Retaining wall replacement
Discussion
I have a retaining wall down the side of my property. It's quite long (17m ish) and about 70cm high holding back clay soil. The wall is in poor repair and needs replacement (it's a single skin wall so perhaps not up to the task).
The wall is on my side and there is about 40cm of dirt until it reaches the boundary line (a fence - i've not idea if this is the actual boundary line, the houses are 70 years old and that is lost in the mists of time, and not a can of worms I wish to open!). The wall runs parallel with the wall of his house for about 5m and then it is his garden. It looks like there is some block work behind the bit that runs parallel with his house - not sure how far down this goes.
My understanding is that the person who's land is retained by the wall needs to maintain the wall - this is slightly muddied by the fact that the first 40cm of dirt is mine.
I've now got the first quote in for 12k for steel H beams augered and concreted in to a depth of 75cm and then sleepers - given it's close to the foundations of my house and they are not very deep I am not keen to have a strip foundation dug out etc (access is also not great). I'm not going to ask my neighbour for the full 12k - maybe 30% or something, but before I do that I thought I'd check I'd not misunderstood the rules.
(I'll also need to get a party wall surveyor I'm assuming :-( )
Behold my artwork!
The wall is on my side and there is about 40cm of dirt until it reaches the boundary line (a fence - i've not idea if this is the actual boundary line, the houses are 70 years old and that is lost in the mists of time, and not a can of worms I wish to open!). The wall runs parallel with the wall of his house for about 5m and then it is his garden. It looks like there is some block work behind the bit that runs parallel with his house - not sure how far down this goes.
My understanding is that the person who's land is retained by the wall needs to maintain the wall - this is slightly muddied by the fact that the first 40cm of dirt is mine.
I've now got the first quote in for 12k for steel H beams augered and concreted in to a depth of 75cm and then sleepers - given it's close to the foundations of my house and they are not very deep I am not keen to have a strip foundation dug out etc (access is also not great). I'm not going to ask my neighbour for the full 12k - maybe 30% or something, but before I do that I thought I'd check I'd not misunderstood the rules.
(I'll also need to get a party wall surveyor I'm assuming :-( )
Behold my artwork!
My understanding has always been the l
Person who's land is veing retained is responsible, quite how the gap between boundary would work I'm unsure.
12k isn't cheap, my maths that's 8 1500mm steel H sections, assuming you'll want them galv, 25 bags postcrete and 21 sleepers at 8ft each. That doesn't add up to 12k, 2 guys, 2 days, micro digger and auger.....I'd say they don't want the job at that price
Person who's land is veing retained is responsible, quite how the gap between boundary would work I'm unsure.
12k isn't cheap, my maths that's 8 1500mm steel H sections, assuming you'll want them galv, 25 bags postcrete and 21 sleepers at 8ft each. That doesn't add up to 12k, 2 guys, 2 days, micro digger and auger.....I'd say they don't want the job at that price
The wall is on your land so it's your wall.
Rule of thumb engineering you'd want a sheet pile wall 1.5m into the ground and occasional posts significantly deeper.
Given the proximity of the houses a pressed sheet steel pile wall on the boundary line is probably favourite, ideally, although access and reach may be problematic.
There are many other solutions, such as concrete 'Lego' blocks. First thing is to get a structural engineer to produce a design to your requirements, especially how much room you want.
Rule of thumb engineering you'd want a sheet pile wall 1.5m into the ground and occasional posts significantly deeper.
Given the proximity of the houses a pressed sheet steel pile wall on the boundary line is probably favourite, ideally, although access and reach may be problematic.
There are many other solutions, such as concrete 'Lego' blocks. First thing is to get a structural engineer to produce a design to your requirements, especially how much room you want.
Thanks for the comments.
Access is a pain for sure, and it's heavy clay they'll barrow out. I assume there is a 'it's a pain in the rear' premium but I am will to accept that to a degree (this is only the first quote) - the quote is not that outrageous (west berks) and it is very thorough and detailed, so I assume it's not a 'go away' quote.
The quote is for 15 H beams (they're suggesting every 1.2m) which seem to cost about 85 quid when I look online (£1300). Then i'd guess 105 sleepers, so that's another £2500 ish. Maybe add on a generous £2k for tools, skip, concrete etc. So maybe 6k for materials. Then labour - I'll need to find out how long they think it'll take.
It's been a pain getting people to turn up to quote.
The wall is about 20 years - dates from one of the extensions I think. When we got the house it was propped up (4 years ago) so who knows how long it'd been like that for.
