Another Retaining Wall Q

[pgtips]

Our retaining wall looks dreadful. Bricks blown, we painted it but the bricks keep blowing.
What do we do.?

End result would be nice to have the engineering top and paint the sides but want to have a solution that will last and looks nice.

Holding back the earth as you can see.

Some blown parts of the wall don't have earth behind, some do.

Can we recover anything of whats here, remedial?. Do we need to rebuild, engineering bricks/concrete blocks etc. These were Golden Buff, same as our bungalow bricks none of which have blown (pic attached of them), it looked really nice .. once . Painted it looked nice but we are fighting a losing battle.

Any advice appreciated.

Pg

 

[Ivor Windybottom]

They're London Bricks (LBC). They're known for being useless with frost, the worst possible choice for a garden wall. It was probably done to match the house, they're OK for a house as it will be heated and much drier, but even then they can still pop. They're rubbish.

Some off-the-cuff suggestions...

The real answer would be to replace it with better bricks. Ideally concrete ones, e.g. Marshall or similar. The good news is the foundation must be OK, if there are no signs of movement.

The workaround would be to replace the top with something that has a lip to stop the water running down into the bricks below before freezing and popping them.

It would be a waste of time rendering it as the bricks are falling apart so the render will probably come off.

Dig out behind and refill with 20mm gravel so the water can find its way to the drainage holes you already have.

 

[noseall]

Our retaining wall looks dreadful. Bricks blown, we painted it but the bricks keep blowing.
What do we do.?

End result would be nice to have the engineering top and paint the sides but want to have a solution that will last and looks nice.

Holding back the earth as you can see.

Some blown parts of the wall don't have earth behind, some do.

Can we recover anything of whats here, remedial?. Do we need to rebuild, engineering bricks/concrete blocks etc. These were Golden Buff, same as our bungalow bricks none of which have blown (pic attached of them), it looked really nice .. once . Painted it looked nice but we are fighting a losing battle.

Any advice appreciated.

Pg

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As posted above, i.e. LBC's are useless in a garden wall. You need to replace the wall with a brick that is FL rated......

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• noseall
• 20 Oct 2023

Al5

• noseall
• 2 May 2022

Al6

• noseall
• 2 May 2022

Drain2

• noseall
• 8 Apr 2022

Planter6

• noseall
• 22 Apr 2021

Planter5

• noseall
• 22 Apr 2021

Planter3

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• 22 Apr 2021

Planter4

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• 22 Apr 2021

 

[Ivor Windybottom]

I got some really cheap LBC mixed end-of-line bricks for 9p each a few years ago, all mixed varieties. I used them as brick paths on the veg patch. This was fairly commonly done in victorian gardens, the odd one got popped but they usually lasted decades. One winter later, they were red splinters and mush, all mixed into the soil. Big skip, got rid.

I suspect that LBC bricks were better in the past. Perhaps they're saving gas by only gently baking them these days, who knows but they're useless.

They're almost never used out of choice for newbuild - almost anything else is better and costs less. But they still sell at ridiculous prices to people who have to match what they already have, including muggins me.

 

[noseall]

I suspect that LBC bricks were better in the past.

No. They've always been tat. Genuine London's cost a fortune now (£1.20 per brick) too.

 

[Ivor Windybottom]

I know, I bought a load recently. £1.30 each, best price I could find. Upsetting as I know they're junk, but it's what the place is built out of.

 

[Ivor Windybottom]

I don't know how good the brick lookalike concrete ones are in reality. They'll be frostproof, but I'd guess they'll fade and turn grey/beige eventually, when the dye wears off exposing the aggregates that must be below the surface.

Decent clay ones may be the best bet. I actually really like the standard fairly cheap engineering bricks, they have a nice victorian look.

 

[pgtips]

Thanks everyone, helpful to know and understand the problem.

Bit of an update, There was a builder opposite who had a plasterer working with him. They came up with a solution to place a coping brick on the top with a slight overhang and also dig out behind and put in a sheet membrane barrier. Stop/reduce water penetration down and from the back.

For the front face, pressure wash clean it up, bond it, then add a mesh and then plaster it with a silicone plaster mix which is waterproof and doesn't need painting as its coloured.

He echoed the concerns about the brick, more surprise at how quickly they had blown but he observed its mostly the top layer of brick so water is more than likely getting through the top layer.

 

[Ivor Windybottom]

The membrane down the back is a good idea. I always use bitumen or similar waterproofing paint on the back of a retaining wall, a similar idea. Paint is probably preferable as it soaks right into the bricks and can't get punctured. But it probably won't work on one that's already been buried so is muddy. There will always be a route from the bottom of the membrane up behind it via groundwater pressure, as its bottom edge won't be attached to anything.

Definitely get some gravel behind the membrane too. Ensure there's a path to the drain holes, and that they don't get blocked by the membrane. It may (will) move after being buried.

I'd still be concerned about the render/plaster detaching, it's a risk but only time will tell. The risk-free answer would be rebuilding with decent bricks. It may sound like a more drastic course but in reality your builder's approach is still a lot of work and materials, there may be less difference between facelift and rebuild than you'd think.

Weathered LBC bricks remind me of pink wafer biscuits, once they start eroding they don't want to stop.

 

[stuart45]

You best chance for render is metal laths mechanically fixed to the masonry.
If you dig out the back for drainage, it's worth putting a geotextile membrane around the fill to stop any clay getting into it.
LBC flettons are baked at a low temperature, so although it made them a cheaper brick, it also made them less frost resistant.

 

[Ivor Windybottom]

Metal anything in a garden wall will eventually rust, galvanised or not. A retaining garden wall is a much harsher environment than a house wall, where the eaves overhang and there's always heat leaking out through the wall keeping it dry and frost-free.

It all depends on the comparative cost of facelift vs rebuild and how long you want it to look OK for. If selling in the next few years then it may make sense, if staying there for decades then it's a risk.

 

[stuart45]

They normally use stainless steel in those situations, although some people prefer plastic.

 

[Ivor Windybottom]

Fixed with what? I use stainless screws for everything outdoors on my own house but they cost loads and are pretty soft so you have to be careful with them, e.g. drill pilot holes and drive by hand only. I even ensure every washer and nut is stainless. But I wouldn't rely on anyone else to go to this sort of trouble.

But stainless can rust. No metal of any sort is vastly preferable.

 

[Ivor Windybottom]

https://www.reliance-foundry.com/blog/does-stainless-steel-rust

 

[stuart45]

The fixings have to be stainless as well. When done properly it lasts for a long time, although plastic and fibre glass are becoming more popular.
A garden wall, especially a painted one like that is not ideal for render, but if it is going to be done stucco lathing is better than direct to the masonry.