PVA as an alleged bonding agent, or to combine a cement-rich
mortar with PVA and hope for the best. Adding cement to a mortar does
not, in very general terms, improve its adhesive properties, and PVA,
being water-soluble, is a sort-term fix that will eventually be washed
away."

It goes on to recommend using SBR. My question is, I have always
followed the instructions on the cement bag, which says to use 5:1 for
general use or 3:1 for a strong mix. The advice above, appears to
contradict that, saying a stronger mix will not actually be stronger.

To put this into context, the paragraph is talking about cementing
pavers as the treads of garden steps. I did use SBR as the web site
recommended, and they do seem rock solid but I was not using a 6:1
mix. Could I have saved cement by doing so? What ratios do you use?

Thanks,
Stephen.


The 2 ways I improve bonding a

1) Wet the bricks first and use a mix that in itself is right (ie not "
a bit wetter to allow for brick suckage");

2) If it's a fiddly brick - top corner for example, the ones that always
seem to fall off when "professionals" do them: Wet the brick and paint
with a cement/water slurry (honey thickness). I might switch up to a 3:1
mix too for that. My bricks do not come apart, ever... Not that's I've
done a lot - few repairs, couple of brickwork gulley drains.

SBR would work too...