Laying techniques >

1. Foreword
2. Laying paving on soil
3. Laying paving on sand
4. Laying paving on concrete(1) (2)

4. Laying paving on concrete (part 1)

Description

In light of the loads they must support, patios and driveways must be supported by sufficiently stable and robust foundations. This is why it is strongly recommended to pour a concrete slab on which your paving will then be laid. The concrete slab will itself be poured over a layer of crushed stone or rubble to ensure its stability and enable natural water drainage. On normal ground, a thickness of 5cm will be sufficient. However, if the ground is loose or if the paved area will have to support heavy loads (trucks), you will need to increase the thickness of the concrete slab or reinforce it with a welded steel frame. To avoid cracks in the concrete, it is important to include expansion joints when surfaces are greater than 30m².

In pictures

1. 

   Dig a trench slightly wider than the paved area, to a depth of approximately 8" to 10" (20 to 25 cm).

2. 

   Fill the bottom with rubble, making it as even as possible.

3. 

   Soak the rubble with water and tamp it down with a tamper.

4. 

   To pad out the stones, cover with a layer of mixed grade sand (mixed sand and gravel).

5. 

   Use mortar to seal battens along the sides of the paved area; ensure they are positioned at the exact height of the concrete slab and take into account the slope required.

6. 

   Separate the surface to lay into approximately 20 foot (6 m) sections using oiled planks; once the concrete has dried they will be withdrawn and the expansion joints will be released.

4. Laying paving on concrete (part 2)

Description

Use concrete that contains one part cement to 3 parts aggregates; a concrete mixer will of course be needed if the surface is extensive. Once the concrete is dry (48 hours), you just need to lay the paving stones on a thin layer of cement mortar. It is recommended to add 20% of pozzolana in the fixing mortar to give it better elasticity and avoid the formation of cracks which risk compromising the durability of the paving. Another technique consists in laying a thin layer of sand between the concrete and the fixing mortar. A precaution to remember: wet the stones generously before laying them on the mortar, otherwise, the stone will come unstuck after a certain amount of time.

In pictures

1. 

   Prepare the concrete, using a blend of one part cement to 3 parts aggregates.

2. 

   Pour the concrete in the trench and spread it out up to the level defined by the lateral guide battens.

3. 

   Level off the concrete using a wooden plank resting on the guide battens.

4. 

   After 48 hours, wet the concrete then lay a thin layer of fixing mortar about 0.4" to 0.8" (1 to 2 cm) thick.

5. 

   Humidify the paving stones and lay them on the fresh mortar.

6. 

   Fix the stones at the right level using a wooden plank and a mallet. Ensure you include a slight slope for water run-off.

Did you know?

Sedimentary rocks are the result of the accumulation and compacting of mineral debris (i.e. other stones), organic debris (animal remains and vegetation, fossils), or chemical precipitation.

They are exogenous rocks, i.e. rocks are formed on the surface of the Earth. Sedimentary rocks are present on 75% of the surface of the Earth's continents, but when considering its crust as a whole (from the surface to a depth of 22 miles (35 km)), they only represent 5% of its total volume.

The main sedimentary rocks are:

• sandstone
• sand
• siltstone
• loess
• clay
• shale
• coal
• oil
• limestone
• chalk
• etc.

SOURCE: Wikipedia