Laying terrace slabs on concrete is rarely recommended, because the slabs are easier to lay on an unbound subsurface. In addition, water drainage is ensured. However, application to concrete is also possible.

In a nutshell

  • There are four different options for laying the panels
  • the water drainage must be ensured in any case
  • Which method is optimal depends on the local conditions
  • Expansion joints should be considered
  • for tenants there are also systems that can be easily dismantled and reused

preparation

Anyone who rents a house or apartment and already has a concrete area available as a terrace usually cannot simply tear it down. However, this is usually not necessary, because the terrace slabs can also be laid on the concrete with the right preparation. The following preparatory steps are necessary for this:

1st slope: First of all, it must be checked whether the concrete surface can ensure efficient water drainage. Depending on the type of panel selected, the surface should have a gradient of two to three percent. If this is not the case, a slope with drainage concrete must first be created. When the layer has dried, the slope should be checked again.

2.Expansion Joints: In order to apply the chosen type of board, expansion joints should be marked. If these are already present in the concrete surface, they can be used as orientation when laying. The joints also support the drainage of water.

3.Cleaning: In order to achieve optimal results, the concrete surface should be thoroughly cleaned before the terrace slabs or the underlying layer is applied. Sweeping is sufficient for light and dry soiling. For heavier soiling, a sandblaster or a Kärcher should be used to create a clean surface.

4.Insulation and Insulation: If there is a living room, cellar or garage under the concrete layer, additional insulation can be useful. In advance, however, it must be checked whether the underlying roof can safely bear the weight of concrete, slabs and additional materials.

5.Method: Depending on the method chosen, different tools will be required, which should be ready before starting work.

On grit

A simple and inexpensive way of laying is to use chippings. With this guide, all you need to do is follow these simple steps:
If necessary, first provide the edges of the concrete surface with metal rails, which should protrude at least four centimeters at the top end. These form a framework and prevent the chippings from spreading outside the concrete surface.
The chippings must be applied at least three centimeters thick and can also be used to level the slope. The water can still drain off the bonded surface through the planned joints. For this purpose, water drains should be planned on the sloping side.
The panels can now be placed on the grit bed. It is imperative that the correct distances are observed to ensure that the water drains away. The insertion of joint rails makes this work easier and offers protection for the concrete and the terrace slabs.

On pedestals

Laying the slabs on so-called pedestals is extremely easy and has the advantage that both the brackets and the slabs can be very easily removed and reused. If you live for rent, you can not only save work and effort, but also money.
Pedestals are - usually height-adjustable - brackets that are screwed to the concrete floor. A drill with the appropriate attachments is therefore required for fixing. After that, this handy guide will do the following:

  1. Depending on the size of the slab, the brackets are fixed to the concrete surface at regular intervals.
  2. In order to achieve a level surface or the required gradient of two to three percent, the heights of the individual pedestals must be precisely coordinated with height-adjustable variants. A folding rule is usually the best choice for this. In addition, however, a spirit level can also be used in order to be able to better coordinate parallel pedestals
  3. When setting and fixing the pedestal, care must be taken to ensure that the center pieces between the panels, edge and corner pieces are at the correct distance from one another.
  4. If all pedestals are in the correct position, the terrace slabs are simply placed and pressed.

Tip: Another advantage of pedestals is that they automatically create a gap between the concrete surface and the floor slabs. This allows the water to drain away unhindered. In addition, there are height-adjustable models on the market that can be used to make optimal adjustments. Furthermore, the application of additional drainage concrete to create a slope can be saved, which is a clear advantage in terms of costs, time and effort.

With stone glue

Drainage concrete can be used as a stone adhesive for a particularly durable and firm attachment of the floor slabs on the terrace. Standard concrete is not recommended, as damage from water and frost can occur here. The following instructions show what needs to be considered.

  1. Lay drainage rails for orientation to ensure water drainage and to be able to align the floor panels more quickly and safely.
  2. Mix the drainage concrete and allow to thicken. Observe the information provided by the manufacturer.
  3. Apply the drainage concrete between the rails with a mason's trowel. Only ever use and apply as much of the wet mass that two to four panels can be laid on it. Because only a thin layer is applied, it dries comparatively quickly and hardens in the process. This can reduce the durability of the stone adhesive.
  4. After the stones have been laid, a spirit level should be used to check whether they are level. Otherwise, individual slabs on the terrace can become a tripping hazard. The check should take place when the drainage concrete or stone adhesive is still damp and malleable in order to be able to make any necessary corrections more easily.

On paddock plates

The main purpose of paddock slabs is when keeping horses as a reinforcement of lawns or meadows. However, they can also serve as a base for floor slabs, as they create a gap between the concrete base and the slabs themselves.
Since they are mostly made of flexible materials, they withstand pressure well and act as insulation against bumps and kicks. However, attaching the paddock panels and the floor panels to them is more difficult. A combination of pedestals and paddock slabs can therefore be ideal. The paddock slabs act as insulation, while the pedestals provide the necessary support on the concrete floor. The following guide shows how this combination works:

  1. The terrace is thoroughly cleaned.
  2. The pedestals are placed on the terrace at regular intervals so that the corners of the floor slabs can be fixed in them.
  3. After the paddock slabs have been fixed, the terrace slabs can be laid as described in the other examples.

frequently asked Questions

How can patio tiles and joints be cleaned?

If the floor slabs are on a concrete substructure and attention is paid to both water drainage and sufficient expansion joints, cleaning is correspondingly easy. Stone slabs on the terrace can be cleaned very easily with a Kärcher. Difficult soiling, such as moss or dirt that has entered, can also be removed relatively easily with this device from rough surfaces.

How wide should the expansion gaps be between the floor tiles on the patio and the gaps to the edges?

That depends on the material in question. Wood stretches more than plastic or stone. Therefore, the information provided by the manufacturer should be observed for the respective distance or joint width.

Can I put floor slabs on concrete in a rented apartment?

There is no general answer to this question. In any case, you should ask the owner, landlord or the apartment or building management whether such a redesign is possible. In some cases it can be stipulated that the application must not be carried out by yourself, but must be carried out by professionals. In other cases, a cost sharing can even be offered if the floor slabs remain on the terrace after you move out.

Category:

Garden design