Retaining wall woes

Amorton10

Hi all,

Hoping for some thoughts/advice here please. We have been in our new home just over a year now and six months ago our neighbour brought to my attention a crack in the retaining wall between our back gardens. The deeds indicate this wall is my responsibility. Our garden is approx 1m higher so was something we could never have seen. I've had a few quotes to rebuild and they have come back in the region of £8,500. I gather this is the norm for a retaining wall 8m x 1m, replacing all footings at the same time.

While not apparently unreasonable this is an awful lot of money. therefore, firstly I'm wondering about using concrete gravel boards to retain my garden with a regular 6x6 ft wooden panel fence in front to hide them so it looks better for the neighbours. Would this be strong enough to hold back our garden given the 1m height difference? Also are there likely to be any potential legal implications if we do this as it's not "like for like"?

Secondly, every builder I've spoken with has said this crack would have first started to appear much longer ago that the year we've been living here. The neighbour said they didn't see it as they had things up against the wall. I'm therefore thinking that this issue should have been resolved before we even moved in. They also said when we first spoke that they would possibly contribute to the cost but, like me, I'm sure they weren't quite aware of how expensive retaining walls are to rebuild! What do you think a reasonable contribution would be?

Thank you for reading and any thoughts

Grenage

How bad is the crack; why does the whole wall need to be rebuilt?

stuart45

Have you any photos of the wall?

Amorton10

Grenage said:

How bad is the crack; why does the whole wall need to be rebuilt?

When the houses were built this wall was poorly finished. It's fine up to a point but past that point as it gets further from the main building the footings aren't deep enough and it's sinking which is what I'm told is causing the crack. It's like it was built in two sections, the section furthest from the house almost being an afterthought or built by apprentice. The section closest to the house is absolutely fine. There's an obvious difference in the quality of both the bricks and the mortar. The houses are about 20 years old 

Amorton10

Grenage said:

How bad is the crack; why does the whole wall need to be rebuilt?

Meant to add that only the section furthest from the house is being rebuilt. Unfortunately that's 8 metres!

Amorton10

stuart45 said:

Have you any photos of the wall?

I do but not with me. Will try and post a little later. It's pretty bad and there has been no difference in opinion between 4 completely separate independent builders. 

Will try and put something up later though as all opinions are appreciated. Thanks

Section62

Amorton10 said:

While not apparently unreasonable this is an awful lot of money. therefore, firstly I'm wondering about using concrete gravel boards to retain my garden with a regular 6x6 ft wooden panel fence in front to hide them so it looks better for the neighbours. Would this be strong enough to hold back our garden given the 1m height difference?

I'd say it is unlikely to be strong enough unless the gravel boards are themselves supported by a substantial structure with good foundations.  Gravel boards aren't specifically designed to take significant sideways loads, so I would expect them to crack and fail in due course.

Much of the work involved in replacing the wall will be in the excavation and foundations - the type/appearance of the wall above the lower ground level will only be a part of the cost.

If I was your neighbour I wouldn't be happy with a bodge job, especially one which doesn't look that attractive. And definitely not one which involves things being built on my garden rather than on the boundary.

Amorton10 said:

Also are there likely to be any potential legal implications if we do this as it's not "like for like"?

There was a useful feedback thread on the forum recently about a court case touching on the "like for like" issue.  In that case the judge decided that the wall should be built back better than the original.  Which isn't entirely unreasonable when the previous wall has failed.

I've tried finding that thread without any success so far, but will keep looking (unless someone else links to it first).

theoretica

Amorton10 said:

Secondly, every builder I've spoken with has said this crack would have first started to appear much longer ago that the year we've been living here. The neighbour said they didn't see it as they had things up against the wall. I'm therefore thinking that this issue should have been resolved before we even moved in. They also said when we first spoke that they would possibly contribute to the cost but, like me, I'm sure they weren't quite aware of how expensive retaining walls are to rebuild! What do you think a reasonable contribution would be?

Sorry - if you had asked your surveyor to look at the wall and known about the crack you might have negotiated with the seller, but a problem nobody realised until now is no longer their issue. 

If your neighbours have cosmetic preferences which make the wall more expensive they should be prepared to pay for that.  Otherwise it is a matter of gratefully accepting whatever they offer as they don't need to give anything.

Do you need a step height difference at all?  I wonder if completely reworking your garden to have a slope or a series of small terraces would appeal to you and what that would cost?

stuart45

There are some DIY retaining wall blocks on the market for low retaining walls like this one. Don't use mortar or require a special foundation. 
I've never used them myself as they are designed for DIY use, but can see they could work in some cases.

FreeBear

stuart45 said: There are some DIY retaining wall blocks on the market for low retaining walls like this one. Don't use mortar or require a special foundation.

Do you mean Gabion Crates ?

If properly sized, they may well be an option.

stuart45

Gabions could be another option, but these blocks are similar to the 9 inch hollow blocks, but are dry stacked and put a batter on the wall as they step back slightly on each course.
Popular in the USA where Allan blocks are the name of a common brand.
I would guess that once the first course is laid spot on, it's a pretty simple job to build the wall.
Like gabions they allow moisture to escape and have enough flexibility to cope with ground movement.