On 23/08/2019 20:31, Chris Green wrote:


As long as the fixings are sound I don't see any necessity for these.
Hanging the cupboards on screws will exert most force in shear and the
'pull out' force will be similar with or without the support at the
bottom. Admittedly our walls are very solid, I might go for something
extra on a stud wall, but in a stud wall I think I'd simply search for
the timber and fix directly or indirectly to that.

How? Particularly for "ordinary" carcases with a hardboard back. You
either fit a top batten with the hanger type fittings, or some sort of
intermediate batten attached to the carcase that you can screw through,
or a batten at the bottom that immediately ensures that all your units
are horizontal, and aligned vertically.


A well fixed steel screw will hold an incredible weight in shear. My
rule of thumb for steel's strength is 40 tons/sq in which gives a
shear strength of somewhere around a ton for a 5mm screw. The screw
will probably fall out first of course but I do always wonder why
people use great fat fixings for holding a few tens of kilograms.
Nearly all my fixings are 3.5mm or 4mm screws in yellow plugs and I
can assure you they *don't* fall out or break.


This is all true. However with a rendered random stone wall you will be
lucky to get any wall plug within half an inch vertically or
horizontally of where you actually want it, once you manage to get a
secure fixing.

I agree life is much easier in a modern house with decent brickwork or
blockwork.