On the exterior flooring market, the success of gravelled slabs is undeniable. It is explained by the many qualities of this solid material, practical, economical and easy to install. Despite some drawbacks, the gravel slab deserves a presentation: discover its “pluses” and “minuses”… and the technique for laying them in your garden.
The gravelled slab, an invention that makes life easier.
Since the time you want to redo your old terrace, or build a beautiful garden path… Do you lack the time, or the money, or both? Rejoice: the gravel slab was invented for you!
This concrete slab sprinkled with exposed gravel was designed to dress an outdoor floor like a tile. Cheap and quick to install, it is also appreciated for its rough and non-slip side.
You can find two types of gravelled slabs on the market:
- A gravel slab in deactivated concrete, to be used for large surfaces. It has the advantage of being customizable and the disadvantage of being heavy and difficult to handle.
- Give it de type prefabricated is easier to use. It arises everywhere, with the exception of vehicle areas. Its problem is that it does not resist the passage of vehicles…
The gravel slabs come in the form of tiles, generally 40 or 50 centimeters on a side. They adapt to most outdoor flooring needs: swimming pool border, garden path (but not garage) or terrace. Not only is the paving site quick and easy, but the paved area will also be easier to maintain.
Concrete gravel slabs: 10 advantages
What explains the success of gravelled slabs? Here is a list of the (many) qualities of this off-road coating.
- Solid and durable. Able to withstand years and shocks without splitting or breaking.
- Weather resistant. Neither the rain nor the frost nor the heat overcome it.
- Aestheticsif you appreciate their natural appearance which blends easily into any decor.
- Varied. Depending on your tastes, you can play with the colors and size of the gravel.
- Non-slip. Which is very practical around a swimming pool, for example.
- Versatile. As we have already said, gravel slabs can be used for edging a swimming pool as well as for creating garden paths or renovating a terrace.
- Cheap. No need to break the bank for a beautiful driveway. To dress a terrace, gravel slabs offer one of the best value for money on the market (significantly cheaper than natural stone, for example).
- Easy to lay. Anything easy to do, we like.
- Economical in works. No need to rent or buy large equipment. The project is relatively simple to carry out; you probably already have most of the tools…
- Simple maintenance. Especially the slabs with small gravel, which are easier to clean.
Gravel slabs also have disadvantages…
While gravelled slabs have many advantages, this does not prevent some of their limitations from being raised.
- Side aestheticthe most demanding of you will regret a limited offer in colors and shades. The most frequently offered colors are black, white, pink, beige and gray. Let’s face it, the effect of gravel slabs cannot be compared to the elegance of natural stone or wood… It’s a coating that lacks a bit of fantasy.
- The coarsest gravelled slabs should be avoided if possible. The large gravel have several disadvantages: they hurt your feet when you walk on them without shoes (too bad for the pool exit) and are more difficult to clean. You will have to take out the pressure washer. Unfortunately, small gravel is more expensive than large ones…
- In some cases, especially for a garden path, the installation requires a soil preparation. Plan to create a bed of sand in order to lay the slabs flat.
To lay gravel slabs: 2 techniques
The technique chosen depends on the project and the type of slab. For a garden path, it will first be necessary to make a bed of sand. Especially if you are using precast type slabs. Deactivated concrete slabs are laid with a concrete pour. On a concrete slab, the gravel tiles, after laying, will be sealed with mortar.
Lay gravel slabs on a concrete slab
Do you want to redo the terrace? For this kind of renovation, start with a thorough cleaning of the slabs and the screed. The gravel slabs must be cleaned thoroughly and on each side. As for the screed, lay it bare and also clean it thoroughly. The gravel slabs are then laid and sealed with mortar.
Install your gravel slabs on a bed of sand
To create a flat and stable garden path, follow these steps:
- Measure et delimit the perimeter of the driveway. After taking the measurements, plant stakes and tie them with string to clearly visualize the space to be paved.
- Dig the ground inside the perimeter, 10 to 15 centimeters deep. Your driveway should not overhang the lawn (that would be ugly). This disbursement is essential to bring it up to standard.
- Tamp the soil well over the entire surface to be paving, using a wide, flat pestle.
- Then run a movie geotextile, which will protect your driveway from the growth of invasive weeds between the slabs. The film must be adjusted to the perimeter; if necessary, cut the excess.
- Cover the geotextile with sable over the entire surface. Tamp the sand with the pestle. Equalize the level.
- Lay the tiles, one row after the other, leaving a centimeter of space between each. Always start at an angle.
- feel free to stabiliser gravel slabs using a rubber mallet.
- At each slab, check its horizontality with a spirit level, in case it is slightly tilted. In this case, correct the position with a mallet. Always level to make sure the tiles are aligned with each other.
- If a slab must protrude from the driveway, cutcut it to the right size with a grinder, which you will have equipped with a disc for stone.
- When all the tiles are laid, pour some sable above to fill the joints. Then pass the broom to clean the overflow of sand.
What budget should I plan for laying gravel slabs?
The price changes according to the type of slab. Precast slabs are about half the price of deactivated concrete slabs. Although the price depends a lot on the fineness of the gravel…
- Slabs prefabricated found in stores come in standard sizes of 50 x 50 or 40 x 40 centimeters. Their thickness varies from 35 to 42 millimeters. The coarser they are, the less expensive they are. A coarse gravel slab costs 2 euros, while with fine gravel it will be more than 5 euros per unit. Count a little over 10 euros per square meter with coarse gravel; as for fine gravel, it is more like 35 euros per square meter.
- The slabs in concrete disabled are around 25 euros per square meter.
- The tools of installation are rather cheap. The main investment is the geotextile film, which costs around 25 euros per meter. Better to rent or borrow the manual lady (the pestle) and the diamond disc grinder for stone. For the rest, you need a shovel, string, stakes, a mallet, a meter, enough to make cleats. The sand costs around 6 euros per kilo.