The Brew Cabin

Posted: **Fri Oct 04, 2013 2:42 pm**

Hi all,
apologies if this has already been covered, I searched for a while but couldn't find a definitive answer so would appreciate any guidance!

We are relaying our driveway with gravel, laid on top of Type 1 (clay soil, terram, 150mm type 1, 40 mm gravel). My only concern is with drainage, as I'd always assumed that as the gravel will be free draining it wouldn't be an issue but the clay soil doesn't seem to drain too well and has pooled quite a bit after 3 days of rain.

What is the best practise? Should I lay drainage anyway (going to the existing surface water drain or fin drain) or will it drain itself? There is a strip of garden about 2m wide running up the side of the drive which I could also slope towards if necessary.

Thanks
Sam

Posted: **Mon Oct 07, 2013 10:44 am**

Apologies for following up my own post, but just wanted to add a bit more detail...

I've been setting out and edging over the weekend, so we now have clear levels to work with - the house is on a mild downhill slope so drainage to the garden is not an option (as it's higher, and lowering it enough would not be feasible).

In my mind I have two options now:
1) Use a permeable sub-base (type 3 or equivalent) and trust the sub-grade to dispose of the water
2) User a type 1 sub-base and lay some perforated pipe down the middle of the drive as a land drain (in a trench of course, backfilled with suitable fill) as a drainage channel

I'm leaning towards option 2 at the moment, does it sound reasonable?

I don't see any point in surface drains (linear channel or similar) as I'm mainly concerned with removing water from the sub-base, not the the top gravel layer - is this the right approach or total ****?

Thanks
Sam

Posted: **Mon Oct 07, 2013 5:10 pm**

sam i think you are overcomplicating matters
gravel on top of compacted type 1 is fine
LLL

Posted: **Tue Oct 08, 2013 9:42 am**

Thanks for the info - I was just concerned that the Type 1 would compact down into an almost impermeable surface as leave the water with nowhere to go.

I guess if it does ever become an issue I can lay a land drain later on, just wanted to make sure before I put the base down.

Thanks
Sam

The Brew Cabin

Drainage needed for new gravel driveway?