I plan to get a party wall surveyor out for sure - any suggestions in west berks?
Access is a pain for sure, and it's heavy clay they'll barrow out. I assume there is a 'it's a pain in the rear' premium but I am will to accept that to a degree (this is only the first quote) - the quote is not that outrageous (west berks) and it is very thorough and detailed, so I assume it's not a 'go away' quote.
The quote is for 15 H beams (they're suggesting every 1.2m) which seem to cost about 85 quid when I look online (£1300). Then i'd guess 105 sleepers, so that's another £2500 ish. Maybe add on a generous £2k for tools, skip, concrete etc. So maybe 6k for materials. Then labour - I'll need to find out how long they think it'll take.
It's been a pain getting people to turn up to quote.
The wall is about 20 years - dates from one of the extensions I think. When we got the house it was propped up (4 years ago) so who knows how long it'd been like that for.
I plan to get a party wall surveyor out for sure - any suggestions in west berks?
ewanjp said:
I plan to get a party wall surveyor out for sure - any suggestions in west berks?
https://pyramusandthisbesociety.org/find-a-surveyo...This would be a good place to start.
The P&T Society is a specialised place for party wall matters.
ewanjp said:
Thanks for the comments.
Access is a pain for sure, and it's heavy clay they'll barrow out. I assume there is a 'it's a pain in the rear' premium but I am will to accept that to a degree (this is only the first quote) - the quote is not that outrageous (west berks) and it is very thorough and detailed, so I assume it's not a 'go away' quote.
The quote is for 15 H beams (they're suggesting every 1.2m) which seem to cost about 85 quid when I look online (£1300). Then i'd guess 105 sleepers, so that's another £2500 ish. Maybe add on a generous £2k for tools, skip, concrete etc. So maybe 6k for materials. Then labour - I'll need to find out how long they think it'll take.
Where do you get 105 sleepers from? 17m is pretty much 7 x 8ft sleepers, and 70cm is 4 high (assuming long edge up) so that would only be 28? Access is a pain for sure, and it's heavy clay they'll barrow out. I assume there is a 'it's a pain in the rear' premium but I am will to accept that to a degree (this is only the first quote) - the quote is not that outrageous (west berks) and it is very thorough and detailed, so I assume it's not a 'go away' quote.
The quote is for 15 H beams (they're suggesting every 1.2m) which seem to cost about 85 quid when I look online (£1300). Then i'd guess 105 sleepers, so that's another £2500 ish. Maybe add on a generous £2k for tools, skip, concrete etc. So maybe 6k for materials. Then labour - I'll need to find out how long they think it'll take.
It would be interesting to know what's really required to stop a 60cm height of clay soil from slipping sideways. In the short term the answer is "nothing". You can easily dig a vertically sided hole that deep in a clay soil. So long as it's just holding back garden, so it isn't being destabilised by moving massive weights back and forth across it, I expect you don't need much of a wall at all. There are centuries old dry stone retaining walls round here that are still in good nick. They slope back somewhat against the hill, but not by much. They key back into the soil, but even that is primarily about getting weight on top of the stones to hold them in place. The whole thing is held together by gravity and friction.
JimM169 said:
Where do you get 105 sleepers from? 17m is pretty much 7 x 8ft sleepers, and 70cm is 4 high (assuming long edge up) so that would only be 28?
My maths may be shot! The quote says 1.2m spacing between posts, so 15 gaps to be filled. Sleepers are 10cm tall, so seven per gap which then equals 105. However, now you've pointed out the obvious that they'll put them longways up, that means 60 sleepers ... I get they could use longer sleepers, but they've quoted for 1.2m spacing (the guy's company does retaining walls, so I assume he's chosen what is required).ewanjp said:
JimM169 said:
Where do you get 105 sleepers from? 17m is pretty much 7 x 8ft sleepers, and 70cm is 4 high (assuming long edge up) so that would only be 28?
My maths may be shot! The quote says 1.2m spacing between posts, so 15 gaps to be filled. Sleepers are 10cm tall, so seven per gap which then equals 105. However, now you've pointed out the obvious that they'll put them longways up, that means 60 sleepers ... I get they could use longer sleepers, but they've quoted for 1.2m spacing (the guy's company does retaining walls, so I assume he's chosen what is required).You are not sinkiing 6ft of sleeper into the ground to leave 2ft above ground.
An 8ft fence post only gets sunk 2ft deep to support a 6ft fence for instance.
ewanjp said:
Great that website gives me somewhere to start. Bizarrely most people come up as 'not currently practicing' but if you click on them, they are.
