If you’re thinking of laying a new patio then this article should help ensure you get strong, level foundations for your pavers.
You can use gravel as a paver base as it performs the same function as paver base itself. While paver base is coarser and locks together more tightly than gravel, they are both used to form a thick layer over your landscape fabric which is then covered with sand that you lay the pavers on.
Is Paver Base The Same as Gravel?
In short, yes it is. However, paver base isn’t the aesthetically pleasing gravel you use for your driveway or pot plants. It’s a coarser aggregate, generally made from local rock (coarse gravel comes from whatever rock is readily available).
It’s also known as road-bed gravel or sometimes crusher rock. Your supplier may also refer to it as “¾ minus gravel”, as that tends to be the size of the largest pieces (in inches), although you can get larger 1 ½ inch gravel as well.
Obviously, this rough-looking stone is going to be cheaper than an ornamental gravel. However, its unfinished quality is its main advantage. Those rough edges and random shapes lock together, creating a solid base (smooth gravel won’t lock together this).
You can also pick up recycled gravel, which is a cost-effective and environmentally friendly version, often made from crushed-up used concrete. Builders’ sand is another alternative to paver base gravel.
Some home builders say you don’t need to use gravel under pavers, and for simple jobs, you can just lay them straight on the earth. This sounds pretty high-risk to us: how do you know that the ground will stay stable and even?
It’s not expensive or difficult to use a proper gravel paver base before laying the slabs. Without gravel, you also may be running the risk of destabilizing your ground’s natural drainage properties (or in some cases, lack of).
What Size Gravel Should I Use?
There are broadly three sizes of paver base gravel: fine, medium and coarse. Which one you use depends on your project: a fire pit will need a different type of gravel to your driveway, for example.
Fine gravel is close to builders’ sand, and is perfect if you have sandy or well-drained ground. It compresses into a solid base, so we don’t recommend it unless you already have good drainage, as it really doesn’t drain well.
It’s also only suitable for lighter use: great for domestic garden use (under your fire pit, barbecue or garden furniture, for example), but it’s not the right base to go under driveways or parking areas. Expect the gravel pieces to measure around ⅜ of an inch.
Medium gravel is a good general choice, providing you with both strength and drainage. It compresses neatly, but still allows water to pass through it. It will take some traffic (such as the weight of a regular car), but because it’s suitable for lots of ground types, is also used for the lighter domestic jobs we mentioned above. This popular gravel is made up from pieces up to ¾ of an inch (hence the “¾ minus gravel” name).
For heavier duty use, play it safe and order in coarse gravel. If you have poor drainage (clay soil, for instance, provides very little drainage) or want to build a driveway for multiple cars, this is by far the best and safest option.
We’d also suggest using coarse gravel under your pavers if you experience heavy rainfall where you live, or if you have problems with runoff water. The typical pieces measure 1 ½ inches: you can get bigger, but super-heavy gravel generally isn’t used for yard paver projects.
So, before you order your supplies, think about your projects, the type of soil you have, and how you will be using your paved area.
How Thick Should The Gravel Layer Be?
Again, this depends on your application, as something like a heavy-traffic driveway will need tougher foundations than a low-footfall walkway. And (yes, we’re saying this a lot), different soils behave differently, and you may need to compensate for inadequate natural drainage.
We’ll look at the anatomy of the paver base in more detail later, but here are the basic rules for gravel layers.
Most experts suggest at least 4 inches for the gravel or crushed stone layer, then an extra inch for a layer of sand. We’ve always gone for at least 6 inches for the gravel layer: yes, it’s a bit more digging, but we reckon it’s worth the effort for that extra peace of mind. For driveways, some builders insist on digging down a foot, ensuring that you have one tough and reliable paver base layer.
Of course, the local dirt has as big a part to play in paver construction as the actual application itself. If you live in one of the rainier states or have clay soil, the deeper the drainage layer, the better.
Even if you’re lucky enough to live in a dry or temperate climate, it’s wise to overcompensate when it comes to drainage. You may experience a burst water main, flash flood or unexpected runoff, and it’s best to be prepared (sorry if this doesn’t sound very cheerful; however, we want to protect your yard against any future problems).
Once you’ve decided on the depth of gravel you need, it’s a simple calculation (depth times surface area) to decide how much paver gravel you need to order. Our usual rule is to add 10% on top of that as a contingency – you may need it, and if you don’t, gravel rarely goes to waste in the busy gardener’s world.
The Anatomy of a Patio Base
We’ve spoken about layers under your pavers, but what exactly are they, and what does each layer bring to the construction? From the dirt up, here’s the anatomy of your new driveway or garden dining area.
Excavate to your chosen depth, then on top of the soil, the first thing to introduce is the layer of landscape fabric. This can be a plastic membrane or a woven textile, and it has the job of protecting your construction from plants growing upwards. This layer has to be permeable to allow for drainage, and choose a heavier duty material than you would use for light gardening duties.
Then, we have the thickest section, the gravel layer. Gravel really is the ideal material for your paver base, as it is strong and durable, compresses to form a tough layer, and as we’ve already discussed, ideal for drainage. Choose your typeof gravel based on soil type and your application.
On top of the gravel, we add a layer of coarse sand. This forms a smooth, level layer on top of the gravel, which is used as a bed for your pavers. Most builders recommend that this layer should be an inch thick. Moisten it and tamp it down to form a solid layer, ready for laying the final pavers. And finally, we come to the best bit: your choice of pavers, which come in a great range of colors and textures.
We should also mention that there’s a new alternative to a gravel base. Some builders don’t use this traditional anatomy, replacing the gravel layer with plastic paver panel. They have grooves for drainage, and are said to be ideal for areas prone to hard frosts, as they are insulating. So, if you use this, your layers will be: dirt, fabric, sand, paver panel, paver.
Similar in function in the context of laying a patio, you can indeed use gravel as a base when laying your pavers. Just like the coarser paver base itself, gravel can be successfully used to create a thick layer over the top of your landscape fabric – before the sand layer and pavers are laid on top.
The only significant difference between gravel and paver base, is that the sharper edges of paver base mean it can lock together more effectively than gravel when packed down under the sand and pavers. However, this does not negate the use of gravel if you tamp it down well enough.