Repair a crack in a wall.

Hi, my son came down to paint the garden wall and found this crack in it. Looking at the coping, it has obviously been hit and I would bet it has been one of the 40ft lorries which are increasingly using our road. This left hand corner is really too sharp for them.
I've been reading up about reinforcing with rebar and epoxy, and would be grateful for any observations and advice please.

Looks like foundation movement.

It's a garden wall. Just fill it and paint it.

Thank you Mr ? Woody. I've had a great deal of help from posters on this site when spending several years DIY gutting, renovating and extending a house to retire to.
I have noted your frequent "helpful" posts to others and made my own judgement on them as I do with that one !!.

Rake/remove horizontal mortar joints about 50% wall thickness deep (don't do very long stretches in one go if the crack is low in the wall - don't want it toppling over!) for 30-50cm each side of the vertical crack. Insert a stainless steel helical rod. Inject epoxy/polyurethane type resin to bed the helical bar. (You can get expensive thixotropic mortar, I think from Twistfix? for that). Repack/point the rest of the joint with mortar. That should bring the wall back to original strength. If the foundations continue to fail, more cracks might appear - possibly at one or both ends of your repair! That's the best as I remember how we did it about 12 years ago on an 8 metre high 1 inch crack - still good to this day.

Oh, just noticed photo showing its a retaining wall. You might want to have the bar going 50cm or even 80cm each side of the vertical crack. And put one bar in every 2 courses / 8 inches to help make it really strong. There are raking bits you can get to put onto a normal small grinder that make that a quickish (and extremely messy, even with the vacuum attachment available) job.

i’m with woody .it hasn’t obviously been hit.
it’s more likely the weight of the lorries have an impact on the foundation.
therefore reinforcing it with rebar and other innapropriate remedies will cause the wall to pull itself apart every time extra lorry weight is put next to it

The problem isn't the wall but the lorries. They could bump it or shake the ground. Can you not report them to the council to restrict the size of vehicles that is allowed to pass? It should be illegal for vehicles to go on the pavement.

If it takes them 20 years to work out a solution and you absolutely hate cracks, you could rebuild the wall with something more sturdy like they do with sea walls using big boulders and also to yield some space.

The wall has an "expansion joint" sited about 750 / 1.0.m to the right of the crack

Looks like the crack goes down and on-to / in-to / through the concrete? at ground level.

The Helibar / Twistfix [as suggested] repairs would require the rough cast to be removed, leaving a very, very "obvious" patch. but you could stop the roughcast removal on one side at least at the expansion joint?

Short of a seriously major job to remove the wall, because of the height of retained earth the Helibar / Twistfix way, looks like a way to go?? imagine you have the wall removed to work on the Foundations and 2 /3 / 4 X 40 Tonne lorries roll past? the earth will move but not in a good way? or what happens if the lorry wheels drop into the new foundation excavation?? never mind the "work space" needed on the pavement?

Suggest you consider the Helifix option? combined with the introduction of a "Dummy" / "Fake" vertical expansion joint about 1.0.m or so the the left of the cracks, that way you will have some control over the area of roughcast you remove and a reasonable looking patch between two vertical expansion joints.

As for Helifix, visit their web site they generally suggest a 1.0.m on each side of the offending crack, in the height of wall you have I would install at least 3 bars spaced evenly over the height??

Ken.