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Posted: Sat Apr 05, 2008 11:15 am
by Germainb
I have recently had a new block paved driveway installed on a clay-sub-base. The contractor installed the usual stone and then sand laying base for the pavers. They were unable to finish the drive due to wet weather. We have had some rain and the drive doesn't dry out making completion impossible. They have lifted a number of pavers to find the sand water logged. Note sand was not applied to joints because of the rain and so the drive was not compacted either. How can they solve the problem of the ground drainage and are there any other recommendations? I have seen the topic discussing the use of a geo-membrane but unless the clay can be drained, I don't see this as an answer. Please help!
Posted: Sun Apr 06, 2008 1:56 am
by lutonlagerlout
it should dry out sooner or later
i assume the drive falls in some way?
LLL
Posted: Sun Apr 06, 2008 7:19 am
by seanandruby
always get sand into the joints before going home.
Posted: Sun Apr 06, 2008 5:22 pm
by Pablo
As LLL says you're gonna have to wait till it's dry. As long as it's only foot traffic then no damage should be done anything heavy and you may have a problem. The jointing sand will have little effect on the amount of water getting into the bedding course so thats not the problem. Waterlogged bedding course on the other hand is an issue that may not resolve itself and it will already have had some compacting before laying so it wasn't in any way loose. Loose sand is very water retentive. Was the sand of a course paving type or was it a building sand type. If the problem is with the sub grade then you may have to start again. Before that i would try compacting and slurry sanding but as a last resort and see how it goes. Once i saw a driveway that the builder had used plastic instead of membrane on the base which had a tanking effect and waterlogged the sand. They had a caniary when they saw my quote for repair.
Posted: Sun Apr 06, 2008 9:10 pm
by Tony McC
If the laying course is waterlogged, that indicates the sand is the wrong type and/or the sub-base is wrong and/or both.
Knowing that the sub-grade was heavy clay, steps should have been taken to ensure adequate drainage of the sub-base via fin drains, edge drains, or some other way of getting water out of the conventional sub-base material and so avoiding any problem with liquefaction.
The fact that the contractor did not then, and hasn't since, put any jointing sand onto the pavement suggests they are not as clued-up as they'd have you believe.
Posted: Mon Apr 14, 2008 7:07 pm
by Germainb
Thank you all for your valued comments.
The contractor has agreed to lift the flat portion of the drive and start again. The drive has been layed with adequate falls and linear drainage. Even if the drive is re-laid and sanded and compacted, water will still enter the sub-base and not be able to drain away. I am now convinced that once the drive is up, some forms of land drainage is applied.
What will be the best method? Perforated hard plastic pipes that drain into my existing drainage system or fin drains? Without some form of land drainage, I just can't see this working. Sand and sub-base construction used correct materials. I am convinced sub-base becomes waterlogged after it rains and then takes time to dry out!
Posted: Mon Apr 14, 2008 11:28 pm
by matt h
see main site ref fin drains, and suggest your contractor does the same!;)