Ladybodger wrote:

Thanks so much Wig, that's really helpful - now I can't wait for the
nice weather so I can get cracking! I do usually buy 'just add water
cement' because I never knew the mix, and of what to mix, and if it
was
different for different jobs - so you've helped me very much. Thank
you.

A 3' retaining wall is quite able to kill children and animals, cripple
adults and result in law suits. If much of the mortar is missing, it is
most likely dangerous.

One logical solution is to clear out the mess between the bricks and
insert fresh mortar. Suitable mix depends on brick type, but 1:1:6 is
normally fine. Muck can be got out with a big angle grinder. Obviously
it is important not to clear much out at once, as youre taking away the
walls support in places and its already iffy.

The other logical solution is to rebuild it. You can just pull it down
and build, but if you do that theres always a risk of earth collapse,
plus any structure near the ex-wall, and those can cause injuries etc
too.

Finally I would not buy just add water mixes, but mix your own,
otherwise youre liable to end up with an unsuitable mix.
Hard bricks: 3:1 sand:cement by volume
soft (eg Victorian) bricks: 1:1:6 lime:cement:sand

Do not add a mortar face to the wall, this will trap water and may
increase the load on it substantially. As well as not solving the
problem. Can cause other problems too.


NT