New build house retaining wall problem

Wildsurf

Our garden has a retaining wall at the bottom of the garden. The house is 6yrs old the wall is made of vertical vertical posts that are approximately 90cm high at one end decreasing to 30cm at the other end. This morning we noticed that 1 of the posts has collapsed and fallen away and is clearly rotten. A number of the other posts look to also be rotten. 
I'm not happy that the retaining wall has only lasted 6yrs might we have a claim under out NHBC warranty? If not might it be possible to claim on our insurance? It does not seem unreasonable to expect the wall holding up the garden to have been designed to last a lot longer than 6yrs?
Any advice greatly appreciated.

greatcrested

I doubt NHBC ill cover it - read the terms of the policy.

Your insurance won't cover it (unless the collapse wascaused by fire? Or theft? or storm?) as it'salmost certainly a maintenance issue.

* I assume the posts are wooden? Wood rots. Have you been maintaining the wood?

Out of interest, what is between the posts and what is the other side (being retained)?

Slithery

Have you been treating the wood? I do mine at least once a year.

Jeepers_Creepers

I suspect you haven't a claim, Wildsurf.

'Treated' timber these days is nothing like to used to be. I understand they had to stop using the more toxic chemicals for preservation, and the alternatives just don't have the same effect. That, alongside almost certainly poorer-grade, very fast growing lumber, essentially means that posts in the ground will rot, and very quickly.

Adding further treatment on a regular basis usually won't help either, since the rot occurs at ground level or just below, where externally applied treatment won't reach.

Sis bought a house that was around 8 years old, and half the timber fence posts - and these were a hefty 6"x4" - had rotted clean through at ground level. The fencing itself - being above ground - was absolutely fine. When I replaced them, I found that the posts were set in concrete, and that the section below ground could, in most cases, be literally scooped out of its concrete shell - the rot was that bad. 

She also had a retaining wall made of 3' high round posts, again set in a concrete trench. And, again, rotted right through at ground level. I replaced these with 8"x4" pressure-treated sleepers.

Your best bet, therefore, is to set concrete posts in to the ground, and then use something like sleepers laid horizontally to 'shutter' between them. It's probably worth even laying a sheet of plastic on the 'earth' side of the sleepers to keep them from being permanently damp. If you must set new timber posts below ground level, then look at ways of sealing the outsides using, say, bitumen, paints like 'Black Jack', or even sleeving them in plastic (but prevent water from entering from above).

I doubt very very much you have a claim. 

Unicorn_cottage

Housebuilders use the cheapest possible materials and then walk off site and leave the homeowners to pick up the problems that soon appear sadly. Can you post a picture of the structure?

Wildsurf

Not the best photos but shows that the "wall" is just a series of vertical posts with no horizontal support at all. Even we had treated the visible side surely the rot would have started on the other side which is just up against the soil. It is the lack of a horizontal support that seems a fundamental flaw. Even the better look poles are wobbly from.lack of support and weight of the soil.they are supporting.
I wasn't optimistic we'd be able to claim on anything but it is definitely sub-standard design in the first place that seems to be the issue here.

Unicorn_cottage

Wildsurf said:

Not the best photos but shows that the "wall" is just a series of vertical posts with no horizontal support at all. Even we had treated the visible side surely the rot would have started on the other side which is just up against the soil. It is the lack of a horizontal support that seems a fundamental flaw. Even the better look poles are wobbly from.lack of support and weight of the soil.they are supporting.
I wasn't optimistic we'd be able to claim on anything but it is definitely sub-standard design in the first place that seems to be the issue here.

Yes that really is shockingly poor design. Is the path yours or communal or something else?

Wildsurf

Unicorn_cottage said:

Wildsurf said:

Not the best photos but shows that the "wall" is just a series of vertical posts with no horizontal support at all. Even we had treated the visible side surely the rot would have started on the other side which is just up against the soil. It is the lack of a horizontal support that seems a fundamental flaw. Even the better look poles are wobbly from.lack of support and weight of the soil.they are supporting.
I wasn't optimistic we'd be able to claim on anything but it is definitely sub-standard design in the first place that seems to be the issue here.

Yes that really is shockingly poor design. Is the path yours or communal or something else?

It doesn't belong to us, it leads to the gardens of the houses that back onto ours. No idea who legally owns it, just that it isn't us.

Unicorn_cottage

Wildsurf said:

Unicorn_cottage said:

Wildsurf said:

Not the best photos but shows that the "wall" is just a series of vertical posts with no horizontal support at all. Even we had treated the visible side surely the rot would have started on the other side which is just up against the soil. It is the lack of a horizontal support that seems a fundamental flaw. Even the better look poles are wobbly from.lack of support and weight of the soil.they are supporting.
I wasn't optimistic we'd be able to claim on anything but it is definitely sub-standard design in the first place that seems to be the issue here.

Yes that really is shockingly poor design. Is the path yours or communal or something else?

It doesn't belong to us, it leads to the gardens of the houses that back onto ours. No idea who legally owns it, just that it isn't us.

Yes but your garden is going to collapse onto that path. I know you probably know already but you need to devise a suitable solution to retain the soil. Concrete posts and gravel boards? Ultimately is gonna cost you a few quid.

Wildsurf

Unicorn_cottage said:

Wildsurf said:

Unicorn_cottage said:

Wildsurf said:

Not the best photos but shows that the "wall" is just a series of vertical posts with no horizontal support at all. Even we had treated the visible side surely the rot would have started on the other side which is just up against the soil. It is the lack of a horizontal support that seems a fundamental flaw. Even the better look poles are wobbly from.lack of support and weight of the soil.they are supporting.
I wasn't optimistic we'd be able to claim on anything but it is definitely sub-standard design in the first place that seems to be the issue here.

Yes that really is shockingly poor design. Is the path yours or communal or something else?

It doesn't belong to us, it leads to the gardens of the houses that back onto ours. No idea who legally owns it, just that it isn't us.

Yes but your garden is going to collapse onto that path. I know you probably know already but you need to devise a suitable solution to retain the soil. Concrete posts and gravel boards? Ultimately is gonna cost you a few quid.

Already had someone out to give us a quote.

greatcrested

I'm really no expert but two things I'd make sure about when you fix this

* don't use wood

* make sure water can escape