The best ways to stop gravel moving off a driveway
Driveways are not just practical aspects of a house, providing somewhere to keep cars off the road and close to hand – they also form an important part of the overall kerb appeal of a property. As such, everything from size to drainage requirements need to be taken into account if this is a space that will do justice to the exterior of your home.
In the case of my own drive, I chose the driveway materials purely for their aesthetics – the buff-coloured Cotswold stone gravel seemed to fit in nicely with our cottage, as well as its rural surroundings. What I did not realise was how hard it would be to keep this gravel in place. As it is, it somehow leaches out onto the pavement and into the road – something that looks really messy if not regularly dealt with.
While sweeping it back to where it is supposed to be provides a temporary fix, I’m really keen to find out where we went wrong in the first place and whether or not there is a solution we could implement now. I reached out to the experts to ask for their top tips on keeping gravel in place on a driveway and they offered five effective solutions to solve the issue.
1. You need to start with a good sub-base
This first step is really important – in reality, the success of any driveway, whatever materials it is finished with, relies on the right initial preparation work. In fact, one of the biggest driveway mistakes is to fail to give enough consideration to installing a proper sub-base.
When it comes to gravel driveways, you want to create a stable, well-compacted base, at least 100-150mm deep, using either type 1 aggregate or crushed stone. This will act to give support to the gravel you subsequently put down and help to prevent it from moving around too much.
The experts I spoke to were also keen to point out that it is also wise to it lay a separation membrane between the base and gravel in order to stop the gravel and soil mixing – particularly in wet weather.
2. Gravel shape matters more than you think
I have to admit, I gave very little thought to the shape of my gravel – I just liked the creamy colour. However, apparently, if I had, I might not now be locked in a constant battle to keep it in place.
Guy Wall, head of marketing at GCL Products explains why shape matters. “Angular gravel locks together better, unlike rounded pea gravel. Imagine a Scrabble bag which you put a handful of stone inside and try to manipulate and move around in your hand through the bag. Angular gravel locks together and is relatively difficult to get much movement out of. Now imagine it filled with marbles and the result is very different. The rounded shape happily glances off other pieces without any or very little interlocking between pieces. This is the same for the stone on your driveway. Rounded stone wants to roll away. Angular gravel doesn’t roll.”
And your gravel driveway ideas should not just come down to shape – size plays a part too according to Guy. “The size matters, as finer grades of gravel can become easily stuck in tyre treads or, if you have very fine gravel, even shoe treads.
“If you have gravel grids, go too large with your gravel and you’ll find that the stones can break the internal walls on the grids,” continues Guy. “We normally recommend using a grade which is suitably sized according to the cell dimensions. For example with the X-Grid from GCL, the circular cells are 55mm diameter, so we recommend stones of no larger than 20mm diameter. This means that any two pieces of stone should easily fit next to each other without causing stress or strain on the cell walls.”
Guy has extensive knowledge on sustainable drainage, gardens and landscaping as well as some interest and experience in solar and renewable technology. Resin bound gravel, wet pour rubber surfacing and permeable surfacing are his specialities.
3. Using the right height edging is crucial
However, due to us completing the driveway before we started on the extension and renovation of the house, what ensued was a barrage of delivery lorries which not only managed to knock down our newly installed gate posts, but, because of their weight, ended up sinking the edging we had put in place.
It now needs rebuilding as this would make a huge difference in how well-contained the gravel is, but this time we’ll be paying more attention to its design, particularly its height. Having spoken to the experts it should sit just above the top of the gravel but not be so high as to cause a trip hazard.
4. Consider the depth of the gravel
Again, not an element of driveway design that I gave too much thought to – I just assumed that I’d need enough gravel to cover the base rather than researching recommended depths.
“Loose gravel drives are great. They’re natural, help to reduce hydrocarbons as a source control measure and come in so many different colours, grades and shapes that you can easily find one that meets your needs perfectly,” picks up Guy Wall. “However, it’s not just a case of dig a hole and fill with gravel, unfortunately.
“Depending on the depth of your gravel, you can find that the gravel seems to want to escape its confines and take up home elsewhere,” continues Guy. “Certain depths can actually cause your car to get ‘beached’, where the underside of the vehicle is either partially or fully resting on the surface with the tyres unable to get traction, meaning you’ll need to reach for the shovel.”
Apparently, when making modifications to tame my gravel, I should be aiming for a depth of between 40-50mm.
5. Gravel grids are the perfect way to hold everything in place
I so wish I had realised how effective gravel grids were in holding everything in place. Had I investigated how to lay a gravel driveway properly and installed one from the off, things would be looking very different outside my house right now.
“Gravel grids are a relatively new but highly efficient invention. Their sole purpose is to retain the gravel, prevent migration and also give some strength and stability to the surface,” explains Guy Wall. “By locking small amounts of stone inside the cells of the grid, the pockets effectively trap the gravel and prevent it from migrating to other areas nearby.
“Different grids may have different shapes or patterns in them and come in different shapes, sizes and weight tolerances,” continues Guy. “In 99% of cases, using any gravel grid is better than using none on a surface trafficked by vehicles, however, not all grid products are manufactured or designed equally.”
Given that we plan on making some significant alterations to our driveway in the coming year in order to give our home an exterior makeover and make it possible to get another car in by applying for dropped kerb planning permission, I am keen to use a grid this time around – so I asked Guy what I should look out for when choosing one.
“One of the most important things to consider is: is it made for this purpose?” begins Guy. “We have seen several products being used which weren’t purpose-designed for gravel retention and had other uses such as pond safety grids. These typically have large diamond shape cells in the body of the grid and, honestly speaking, they didn’t work particularly well. The cell size was far too large, the plastic far too thin and low quality, so not only did they break but the gravel still migrated.”
Instead, Guy suggests something like the X-Grid from GCL Products which is made from a specially formulated polymer to make it very hard and durable and also has enough flex to cope with heavy loads across surfaces which may not be completely flat.
“The cells are a combination of asymmetric shapes and circular columns to help dissipate vertical loading pressures laterally, meaning it has load-bearing credentials of a proven 428 tonnes of vertical load per square metre, before even being filled,” adds Guy.
FAQs
How should you maintain a gravel driveway?
While all the above methods should help keep gravel where you want it, there are steps you can take on a regular basis in order to help too.
Raking the gravel to ensure it stays evenly distributed will help a lot, as will topping up bare patches with a more angular gravel in order to keep the depth as it should be.
When designing your driveway, don’t forget the importance of good driveway drainage measures – not only will they ensure your driveway stays looking great, but they are also a Building Regulations requirement.