The leaning wall of worry.

[SteWood]

Hi Folks

I've got a stone wall approx 8/9 ft high on the boundary of my garden that is leaning rather badly into my neighbours garden (see the attached photos). It's not as tall on their side as the ground raises up but I'm concerned it may fall on them and squash them! It's construction is concrete render on a stone wall which for much of it is a single skin thick.

My question is how best to rebuild the wall to ensure that it doesn't lean again. I was thinking of potentially building it partly out of hollow concrete blocks with some steel in and filled with cement (like a retaining wall) but is that overkill? I'll check out the depth of the foundations when I rebuild it and dig deeper if I need to. I might reduce the height of it but I do want it to have the stone exposed to look a bit nicer than it does now.

Thanks
Steve

 

[Doggit]

It's possible that the extra weight of the render has caused the wall to tilt, but as the ground rises up on their side, you can't underpin it. You'll very likely need to remove it, redo the foundations, and then rebuild it. The wall is straight, so the construction was fine, and using hollow concrete blocks might allow you to leave the foundations as they are, but if you want the exposed stone, then you'll very likely need to extend the foundations. Once you've got the wall down, you can check if there's reason that the foundations are giving way on the other side such as water coming down the neighbors garden.

 

[bobsuerita]

the best thing you done was remove that ivy

 

[tony1851]

The horizontal cracks suggest sulphate attack of the mortar, probably caused by the rendering, and higher earth on the other side, trapping in moisture. How thick is the existing blockwork?

 

[SteWood]

Thanks for the replies. There aren't any concrete blocks currently just the stones at approximately 12 inches depth.

 

[^woody^]

The lean appears to be quite uniform, which suggests a foundation problem. If so, the cracking is a separate issue and not the cause.

If this has occurred progressively over a relatively recent period of time, and the wind blows around there, then you need to sort it out quickly.

If there are trees or leaking drains involved - either yours or the neighbour's, then you could attempt to put these as the cause and claim on the insurance - again either yours or the neighbour's policy.

 

[SteWood]

Ok thanks a rebuild and upgrade to the footings then. I'm going to do this myself as the wall is my responsibility and I enjoy doing this stuff.

 

[Notch7]

Ok thanks a rebuild and upgrade to the footings then. I'm going to do this myself as the wall is my responsibility and I enjoy doing this stuff.

Just as well you enjoy it! Thats a fair bit of work

Why does the brick wall drop down? Its almost like the higher section of brickwork acts as a retaining wall with the stonework above.

When you remove the wall, you will need to cut back the neighbours soil as well to create room to dig the footing.

Stonework will be dear unless you happen to be in an area with local quarries.

 

[SteWood]

Hi

Will I need to keep the neighbour's soil back somehow or is it just whilst I build the wall? The brick wall dropping down is a bit random and just seems to be an extra bit to a retaining wall that's out of shot that runs at a right angle to this wall and separates my back
Lawn at a higher level from a Victorian extension at the back of my house which is on a lower level.

 

[Notch7]

Hi

Will I need to keep the neighbour's soil back somehow or is it just whilst I build the wall? The brick wall dropping down is a bit random and just seems to be an extra bit to a retaining wall that's out of shot that runs at a right angle to this wall and separates my back
Lawn at a higher level from a Victorian extension at the back of my house which is on a lower level.

Only while you build the wall. You will need some weep holes to stop water pressurr building up on the other side.

 

[stuart45]

How much of that wall is a retaining wall? You normally need a proper drainage system in place behind them. A really tall wall like that needs to be built correctly with regard to the subsoil and other conditions. Have a look online for the minimun thickness for it's height.

 

[^woody^]

One cause of foundation failure of retaining walls (though not the only one) is concentrated ground water at the back of the wall and foundation.

Read up on drainage behind retaining walls. Consider a land drain on the neighbour's side, or weep hole/pipes coming through to your side.

Also, a cause or contribution to that horizontal cracking is poor copings and poor drip overhang. Pay good attention to copings.

 

[SteWood]

Thanks Woody yes will go with weep holes and make sure water runs off the top of the wall sufficiently with slanted coping stones.

 

[Doggit]

How high is the ground on your neighbors side, and some pictures from that side would help. You may well need to cut the bank back to get the increased foundations in, and as per Woodys suggestion, you could put in weep holes your side of the wall, but you may end up with a hell of a puddle in your garden, so this idea needs a bit of thinking about. You may want an impermeable membrane on the other side of the wall, and a land drain in the neighbors garden, but not along the wall, as that might undermine the wall again.

 

[SteWood]

Ok thanks the ground is about 4ft higher on their side.