What Cement Floor Screed To Choose Semi-dry Or Ordinary, What Are The Pros And Cons

2023 Author: Philip Bishop | [email protected]. Last modified: 2023-08-25 07:54

• Features of a semi-dry screed
• Types of semi-dry screed depending on the purpose of the room
• Floor types depending on the required functions
• The technology of creating a semi-dry screed without the use of beacons and without heating
• Foundation preparation
• Preparation of a mixture for a semi-dry screed
• Advantages and disadvantages of a semi-dry screed
• The ratio of water in solution
• Creation of beacon islands
• Video instruction for creating a semi-dry screed
• Electrically heated floor
• Opinion about the quality of a semi-dry floor screed

Every year a person comes up with something new, striving to create universal methods of construction, more solid and durable structures. At the same time, one of the important conditions is high quality and efficiency of work. All this allows you to get a semi-dry screed with your own hands. The resulting surface is durable, resistant to all kinds of loads and perfectly flat.

Today, there are several ways to create a perfectly flat and smooth floor:

• wet screed;
• dry;
• bulk;
• semi-dry.

It is the semi-dry screed that is becoming more and more popular. What are its advantages over conventional concrete pouring? And how to make a semi-dry floor screed with your own hands? There are different ways to level the floor with the beacon.

Firstly, the thickness of a semi-dry screed can reach 5 cm, while it remains strong and durable.

If the screed is much thicker, it is recommended to fill the large cavities with a leveling solution. Or pour it with ordinary concrete with gravel.

Secondly, a semi-dry screed can be easily leveled before the period of complete hardening. When preparing the mixture, well-sifted sand and ordinary high-grade cement are used.

Thirdly, a floor made with a semi-dry screed has the best heat and sound insulation. This is achieved by adding fiber.

Fourthly, when a semi-dry screed is poured, due to the presence of a small amount of water in it, it does not flow beyond the edges of the waterproofing and does not fall into the floor slabs. Thus, it does not cause trouble for the neighbors below the floor.

Fifth, a semi-dry screed, due to the presence of polymer fibers in it, is more resistant to cracking and shrinkage.

Features of a semi-dry screed

With the advent of new building materials, new technologies are being born that make it possible to obtain the same products, but with better characteristics. Liquid cement-sand screed is still the most common, this is most likely due to an incipient habit.

A semi-dry screed with your own hands is made from a solution consisting of the same components, but only the ratio of sand to cement is selected 1: 2. As mentioned earlier, fiberglass is used to increase strength, eliminate cracking and shrinkage, which is usually characteristic of cement mortars.

Fiber is a polymer fiber with a length of 6 to 18 mm and a thickness of 30-35 microns. The novelty allows you to make concrete and plaster products stronger, due to the uniform distribution throughout the volume of the mixture. Such an arrangement of particles, closing with each other, creates a huge resistance to concrete layers, reliably holding them together and creating a monolith.

Types of semi-dry screed depending on the purpose of the room

According to the method of execution, a semi-dry screed can be machine-type and manual. The first type involves the use of special equipment for mixing the mixture, feeding it to the place of screed and mashing. Thanks to the use of technology, the process is significantly accelerated and the resulting surface is of better quality in all respects. The machine method can cover a much larger area of the room in the same time.

Also, depending on the purpose of the room, any screed, including semi-dry, may have a different installation technology. Making a semi-dry screed with your own hands, the video attached to the article will be an excellent guide. Consider some of the most common technologies for creating a screed in the kitchen, which are described in the attached video to the article.

The first way is to level the floor without the need for additional insulation. It can be used not only in private houses, but also in apartments on any floors, while there is no need to worry about repairing neighbors on the floor below.

To create a semi-dry screed with your own hands, the technology can be different depending on the purpose of the room. But at the same time, it can also be performed in different ways:

• using guide beacons;
• using islands or small areas.

The first method can be carried out without using a laser level. Beacons are mounted on a previously prepared surface. These can be T-shaped perforated strips or profiled square pipes. The main idea of this technology is to fill the space between the beacons with a mortar or mixture for screed, and the next day or after at least 12 hours, removing them from the floor and filling the joints with the same mortar, followed by grouting.

We will take a closer look at the method of creating a screed using a laser level.

Floor types depending on the required functions

Depending on the required functions from the room itself, for example, whether heating is required or not, it is possible to divide the floors made with a semi-dry screed into two types:

• without heating;
• heated.

The technology of creating a semi-dry screed without the use of beacons and without heating

If you do not need to mount the floor heating system, then a semi-dry floor screed with your own hands in the apartment is performed exclusively for the final leveling of the surface.

A semi-dry screed does not require further leveling. Thanks to thorough grouting during installation, the surface is perfectly flat and smooth.

Foundation preparation

To get a solid and even concrete floor, it is necessary to prepare the base with the highest quality. To do this, use a vacuum cleaner or a soft broom to thoroughly sweep the subfloor. Large cracks, potholes and pits must first be covered with ordinary mortar. Thus, aligning it with a larger one. Old mortar that is not part of a reinforced concrete slab or monolith must be removed with a chisel and hammer.

The surface, free from dust and debris, must be covered with a bonding primer or other similar material. Modern acrylic primers, in addition to gluing, have excellent antiseptic properties, so a good impregnation ensures always a dry floor.

