How to pour a concrete screed on a wooden floor?

Although it may seem difficult, pouring a concrete screed over a wooden floor can be done successfully with the correct advice. A concrete screed can offer a strong and level base whether you’re looking to level an uneven surface, get ready for new flooring, or just increase the stability of your floor.

It’s important to know the special factors to take into account when working with a wooden base before you begin. Wood is a living, flexible material that has the ability to move and expand. In order to guarantee that the concrete screed is stable and free of cracks over time, this behavior must be addressed.

We’ll walk you through every step of the procedure in this post, from prepping the wooden floor to pouring and smoothing the screed. We’ll go over the required equipment and supplies and offer advice to help you steer clear of typical blunders. After reading this tutorial, you should have a firm grasp on how to achieve a concrete screed of expert quality on your wooden floor.

The feasibility of concrete flooring on a wooden floor

The viability of laying a concrete screed over a wooden floor is still up for debate. Many claim that adding concrete will increase the structure’s weight and, as a result, the foundation’s pressure. Conversely, the brittleness of the wooden foundation will cause the concrete surface to crack and the floor covering to distort. Additionally, there’s a good chance the floor will be uneven. Nonetheless, a number of statistics support coating a wooden floor with concrete:

1. A concrete screed on a wooden floor is poured using a separate technology, taking into account the characteristics of the wood base. The laying is carried out according to the principle of unbound screed, which neutralizes the possibility of deformation.
2. It is recommended to pour cement when aligning and strengthening the base for the arrangement of solid flooring.
3. Concrete is ideal for the installation of warm floors.

You should precisely follow the work’s recommendations to prevent any unfavorable effects from the interaction of wood and concrete. Priming a wooden surface is a crucial step in the preparation process to guarantee adequate moisture resistance. It is advised to use a robust, flaw-free plastic film for waterproofing. Each component part should be placed on top of the overlap. The beacons must be installed in order to create a level surface for pouring. The concrete layer should not be thicker than five centimeters.

It is advised to add plasticizers to the masonry mixture because concrete is a massive and heavy material that can cause the screed on a wooden base to subside or fracture in weak areas of the floor. The solution has enough strength, flexibility, water resistance, and fluidity thanks to these additions, and the screed lasts a long time even under heavy loads.

Execution technology

To strengthen the line separating concrete and wood, a screed is built on a wooden foundation. In order to keep wood and cement from coming into contact and degrading one another’s quality, polyethylene is used to keep the concrete layer from touching the wooden base and the room’s walls. By using this arrangement principle, you can prevent base changes from causing cracks and other damage to concrete. Among the benefits of screed on wooden floors are:

• the mass of the fill must ensure a tight fit of concrete to the floor;
• cement must not touch wood (a layer of film is enough to prevent interaction);
• it is prohibited to pour cement mixture directly onto the wooden flooring;
• it is imperative to arrange a high-quality waterproofing layer.

It is not possible to pour a concrete screed over a wooden surface without first performing calculations and necessary preparations.

Calculations

Prior to beginning the floor arrangement, you ought to perform a computation. The amount of material needed when using a pre-made sand-cement mixture is calculated using the fact that 15 kg/m2 of the mixture creates 1 cm of layer; however, a 10% reserve is required.

If you want to make concrete solutions by hand, you should purchase the materials with a ratio of either 1:6 (cement, a mixture of crushed stone and sand) or 1:2:3 (cement, sand, crushed stone, or gravel). The formula for multiplying the room’s surface area by the necessary screed thickness yields the required amount of material.

Preparing the base

Look closely at the plank covering first. Partially destroyed logs can be turned over, and damaged logs should be replaced. Nails hold the boards back in place. It is advised to use support bars in addition when installing logs with a step greater than 40 cm. Their heads are sunk two to three millimeters into the boards to stop nails from tearing the polyethylene film later.

The old baseboards must be taken apart. It is advised to use thin wooden boards to seal any cracks that develop at the intersection of the wall and the floor. They must be taken out once the pouring is finished. This will guarantee that the wooden base receives natural ventilation and keep it from decaying.

Small cracks in the wooden base can be sealed with parquet putty or sealant on wood dust. Use one part oil paint to four volumes of sawdust to make your own putty.

It is preferable to use polyurethane foam if the cracks are more deeply situated.

Primer and marking

Following the base’s preparatory treatment, dust and debris are removed. The boards are sanded if needed. After cleaning, the surface is primed. This kind of treatment will produce a barrier that stops mold and fungus from growing, bubbles from forming, and moisture from the cement mixture from penetrating the surface.

Regular or laser levels are used for marking. Any height can be the zero mark. Given the thickness of the future screed, it is advised to make multiple marks on each wall at a distance of 35 to 70 cm from the floor. Next, the marking is done from the points on the wall to the floor, going in the opposite direction. A level is used to draw a line in both situations. The thickness of the screed is subtracted from the minimum measurement to find the line of the future alignment.

