How to lay natural stone pavers?
Do you want to landscape a driveway, a garden path, or a terrace with natural stone pavers? With a little skill and good preparation, you can achieve an aesthetic and durable installation yourself.
In this article, discover the essential steps for laying natural stone pavers, with 3 main techniques: laying on a gravel bed, laying on a draining screed (draining mortar), and glued laying on concrete.
First Step: A Solid Base
Before beginning the paver installation, it's crucial to ensure solid foundations to prevent any settling or movement of the pavers over time. Excavation is a key step in this preparation.
1. Ground Preparation
The first step is to prepare the ground. The surface should be backfilled with compacted hardcore, depending on the soil quality. Then, a layer of 20 to 40 cm of 0/40 stabilizing gravel, well compacted, should be added, depending on the terrain conditions. If necessary, it is advisable to consult a professional to ensure proper soil preparation.
2. Foundation Depth
- For a surface subjected to heavy loads (e.g., a drivable driveway): allow for a depth of 40 cm.
- For a pedestrian area (such as a garden path or a terrace): 20 to 30 cm is sufficient.
3. Soil Compaction
After excavation, the soil must be compacted using a vibrating plate to ensure good stability and properly prepare the base before laying the pavers.
There are 3 main methods for laying natural stone pavers:
Method 1: Laying on a Gravel Bed
The dry laying method is simple to carry out and allows for good water drainage. It involves laying the pavers directly on a layer of gravel, which ensures optimal drainage.
Although this method is simple and quick to implement, it offers less stability than other techniques, as it does not rely on a cement bond. This can lead to weakening of the structure in the long term and make the pavers less durable against bad weather or heavy loads.
On a 3/6 aggregate layer of about 5 cm
This method uses only 3/6 aggregate, applied in a layer of about 5 cm. For pavers of constant thickness, the layer is leveled with a screed. For pavers of variable thickness, each paver is laid individually and tapped with a mallet to adjust it correctly.
Laying Steps:
-
Delimiting the Surface: Mark the paver location with strings to define the area to be landscaped.
-
Excavation and Compaction: Remove soil to a depth of approximately 10 to 12 cm and compact the ground with a vibrating plate to ensure good stability.
-
Placing the Gravel Layer: Lay a 3/6 gravel layer of approximately 5 cm and compact it with a vibrating plate to ensure a solid and stable base.
-
Adding a Layer of Sand or Laying Gravel: Add approximately 5 cm of sand or laying gravel to adjust the height of the pavers and obtain a flat surface.
-
Laying the Pavers: Start with the edges, secured with a lean concrete support, then lay the pavers one by one, tapping them with a mallet to level them.
-
Final Compaction: Use the vibrating plate to stabilize the pavers and ensure their fixation.
- Joint Filling: Joint filling varies depending on the chosen method (sand, mortar, or polymer). Follow the specific instructions below for each method to ensure proper filling and prevent movement or water infiltration.
Method 2: Laying on a Draining Mortar Layer
This method involves using a mixture of 3/6 aggregate and cement to create a draining mortar. The mortar layer, about 6 to 7 cm thick, is applied and leveled with a screed for pavers of constant thickness. For pavers of variable thickness, each paver is laid piece by piece and tapped with a mallet to ensure a good fit on the loose mortar.
Advantages:
-
Enhanced stability and adhesion: Draining mortar offers better stability than laying on a gravel bed, especially for pavers of variable thickness.
-
Increased durability: This method is more durable, as it creates a solid bond between the pavers and the ground.
-
Effective drainage: Draining mortar allows water to flow easily, which is an advantage for outdoor applications.
Laying Steps:
-
Delimiting the surface: Mark the paver location with strings to define the area to be landscaped.
-
Excavation and compaction: Remove soil to a depth of approximately 10 to 12 cm and compact the ground with a vibrating plate to ensure good stability.
-
Placing the mortar layer: Prepare a mixture of 3/6 aggregate and cement (300 kg of cement per m³ of aggregate) and lay a mortar layer of approximately 6 to 7 cm thick. Level the layer with a screed to ensure a flat surface.
-
Laying the pavers: For pavers of constant thickness, lay them directly on the mortar layer, adjusting them to level. For pavers of variable thickness, lay them piece by piece and tap each paver with a mallet for optimal adjustment.
-
Final compaction: Use the vibrating plate to stabilize the pavers and ensure their fixation.
-
Joint Filling: Joint filling varies depending on the chosen method (sand, mortar, or polymer). Follow the specific instructions below for each method to ensure proper filling and prevent movement or water infiltration.
