Block paving drive - Sinking

[ian123]

I think I may have a problem, possibly?

I had a block paving driveway (basket weave pattern) laid by a local contractor around 7 months ago and until recently was very pleased with the job they had done.

However, I've noticed that where the wheels of my car sit has started to sink very slightly. It is only a very small amount and not noticeable unless you look carefully.

Is a small amount of sink acceptable/expected? It has taken 7 months for this to occur, could the blocks settle as they are now or is this the start of worse to come?

I'm unsure whether to wait and see if the drive deteriorates further or demand the firm correct it immediately. I assume the fix would be to lift and re-lay the entire drive?

Any advice would be very much appreciated.

[lutonlagerlout]

no its not acceptable, and basket weave is not an acceptable bond for vehicular traffic.
apart from the bond if it is sinking the installation is wrong
LLL

[ian123]

Thanks for the reply LLL.

I wasn't offered any advice on the selction of the block layout, I was told it was down to personal preference. Could this be the cause of the sinking or is that a separate issue?

If it has sunk slightly over 7 months of parking on it would you expect it to get worse or could it stay in its current state. In its current state it isn't too unsightly just annoying that it isn't as it should be.

I fear I may have been ripped off, it's so difficult to choose a contractor, I got 3 quotes and went for the middle one who also happened to be local and came recommended by a family friend.

[msh paving]

The reason people lay basket weave is so they have very few cuts and they think it is quicker,
but that bond has no way to stop movement in the blocks as they are not tied together
if it has sunk its due to lack of sub base compaction or depth off sub base not enough,or the laying sand too deep or not compacted ,i would ask him back to lift the sunk area as its only 7 months ago MSH

[ian123]

Thanks for the advice, I think getting him back is the best option.

What would be the correct way to fix the problem? best if I know what he should be doing so he can't fob me off.

Can he lift and relay just the effected area, if the sub base isn't deep enough will he not need to dig down depper and relay the whole drive?

[worldofpaving]

Ian,

I wouldn't escalate this into a dispute at this stage, talk of being ripped off is a tad premature. Errors are made sometimes, even by the best but a bit of damp sand bit of bulking thus slightly poor compaction, could cause a small problem like you describe.

Yes, the area affected can be "unzipped", recompacted and relaid.

Ask the contractor to come back and resolve it and if he is reputable, as the vast majority of installers are (despite Rogue Traders and other programmes of this ilk) he will pop round and have a look and do it without a fuss.

All the best,
WOP

[lutonlagerlout]

we had a drive sink once,we ripped the lot out and re did it,the subgrade was too soft which in retrospect we should of dug out,although it was just about .5m2 that sunk we took all 50 up and redid it
I dug out 400mm below FFl recently because the ground was poor,better safe than sorry
LLL

[Amogen]

Hi Ian,

As has been already stated, first point of call is to get the contractor back to correct the slight fault. Only escalate it if an acceptable remedy is not put in place.

You are not that far from us, and we specialise in the restoration of block paved driveways etc. If you get nowhere with the contractor and wish it to be sorted, please feel free to give us a call.

[ian123]

Well, I've contacted the contractor and he was round the next day to have a look.

His plan is as follows: lift the blocks in the effected areas, add more sand, compact, relay the blocks, add more jointing sand and compact again.

Does this sound like a feasible resolution to the problem?

[Amogen]

If they have only sunk a very small amount, it sounds like an adequate plan.

Keep an eye on the area following the repair, just in case it starts sinking again, although it shouldnt.

Keep us posted how you get on.

[Tony McC]

If it's a small area, and highly localised, then lifting and re0bedding is acceptable, but if it starts to happen elsewhere, or if it re-occurs in a 'repaired' area, that suggests the sub-base is inadequate.

[ian123]

Thanks for the advice.

The contractor has agreed to relay the sunken areas, which will hopefully solve the problem.

I may be worrying about nothing but: The drive (approx 40 sq m) is actually constructed in a basketweave layout at 45deg to the direction our cars drive on and off. I'm told this is unsuitable for vehicular traffic, however at the time of laying I wasn't offered any guidance from the contarctor along these lines so chose basketweave simply as an alternative to herringbone.

Is it possible for this layout to withstand vehicular traffic or should I expect problems in the future even if the sinking issue is resolved?

Is the contractor obligated to stick to the relevant BS or are they merely guidelines?

I really wish I'd read some of the advice in this forum before the drive was started!

[ian123]

Any thoughts?

[Tony McC]

The contractor ought to have informed you that a non-interlocking pattern was less than ideal, but it's difficult to claim that he was negligent.

As a non-interlocked pattern, it's likely to keep moving, but, assuming the edge courses are sound, there is a limit to just how much it can move. The problem is that it can move this way, and then, when it meets a brick wall, it might move that way.

Unless the contractor stated in his written quotation or receipt that his work does/will comply with the British Standards, then he's under no obligation to work to anything other than his own "standards". If this was a situation where the pavement was falling apart, sinking, moving by centimetres rather than millimetres, then you might be able to argue that it is "not fit for purpose", but what you have described so far falls well short of that, more 'shoddy' than shocking.

[ian123]

Thanks Tony, looks like I'll have to live with the basketweave and hope for the best.

Still no sign of the contractor returning to relay the sunken blocks, although he assures me that he will when he gets chance. I guess he'll be putting new jobs that he'll get paid for ahead of a job he's already been paid for.

Been having a read of your sealants section of the main site and I'm thinking that once he finally does relay the effected area I'll seal the drive with a urethane-based sealant.

One bit I read on this type of sealant says "and they have been shown to reduce the amount of settlement/deformation in a trafficked pavement compared to untreated block paving"

Could this help with the basketweave bonding issue also?