Retaining wall question - Is this safe? Do I need to take action?

Hi all, we recently bought a house with a rear garden that slopes uphill. The back wall of our garden appears to be made of a red brick wall approx 2m high. Abvove the top of this brick wall, our neighbours have a deck that starts about 7ft higher than our patio or about 6in higher than the brick wall. (level with their ground floor exit).
I always assumed the brick wall was just facing brick in front of a retaining wall, or that the space behind it is mostly a void.

Much to my surprise today I discovered that the space behind the wall is completely backfilled with soil/rubble and it is only a half brick wall, I cannot see any reinforcement there. I drilled through it to test at a few heights and after the half brick, there is no resistance at all and feels like soil.

What makes this probably a little bit better than it sounds at first; the houses and gardens are offset, the section of brick wall only spans about 7ft before it reaches the wall between us and neighbours. But then the rest of the wall seems to go on the same way.

Please see my very professional drawing + pictures, and let me know if I can safely ignore this or if something should be done?

(addendum
Reason I'm asking the question is; I have previously been told that to build a retaining wall greater than 3ft in height, it should be made at least full brick thick, or by laying concrete blocks on their belly or there is a risk the wall could topple.

The concern is that there is potentially 2x2x2m = 8 cubic meters of soil pressing against this wall - so about 12 tonnes in weight? What happens if there is a heavy downpour and it wants to start sliding downhill? Will a half brick wall hold?


I guess I'm looking for one of the following answers:
a. "Yes it will hold, for a section of retaining will that's only 7ft wide, half brick is fine"
b. "Maybe it's fine because it seems to be holding, and there isn't really any regulation/guidance/code that it breaks"
c. "Maybe it's not fine, but it doesn't break the rules so just ignore it"
d. "No that's dangerous and you should go knock on their door"

What seems to be the problem with the wall itself?

what are you wanting to ignore?

mattylad said:

What seems to be the problem with the wall itself?

what are you wanting to ignore?

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Thank you for your reply Matt.

You're right, there is nothing happening to this wall right now, it seems to be holding.

Reason I'm asking the question is; I have previously been told that to build a retaining wall greater than 3ft in height, it should be made at least full brick thick, or by laying concrete blocks on their belly.

The concern is that there is potentially 2x2x2m = 8 cubic meters of soil pressing against this wall - so about 12 tonnes in weight? What happens if there is a heavy downpour and it wants to start sliding downhill? Will a half brick wall hold?


I guess I'm looking for one of the following answers:
a. "Yes it will hold, for a section of retaining will that's only 7ft wide, half brick is fine"
b. "Maybe it's fine because it seems to be holding, and there isn't really any regulation/guidance/code that it breaks"
c. "Maybe it's not fine, but it doesn't break the rules so just ignore it"
d. "No that's dangerous and you should go knock on their door"

It looks like it has one drainage hole at the bottom already, but if you concerned about the water build up. Rake out some of the mortar joints and pop in a few weep vents at the bottom.

I've been trying to research the issue at hand, and stumbled across this; https://www.gov.uk/guidance/your-garden-walls-better-to-be-safe

It states the maximum height of a half brick wall in my area is 525mm (my question is about a half brick wall 2000mm high..)

It further states that

Such walls are amongst the most common forms of masonry to suffer collapse, and they are unfortunately one of the commonest causes of death by falling masonry.

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And finally

Seek expert advice if your wall exceeds the recommended height, or in circumstances whereby this guidance is inapplicable e.g. walls incorporating piers, or walls supporting heavy gates or retaining soil.

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I guess I'm going to look for local structural engineers.

I'm no bricky nor the type of engineer you need so cannot possibly say either way.

Looks like a full bricks width to me, do you mean it should be 2 bricks thick?

The best thing you can do is to get a suitably qualified structural engineer out, who has experience in such matters.

Be prepared to pay them for their inspection, and expect the remedial work required to be rather costly!