It is crucial to remember that the screed’s recommended standard thickness is ±5 cm. Here, the pressure exerted by 1 cm of concrete is between 100 and 110 kg/m^2. Beams or metal channels must therefore be used to reinforce the logs.

Waterproofing

Two steps are involved in creating the waterproofing layer:

1. Gluing a damper tape 10-20 mm thick and 2-3 times wider than the screed. Scotch tape is used for fastening.
2. Laying polyethylene with an overlap of 10 cm and an overlap of 20 cm on the walls. If the film is torn or punctured during the work, it should be carefully patched and sealed with tape.

Since the quality of the waterproofing affects the tightness of the entire structure, it is preferable to avoid numerous joints and damage.

Reinforcement

The two most widely used forms of reinforcement are fiber and metal mesh:

1. The technology of installing the reinforcing mesh is carried out using an unconventional method. A layer of concrete is immediately poured without beacons. A break of 1 month is made for hardening. Then the mesh is laid, beacons are installed and the second layer is poured. This technology allows you to avoid unwanted punctures in the waterproofing film.
2. Reinforcement with fiber differs from the above method. The reinforcing material is added directly to the concrete solution at the stage of its preparation. Feature of fiber: its molecules are located in a chaotic order, therefore, when interacting with the molecules of the cement mixture, the material is strengthened in all directions. The use of fiber significantly reduces the overall weight of the concrete coating, therefore, reduces the pressure on the wooden flooring.

Installation of beacons

The beacons are screed mounds made of concrete that are positioned 15 cm apart along the whole perimeter of the future floor, assuming that the 120 cm rule is applied. It should be 25–30 cm from the wall to the indent. Beacons are formed and then covered with a metal profile. The marks that correspond to the leveling layer should be followed when sinking it. Installation needs to happen within the first hour of combining the ingredients. It will be challenging to work with otherwise.

Mixing the solution and pouring

The floor can be poured from a solution prepared from ready-made dry mixes. They are diluted with water to the required consistency, according to the instructions on the package. It is better to use special equipment for mixing. The finished solution must be used within 15 minutes.

It is best to use a 1:3 ratio of M400 cement to river sand for self-preparation. The pre-made solution can be used for one and a half hours. Ordinary washing powder or plasticizers are used to make work more convenient. Water is used to pre-dilute additives. One handful of powder is consumed for every 100 liters of water.

Starting from the corner furthest away from the door, lay the screed. Pour the material into each measured area all at once. The procedure never ends. As soon as the pour is finished, alignment is done. After a day, beacons are taken out, and the holes left behind are leveled with a float and filled with the same solution.

Maintenance of the screed

The screed is moistened with water every day for a week after it is poured the following day. The new floor has a film covering it for the first four days. As a result, moisture will be able to evaporate uniformly across the base.

A practical way to level and strengthen a wooden floor is to pour concrete screed on it; however, in order to ensure stability and avoid damaging the wood, careful preparation is needed. From preparing the wooden floor and selecting the appropriate materials to pouring the screed and making sure it cures properly, this article will walk you through each step and provide a sturdy and level base for your finished flooring.

Tips for work

Suggestions for preventing issues during the work process:

1. It is better to make a heavy layer for the screed on a wooden floor.
2. Waterproofing is a mandatory measure.
3. It is not recommended to pour concrete on fresh wooden boards, as they are still subject to deformation under the significant weight of the screed.
4. The solution should be prepared an hour before pouring.
5. It is not recommended to dry fresh concrete flooring with heating devices. Drying should be natural.
6. It is important to follow the requirements for caring for fresh screed – moistening, insulation with film.
7. Drafts should be avoided in rooms with fresh concrete flooring.
8. You should strictly follow the sequence of pouring concrete.

Although pouring a concrete screed over a wooden floor may seem difficult, it is completely possible with the correct tools and careful planning. The first step is to make sure the wooden floor is strengthened and stable. This avoids problems later on, such as the concrete layer shifting or cracking.

It’s essential to use a waterproof membrane or an appropriate primer to keep moisture off the wooden floor. Both the concrete screed and the wood will last longer after this step. A reinforcement mesh can also be added to the concrete mixture to increase strength and stop cracks in the future.

After everything is ready, it’s crucial to mix and pour the concrete evenly. To get a level surface, make sure you spread it evenly and level it properly. Give the concrete enough time to cure after pouring; this can take a few days to a few weeks, depending on the mix and surroundings.

You can successfully create a stable and long-lasting concrete screed on a wooden floor by following these steps. By using this technique, the floor becomes stronger and provides a stable foundation for different kinds of flooring finishes. You can produce a polished outcome that endures over time with careful planning and execution.

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