On 19/02/2021 16:19, Robin wrote:
On 19/02/2021 13:38, Scion wrote:
A friend had a low brick garden wall built with slabs on top for seating.
A couple of slabs came loose after very little use and it is evident that
none of them are fixed properly - a sharp tug will make them come off.

Builder is blaming friend, for having the temerity to sit on the seating
area. (Yes, he was told it was for seating.)

It doesn't help that the slabs are wider than the wall; the overhang
allows leverage forces to pull the slab up.

I'm happy to have a bash at fixing, my question is, what mix of cement/
sand/whatever should I use to obtain maximum "tensile strength"? Any prep
on the underside of the slabs? They are smooth-ish - think slate
texture -
but fairly thick.


Might help to know the height and width of the wall and the width of the
slabs.Â* If there's a really big overhang I wondered if it might be worth
thinking of (so as to speak) widening the wall to support the slabs.
Possibly galvanised steel angle screwed to the wall if they'd be low
enough to be hidden?

In the past I've solved this problem by drilling into the underside for
a couple of plugs, then inserted screws which stick out and provide a
key for the mortar to hang on to. Those were standard concrete coping
stones though so might not be applicable to the stuff you're working with.
John M