Is Gravel Suitable on a Sloping Driveway?
I'm building a house and would ideally like a gravel driveway to fit in with the rural location. However, the drive will have a 1:12 slope, and I suspect this would mean gravel is impractical. I don't like concrete or tarmac particularly, and any block paving would need to avoid looking "suburban". Are there any other options that would work on a slope such as mine?
You're absolutely right, gravel will be impractical for a drive with a slope like that. Quite apart from the constant topping up that you'd need to do, because the gravel will naturally roll downhill when someone drives over it and whenever it rains hard, there be a health and safety aspect. Shoes would sink into a thick layer of gravel, which would be more likely to stay in place on a 1:12 slope, and a thin layer would roll on the supporting bed of concrete or other hardstanding.
Both would be very tricky for people to walk on, particularly the elderly, and in some circumstances you might even have trouble getting traction in a vehicle.
However, it is quite understandable to want to avoid the 'suburban' look of Block Paving. The good news is that there are a couple of ideas that could work and give you the look you're after.
Try Small, Rounded CobblesFirst, you could try setting small cobbles into a concrete substrate, a technique that's covered in our 'Loose Materials' section (see Advice on Hoggin, Cinders and Ash Driveways). If you chose small, rounded cobbles, you’d get close to the look of gravel. But the aggregate would be set in the bedding layer, so it wouldn’t be off down the hill at the first opportunity.
It can be uncomfortable to walk on though, so you might consider gravel or paving stones for the paths leading from the house to the drive.
Cellular MatsThe second option would be to look at some of the newer cellular supporting structures for drives. Again we've covered these on the site (see Cellular Paving Systems For Your Driveway) but focusing on their use as a material that will allow grass to grow through them. The good news is that you can use these cellular mats with the cells filled up with gravel instead of letting grass grow through them.
On a 1:12 slope, you would almost certainly still lose gravel to some extent, so occasional topping up would be necessary. This will be particularly so after a six-month bedding-in phase, as the gravel compacts in the cells. But after that it should work well. An edging course might be a good idea, as that would restrain any gravel that escapes from the cells.
Get the Colour and Substrate RightChoose a cellular mat that's as close in colour as you can get to the gravel you are using, so that if it does start to poke through as the gravel compresses it won’t be so obvious.
Also talk to the supplier or manufacturer of the mat about what layers, either membranes or substrates, to put down underneath it. You'll need to ensure that the mats will stay in place on that slope and that gravel isn't compressed straight through into the soil below to disappear.