Block paving - Block paving drive

[susanmoore1]

I have had a blocked paving drive for 1and a half years now and have noticed that there are uneven lumps on the drive. Does anyone know why this is happening they are noticible in various places thankyou

[lutonlagerlout]

Its probably subsided due to incorrect installation
your first job is to ring the installer and ask him to rectify it
regards LLL

[susanmoore1]

Thanks for that we will contact the installer who apparently does a lot of work for the council so we thought he was good it cost us 4,000 so we need it rectifying

[susanmoore1]

does anyone else know what might be causing this problem we have noticed it more recently and where the cars are parked on it most of the time it seems to have sunk which we thought happened because of the weight of 2 cars on it is this true

[jay-Manor Driveways]

no it shouldent sink , if you drive on the same line all the time and the job isnt up to scratch it will show up soon enough just like yours has
ring the guy and get him to fix it

[Rich H]

It's not unusual for there to be a small amount of settlement. A few mm isn't that strange after 18 months but any more could be indicative of an ill-prepared sub-base. The undulations are a bit more worrying that the depressions caused by the vehicles, IMO.

Do you have a warranty? Do you recall what specification they gave you for the construction? What was the sub-base material.

[lutonlagerlout]

i bet its "road planings" or " crusher run"
subbase is either insufficient ,or the bedding course is too thick ,basically the installation must have failed, we had 1 like this where the subbase was 400mm thick one end and wasnt compacted enough,had to take up and redo gratis
LLL

[Dave_L]

Many subase failures are caused by poor/inadequate compaction - people scrimp on the compaction equipment.

[susanmoore1]

thanks for that advice dave my husband thinks that its because we are on a hill and our garden slopes so he has gone with the sopes etc

[Dave_L]

Hmmmm have you any pictures you could post up for us to see the problem Susan?

[lutonlagerlout]

slopes make no difference to installation,
LLL

[matsfc]

My guess is too much sand, if its a decent company they will use enough stone foundation but lots seem to overlook the fact that less is best when it comes to the grit sand.
That said- some people are just unlucky- sometimes the earth beneath u just moves.
Best to lift a few blocks where a car doesnt go, dig down to under the foundation and take pics and show us- will be easy for you to put back. Stone foundation should be minimum of 4", grit sand maximum of 1".

[lutonlagerlout]

checked your site out matsfc,looks like you put a lot of hard work in to that
some good advice there,but is indian sandstone mined? or do you mean quarried?alos the pictures are a little small

but its a gazillion times better then anything i could do
fair play to you
LLL

[Rich H]

Stone foundation should be minimum of 4", grit sand maximum of 1".

Grit sand course is more likely to be 35-40mm and a lot of people are still laying it 50mm. 25mm would be really skinny.

[msh paving]

if you used 20mm dia. conduit as a screed rail, you would struggle to get 25mm of screed sand to work,as a 6mm bump in the sub-base would stop the rails following the required falls

MSH