Method 3: Glued Laying on Concrete Slab
The glued laying method on a concrete slab involves applying an adhesive mortar specifically designed for fixing pavers to a concrete slab. This method is particularly suitable for surfaces such as terraces, drivable driveways, or pedestrian areas where strong adhesion is necessary. The adhesive mortar is applied directly to the concrete slab, and then the pavers are laid on top, ensuring a solid and durable fixation.
Advantages:
-
Enhanced adhesion: The adhesive mortar ensures excellent adhesion between the pavers and the concrete slab, which allows for a stable and durable installation.
-
Increased stability and resistance: This method is particularly suitable for areas subjected to heavy traffic or harsh weather conditions, thus offering strong resistance.
- Speed of installation: Glued laying allows for working on a clean and smooth surface, which facilitates and speeds up installation.
Laying Steps:
-
Concrete surface preparation:
Ensure the concrete slab is clean, dry, and free of any dust or dirt. If necessary, clean the surface with a brush or vacuum cleaner.
-
Adhesive mortar application:
Prepare the adhesive mortar according to the manufacturer's recommendations. Apply a uniform layer of adhesive mortar to the concrete slab surface using a notched trowel. This layer should be thick enough to ensure good adhesion.
-
Laying the pavers:
Lay the pavers one by one on the adhesive mortar, adjusting them to be well aligned and level. Use a rubber mallet to gently tap the pavers and secure them firmly into the mortar.
-
Final compaction (if necessary):
If the product allows, you can use a vibrating plate to stabilize the pavers. However, it is important to ensure that the surface is smooth and free of deformation before proceeding.
- Joint Filling: Joint filling varies depending on the chosen method (sand, mortar, or polymer). Follow the specific instructions below for each method to ensure proper filling and prevent movement or water infiltration.
How to fill the joints between the pavers?
There are 3 main methods for jointing pavers:
Method 1: With sand or 1/3 mm aggregate
This method is very economical and easy to implement. It consists of using sand or 1/3 mm aggregate to fill the joints between the pavers. No special tools are required, and no particular technical skills are needed, making it a simple and quick solution to apply. It is therefore an excellent option for those looking for an affordable and fast method to execute.
However, it has some drawbacks. The sand or aggregate can shift due to bad weather or on slopes, which can lead to premature wear of the joints. Moreover, this type of joint allows weeds to grow easily, requiring regular maintenance to maintain the appearance and stability of the installation.
Method 2: With cement-based mortar
This method, which uses a mixture of 0/3 sieved sand and cement (300 kg/m³), offers good value for money. It is advisable to use a pozzolan-based trassiment, such as that offered by Minéral, to strengthen the joint's solidity and prevent subsidence.
At Minéral, instead of using a cement and sand-based mortar, we favor Murexin SF 50 mortar. SF 50 washes better than traditional mortar, has less risk of cracking, and is easier to apply. Moreover, it allows for joints up to 50 mm wide, which makes it particularly suitable for various applications. This is why it is widely used by many professionals.
The SF 50 is applied in liquid form into the joints, which improves the locking of the pavers. After application, excess material should be scraped off with a squeegee and the mortar applied to the paver should be lightly watered. Once the paver is watered, the joint will no longer harden, leaving you enough time to easily clean the surface with a sponge or a water jet, thus ensuring a beautiful finish.
This technique is durable over time, but small cracks must be accepted, especially when pavers are laid on aggregates. However, these cracks remain barely visible on the pavers.
Method 3: Polymer joint
Polymer joint is a more expensive solution, but it offers numerous advantages. Easy to apply, simply sweep it into the joints and moisten it. It hardens within 24 hours, providing a neat and durable finish. This product is permeable, allowing water to drain naturally without retaining moisture, an essential asset for outdoor applications. It also masks small cracks caused by ground movement, thus ensuring a uniform appearance.
However, its relatively high cost can be a barrier for some projects. Furthermore, it should not be used when laying concrete slabs, as this could impair its effectiveness. The PCIPavifix product, offered by Minéral, is an example of this type of solution.
Laying patterns and finishes
Natural stone pavers allow for the creation of various patterns:
Straight lay: simple and quick.
Circular lay: ideal for terraces and decorative areas.
Arch lay: provides a dynamic and aesthetic appearance.
To hire a professional or do it yourself?
If you have a small area to landscape with a simple pattern, the installation can be carried out by a skilled DIY enthusiast. However, for large areas or complex patterns, the expertise of a professional guarantees an optimal result.
Note: all indications given are for informational purposes only and do not replace the recommendations of a building expert.
With these tips, you are ready to enhance your outdoor spaces with natural stone pavers!