If the substrate is loose enough, several layers of soil can be applied. It is important to remember that the properties of the screed itself depend on the strength of the subfloor.

A prerequisite for creating a high-quality screed is the installation of a damper tape around the perimeter of the room. It is required to compensate for the expansion of the floor as a result of temperature changes. Pieces of penoizol (foamed polyethylene 4 mm thick), 15 cm wide can be used as it. For convenience, it is better to stick it on some glue.

After processing and drying the floor, you can start creating a semi-dry screed with your own hands, a video of the process of which is available in this article. It is not worth preparing a lot of mixture at once, because the technology under consideration implies the creation of tentative sites, islands, along which we will further level the floor.

Preparation of a mixture for a semi-dry screed

To prepare the solution, you can use a ready-made mixture, which is sold in bags at any hardware store. Or you can make it yourself from sand and cement. The sand must be carefully sifted through a fine sieve. This is necessary so that in the process of work (leveling and mashing) there are no problems with small stones and debris, which is abundant in the river sand.

It is better to use cement of 500 brands and 1 category. To prepare a solution in a ratio of 1: 3, cement is mixed with sand and thoroughly mixed.

An unevenly or incompletely mixed mixture may not be sufficiently plastic, which will significantly worsen the parameters of the screed.

It is recommended to add a little fiber to increase the thermal insulation properties, to avoid cracking and shrinkage. There are several dosages to achieve certain properties. On average, 1 m ^{3 of} screed requires from 0.6 to 0.9 kg of fiber. It is added directly to the mixture or to the water. It is important to mix thoroughly.

If a concrete mixer is used, the mixing time is 15-20% longer than when mixing a conventional mortar. It is important to achieve a uniform distribution of fiber particles throughout the volume of the container.

Advantages and disadvantages of a semi-dry screed

Semi-dry floor screed also has pros and cons. The positive aspects were described earlier in the article. The disadvantages include only a fairly long process of leveling and rubbing a semi-dry screed.

The ratio of water in solution

Be very careful when adding water. It is important not to overdo it, as due to excessive fluidity, the work process will deteriorate significantly, which will lead to a decrease in quality.

In order to check the amount of liquid in the solution, it is enough to crush some of it in a fist. At the same time, moisture should not appear between the fingers, and the lump itself remains unchanged when the palm is opened.

Seven is brought to a uniform consistency state, and they begin to work.

Creation of beacon islands

When creating reference sites, the wet-on-wet technology should be used. That is, before applying the solution, the surface of the subfloor must be moistened, moreover, it is better to do this with an adhesive mixture. Alternatively, tile adhesive diluted to the consistency of kefir or liquid sour cream can be used. Immediately we begin to create an orientation site. To do this, spread the freshly prepared mixture with an approximate amount on a moistened spot. And we level it with a plastic flexible rake or other similar tool.

It is not necessary to buy a rake from a household goods store; the process can be performed with an ordinary trowel, evenly leveling the pile and loosening large glues.

After loosening and even distribution of the solution over the reference site (lighthouse), it must be well thrown. To do this, you can simply walk on it with shoes with a flat tread or use any hand tool. A well pressed surface is rubbed with a float. It is better to use a polyurethane screed, since a semi-dry cement screed creates significant resistance.

The rubbed surface is periodically controlled using a ruler and a laser level previously installed in the center of the room. It is recommended to do this in several places on the site. Small dimples are re-filled with the mixture and rubbed again until a perfect surface is obtained. That's it, the first lighthouse is ready. You can start making the following. It must be done at a distance of 15-20 cm closer than the length of the rule.

The rule is recommended to use a rectangular section and they should work strictly in a perpendicular position.

Slightly cooled and hardened beacons should be located at the corners or edges of the room at the previously indicated distance. This will allow for further work to cover a larger perimeter of the space. While the islands are solidifying, you can prepare the rest of the solution. Its volume can be easily calculated using an online calculator.

Further, the process is as follows:

• The mixture is evenly distributed over the remaining space or small areas. It is compacted, rubbed and leveled with several passes by the rule until the plane is perfectly matched between the beacons.
• It is better to connect the lighthouses with guide strips in parallel to form a kind of runners for working with a screed in the center of the room.

The whole process of working with a semi-dry screed is quite long and requires some diligence, so you should take it with maximum responsibility.

The device of a semi-dry screed requires a humid environment for high-quality crystallization of cement. Therefore, a plastic wrap is used, it is covered with finished screed sections for several days. If you do not use it, then the next day and not earlier than 12 hours, carefully moving along the screed, it must be thoroughly moistened with water for the same reasons.

Video instruction for creating a semi-dry screed

To move on the screed, it is recommended to use special walkers like snowmobiles, but only with a solid flat surface. This will eliminate the likelihood of defects and failures when moving along it. The full curing cycle is at least 1 week at temperatures above 15 ^° C.

Electrically heated floor

The technology of creating an electrically heated floor consists in the use of heat-insulating materials such as expanded polystyrene and expanded polystyrene. On top of them, it is imperative to lay a steel mesh to reinforce the screed, moreover, it should be in its middle. Detailed technology and work process can be viewed in the attached video.

Opinion about the quality of a semi-dry floor screed

Here is a clear example when the technology of manufacturing a dry floor screed is broken.