We're putting a driveway over our front garden, which because of drainage, is going to be made up of compacted type 1 with large gravel stones on top.
How deep would the type 1 need to be, and also how deep would you go with the gravel on top? I don't really want too much gravel if it can be helped, as I don't want to feel like I'm driving across Brighton beach every time I use it?.
Generally 150mm type 1. Although if the formation is super hard you may get away with less. Well compacted.
The gravel is just a dressing so 20mm or so. Try and get an angular gravel rather than round stones for less beach like feeling. Also mixed size aggregate.
The type 1 won't drain very well. Depending on what you need and usage it may be better going for a type 3 or similar. It may be more expensive but it will let water through better.
If you are on a clay soil a geotextile is necessary to be laid on formation to prevent the clay mixing with the sub base when trafficked to in wet moaths.
Cheers
Thanks very much for that Van Halen.
Incredibly helpful.
May I ask wtf is type 3?
I don't really want too much gravel if it can be helped, as I don't want to feel like I'm driving across Brighton beach every time I use it?.
Plus the stuff scatters everywhere. Have you considered slate chippings ? It tends to remain exactly where you put it. I have no idea how its drainage qualities compares with gravel but I can't imagine that it's that bad.
Type 3 has less dust/fines in it so it won't block drainage.
My neighbours gravel drive appears to be relocating across down the road outside our house.
Type 1,2&3 are aggregates defined by their grading. The idea is you know what the material properties are and how therefore how it will perform. Type 1 and 2 are aggregates with fines. type 3 is a low fines aggregate often used in permeable paving applications.
Oh if it's on a slope you may want to look at a cellular geogrid instead of sub base to stop the gravel washing out.
It's pretty flat so shouldn't need geogrid.
Just had a rough work out. Seems we need 12.5 tonnes of hardcore!
Any idea roughly how much that would cost?
I was humouring you but you know that don't you 😉
Good luck on getting a price on "type 3"
If you want hardcore just get recycled 6f bang it down and top with 50mm of your selected gravel. Any of these options is a bit Heath to be fair.
Prob as cheap if not cheaper to get 20t dropped, 1t bags will get expensive, you cod prob get it for £10 to £15 a ton locally if you call around and are flexible on when its dropped
Go easy on the depth. My drive is like chesil beach after a 20 tonne load of new gravel on top of my recently scraped base. Took me a weekend to spread it with a 7t digger and then drove the van on it and it just stopped. Back to the drawing board, another weekend scraping material off a few bags now full of "spare" gravel and it's fine. I put approx 10 cm down originally but iirc 2 cm will do....