Laying a semi-dry floor screed: a step-by-step process with photos and videos

For any renovation project, having a perfectly level floor is crucial, and laying a semi-dry floor screed is one of the best ways to accomplish this. This procedure guarantees a level and sturdy base that is prepared for any kind of floor covering, including laminate and tiles.

We’ll walk you through every step of installing a semi-dry screed in this guide, using pictures and videos to help you understand each step as much as possible. Regardless of your level of experience, DIY enthusiasts or novices alike will find the instructions to be clear and simple to follow.

Our services include surface preparation, screed mixing, and screed application. With the correct equipment and a little perseverance, you can accomplish expert-level results at home.

Main types of laying semi-dry screed

There are numerous semi-dry floor screed technologies available:

1. To the base. In this case, the mixture is applied to the prepared base without additional reinforcing elements and substrate.
2. Floating view. First, a polyethylene sheet underlay is laid on the subfloor; the concrete does not adhere to the base and the lower part of the walls.
3. Soundproofed. In addition to the waterproofing layer, a material is laid that reduces noise levels.
4. With insulation. One of the most popular types of screed in cold regions involves laying thermal insulation material. Quite often applied over a “warm floor” system.

Among the types mentioned, the floating screed is the most widely used. In addition to having a long service life and high mechanical strength, it is less expensive than others. The performance characteristics improve and reinforcement is no longer necessary when fiber is used.

A smooth, long-lasting base for a variety of floor coverings can be achieved with ease and economy by laying a semi-dry floor screed. This technique guarantees faster drying times and a more stable surface because it uses less water than conventional screeds. This post will walk you through the entire procedure step-by-step. It includes easy-to-follow directions, professional-looking photos, and videos to make it simple for anyone to follow and get results.

Advantages and disadvantages

When discussing the advantages of this kind of screed, we can point out the following:

1. Relatively low cost.
2. Ease of installation. Semi-dry mixtures just need to be applied to the surface, tamped and leveled.
3. Since a minimal amount of water is added to such compositions, the risk of leakage through the ceiling is excluded.
4. After complete drying, a durable surface is formed, characterized by a long service life.
5. Even in the absence of additional components, such a coating has heat and sound insulation properties.
6. If special equipment is used, then installation occurs very quickly.
7. Semi-dry screed practically does not shrink during drying, so the risk of cracks is minimal.

Note: Unlike with traditional cement-sand mortars, there’s no need to strictly adhere to temperature and humidity conditions when laying such a floor.

The primary drawback of handling these blends is the complexity of preparation. The compositions are thick and crumbly, making it very challenging to mix them thoroughly by hand. Only an electric drill with a mixing attachment or a construction mixer will allow you to prepare the solution. Application presents another challenge. Although it is fairly difficult to lay by hand, a pneumatic pump can make the process go more quickly and easily.

The material needs to be covered with a cloth for protection after it has been laid because it does not respond well to the effects of water. Because this kind of screed is not very dense, it is laid in a fairly thick layer, resulting in a substantial component consumption. It will take too much work to lay a semi-dry screed if you intend to finish a large area. It is preferable to use regular concrete pouring in this situation.

A look at semi-dry floor screed in this video

Necessary tools and materials

To make your own semi-dry floor screed, you’ll need the following materials:

• sand sifted through a fine sieve;
• water;
• cement;
• fiber.

• concrete mixer, buckets and shovels for preparing the mixture;
• pneumatic pump and flexible hoses for application;
• beacons;
• rule, spatula and building level for leveling and control;
• thermal cutting;
• vibrating plate for ramming;
• damper tape.

Optimum thickness and reinforcement

Four centimeters is thought to be the ideal layer. If you increase the size, each square meter of the uneven surface will be compressed by between 90 and 120 kg of screed. Thus, the subfloor is first covered with light expanded clay, and if a thicker layer is needed to level the coating, the solution is applied on the cushion.

Regarding reinforcement, fiber is now assumed when installing a semi-dry floor screed, meaning that steel stacks and reinforcement are essentially no longer utilized. The following are the benefits of this material:

1. Fiber fiber is much easier to add to the mixture than to lay heavy and bulky reinforcing mesh or steel rods.
2. During mixing, propylene threads saturate the solution at all levels. In addition, they are randomly directed, so the stone fragments are securely connected.
3. Propylene fibers perfectly protect the drying surface from cracking.

Some do-it-yourselfers use reinforcing mesh in an antiquated manner; however, in this situation, semi-dry floor screeding becomes a labor-intensive and time-consuming task. A rough layer of two to three centimeters is laid first, followed by a metal mesh whose pieces are wire-fastened, and finally the finishing layer.

Preparatory work

The actual process of installing semi-dry screed is straightforward but requires a lot of work. A well-prepared surface is necessary for this kind of coating; the caliber of subsequent work is contingent upon this step.

Cleaning the surface

To get rid of any last bits of the old screed, the surface must first be thoroughly cleaned with sandpaper or a grinding machine. This will remove the old coating from the base. After that, tidy up any debris and dust. Putty or cement-sand mortar are used to seal any cracks or holes in the coating. A grinder is used to remove protruding parts. Next, you should carefully apply a primer to the entire surface; it is best to do this twice, separated by four hours.

Taking measurements

If you have a laser level, then taking measurements is quite simple. You need to put it on the floor and turn it on, and screw a screw into the floor opposite the wall so that it rises 10 cm above the surface. A rule is installed on its head, at the intersection of the beam and the rule, make a mark on the tool. Then you should do the same operation at the opposite wall. If the mark on the rule does not correspond to the new intersection with the beam, you need to adjust the height by screwing or unscrewing the screw. As a result, 15 screws should be installed; they will be located at different levels, reflecting the curvature of the surface. You need to fill the screed along the self-tapping screw located above the rest, so all the unevenness will be smoothed out.