Strange.I've just checked my own listing and I also come up as "not currently practising". It must be an anomaly with the database, which I'll flag up with the site admin.
ATG said:
It would be interesting to know what's really required to stop a 60cm height of clay soil from slipping sideways. In the short term the answer is "nothing". You can easily dig a vertically sided hole that deep in a clay soil. So long as it's just holding back garden, so it isn't being destabilised by moving massive weights back and forth across it, I expect you don't need much of a wall at all. There are centuries old dry stone retaining walls round here that are still in good nick. They slope back somewhat against the hill, but not by much. They key back into the soil, but even that is primarily about getting weight on top of the stones to hold them in place. The whole thing is held together by gravity and friction.
Retaining walls are the only modern form of construction that you regularly see in a failed state. When you calculate the horizontal forces they are surprisingly high, particularly if the walls are not well drained. You can dig a small hole in clay with verical sides that will remain stable in the short term, less so a 17m long trench, especially once it starts to rain.Firstly, holding up 70cm of soil on a 1 in 3 slope is pretty trivial.
Secondly, it's pretty much the other guy's problem.
The idea of piling that close to your foundations is the worst suggestion on PH for a while.
Do you actually want the wall in the same place anyway? Would it not be better moved away from your house?
I don't think sleepers are a good idea, they don't last forever and most of those sold for 'landscaping' are pre-rotted things that have been in the ground too long already.
If the wall was jerry built at the same time as next door's extension, messing with it could be a world of pain if the extension is built to similar standards, you really don't want to get involved without the right professional advice and insurance cover.
Secondly, it's pretty much the other guy's problem.
The idea of piling that close to your foundations is the worst suggestion on PH for a while.
Do you actually want the wall in the same place anyway? Would it not be better moved away from your house?
I don't think sleepers are a good idea, they don't last forever and most of those sold for 'landscaping' are pre-rotted things that have been in the ground too long already.
If the wall was jerry built at the same time as next door's extension, messing with it could be a world of pain if the extension is built to similar standards, you really don't want to get involved without the right professional advice and insurance cover.
I'd for the wall to not be there, but it is, and I can't move it (there is no where for it to go). It appears to be very much my problem, hence I'm trying to sort it.
I believe the suggested method was using an arguer to make a 8 inch hole 75cm deep, then put the H beam in it, rather than trying to bash in anything (as it's next to my house). Presumably digging out a strip foundation would be much more involved and potentially risk my houses foundation. As pointed out sleepers don't last forever, but I don't plan to be here for ever and I assume should one go too rotted they can be pulled out and replaced.
I don't have the history of when the wall was built. It's the same brick type as the extension which was late 90s, so I assume then.
Here is a picture that shows the situation - as you can see - it's not ideal! The fence is in the bushes on the left hand size - it's probably 8ft tall.
I believe the suggested method was using an arguer to make a 8 inch hole 75cm deep, then put the H beam in it, rather than trying to bash in anything (as it's next to my house). Presumably digging out a strip foundation would be much more involved and potentially risk my houses foundation. As pointed out sleepers don't last forever, but I don't plan to be here for ever and I assume should one go too rotted they can be pulled out and replaced.
I don't have the history of when the wall was built. It's the same brick type as the extension which was late 90s, so I assume then.
Here is a picture that shows the situation - as you can see - it's not ideal! The fence is in the bushes on the left hand size - it's probably 8ft tall.
With my surveyors hat on, have you considered installing the new retaining wall closer to the fence line, so that once it is in place, you can remove the old wall and the part of the soil to create a wider path on your side?
I appreciate that there would be additional costs involved, and perhaps the extra width might not be useful or cost effective.
I appreciate that there would be additional costs involved, and perhaps the extra width might not be useful or cost effective.
I'd not considered that - ideally I don't want to spend more than I have to - 12k is already a decent chunk. There is a side path down the other side of the property. I guess it could be useful to have better access down there - I've never really considered it as the wall has been knackered since we've got here.
Looks like the wall is a result of the ground being dug away for your extension, and it's been done away from the boundary to avoid it being a party wall?
If I was your neighbour, I don't think I'd be in a rush to contribute to the cost, but I would be insisting on my party wall act rights.
It could be a bit of a legal minefield.
It might be useful to obtain copies of the planning permission etc from when the extension was built?
If I was your neighbour, I don't think I'd be in a rush to contribute to the cost, but I would be insisting on my party wall act rights.
It could be a bit of a legal minefield.
It might be useful to obtain copies of the planning permission etc from when the extension was built?
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