If you don’t have a laser level at hand, you can use a hydraulic level. Essentially, it is a small diameter flexible tube that is filled with water. It is necessary to measure a certain distance from the floor to the wall to make it more convenient to work, say 1.5 m. Attach one end of the tube to this mark so that the water level corresponds to the point, the other end must be brought to another wall and installed at a height of 1.5 m. If the water level does not reach the mark, then it is necessary to change the height so that the liquid completely fills the tube, make a mark. Thus, you should mark all the walls relative to the first point. The more dots there are, the better. After this, you need to determine the lowest point.

• Let"s say the value of the lowest point is 147 cm. Subtract the layer thickness from this number, for example, 5 cm. We get: 147 – 5 = 142 cm.
• From the arbitrarily marked height earlier, we put aside the obtained distance (142 cm) and draw a horizontal line, this will be the level to which the screed should reach.

Waterproofing and insulation

Waterproofing is accomplished by rolling or coating materials. Film made of polyethylene is the simplest. It needs to be placed on the ground and not fastened to the walls. If one sheet is insufficient to cover the entire area, the strips must be laid with a 15-cm overlap, and the joint must be sealed with tape. Coating materials can be used if the base is in good condition. They are applied, spread, and allowed to dry on the surface using a roller or brush.

The waterproofing layer is covered with insulation. The greatest alternative is thought to be extruded polystyrene. It must be laid firmly and fastened with adhesive tape or specialized locks. Mineral wool is not as widely used. In addition to needing an extra membrane to be installed to guard against moisture from the solution, it offers marginally less thermal insulation.

Next, damper tape is applied to the lower portions of the walls, columns, stairs, and other structural components. The concrete will expand and contract as it dries, which could cause cracks to appear in the walls or in the screed itself. A stationery knife is used to cut the tape after it has dried.

Installing beacons

Beacons are metal or plastic profiles that are used to level the surface.

As a result, you must stand 20 cm back from the wall and draw a straight line every 60 cm using a marker and a building level. Next, make a standard cement-sand mortar and apply small amounts of it along the drawn lines. After that, place one beacon on the mortar. The product must be leveled by pressing or pulling on it. The installation of the subsequent beacons complies with the prior installation.

More skilled artisans use the solution to create beacons on their own. In this instance, it is required to level them and screw in multiple screws along the lines. Next, cover the screws with a piece of tape after applying the solution to the markings. After that, pull the height of the solution portion to the level of the tape using the rule, allow it to harden, and then remove the tape. It is impossible to extract these beacons from the coating.

Making a solution

There is an enormous variety of building mixes available on the market today that only need to be diluted with water to be used. However, if the decision was made to make the solution yourself, it’s crucial to consider the standard ratios: Four parts sand and one part cement. Regarding the fiber, it needs to be added 600 g at a time for every cube of solution. A plasticizer may occasionally be added to the mixture at a ratio of 1 liter per 100 kilograms of cement.

Production steps: fill the concrete mixer with 160 liters of sifted sand, 180 g of fiber-fiber, 500 ml of plasticizer, and 50 kg of cement. Mix everything well, and then add 15 liters of water. After mixing, use a small amount of the mixture and clench it into a fist to assess the solution’s quality. Everything is done correctly if the moisture content is not noticeable.

Video: The procedure for creating a half-dry screed solution

The laying of the screed

The method of installing partially dry screed:

1. Apply the composition around the perimeter of the room, fill in the strips between the beacons.
2. Tamp with the help of a vibro -plate and flatter.
3. Fill the formed depressions with a solution and trigger until the mixture is smoothed out.

You must fill each strip individually and gradually. If you have automated equipment on hand, you can process the entire room at once.

Step	Description
1. Preparation	Clean the surface, remove debris, and apply a primer.
2. Install Damp Proof Membrane	Lay a damp-proof membrane to prevent moisture from penetrating the screed.
3. Set Level Markers	Place level markers around the area to ensure an even screed.
4. Mix Screed	Mix the semi-dry screed using cement, sand, and water in the correct proportions.
5. Lay the Screed	Spread the mixture evenly, ensuring it covers the entire surface.
6. Compact and Level	Compact the screed using a trowel and level it to achieve a smooth finish.
7. Cure the Screed	Allow the screed to cure for a few days, keeping it moist to prevent cracking.

When a semi-dry floor screed is installed properly, it can completely change the foundation of your room by creating a level, sturdy, and long-lasting surface that is ready for your final flooring. You can make sure your project turns out the best by paying close attention to every step of the process, from prepping the subfloor to properly mixing the screed.

Recall that accuracy and patience are essential. Every step should be taken slowly, especially leveling the screed. This meticulous attention to detail will result in a long-lasting, level floor.

Finally, as you work, don’t be afraid to consult the supplied pictures and videos. When dealing with a semi-dry screed for the first time, visual aids can be very beneficial in helping you grasp the subtleties of the process. Even on your own, you can produce results of a professional caliber with the appropriate methodology.

Video on the topic

Semi-dry floor screed, technology and sequence of work

The process of semi-dry floor screed using a pneumatic mortar pump

Ideal beacons for semi-dry floor screed using mechanized technology

Semi-dry floor screed. All the details / How to make a semi-dry floor screed

Semi-dry screed manually. All the details

Floor screed 7 MISTAKES That Everyone Makes. Everyone Should Know.