Laying dry floor screed with your own hands: technology and step-by-step instructions

Even though laying a dry floor screed might seem difficult, you can do it yourself if you have the correct advice. Like traditional wet screeds, this method doesn’t require a long drying time, which makes it popular. It is also efficient. When building a new floor or remodeling an existing one, a dry floor screed offers a level and sturdy foundation for your finished flooring.

Dry floor screed has many benefits, one of which is its speedy completion—often in a single day—making it ideal for do-it-yourselfers. In order to create a level and stable surface, a dry mixture of materials is laid down and then covered with flooring sheets.

From setting up your workspace to installing the last floor covering, this guide will take you step-by-step through the entire process. You won’t need to hire a contractor to accomplish professional results with our easy-to-follow instructions. Now let’s get started and discover how using a dry screed technique can completely change your floor.

Materials for the device

The simplicity of use of dry screed sets it apart from other varieties. This is a result of the materials used and the arrangement technique. They fall into two categories, each of which is associated with a particular dry screed layer:

1. Backfill layer. Bulk materials with a mineral composition are used here. These are substances with a granular composition with minimal sediment, good flowability, low hygroscopicity and high porosity. For example, expanded clay chips or expanded clay screenings, perlite expanded sand, fine-grained slag, quartz or silica sand. The optimal size of the crumb is about 5 mm. The recommended standard thickness of the backfill is 30 mm. The main task of the backfill layer is to level the surface and provide good sound insulation. The backfill usually has poor thermal conductivity and requires mandatory tamping.
2. A solid layer of sheet materials. This part is intermediate between the backfill layer and the finishing coating. For its production, OSB or chipboard sheets (moisture-resistant), gypsum fiber boards, waterproof plywood, special combined materials are used. Knauf offers superfloor (1250×650 mm). If gypsum fiber boards and Knauf superfloor elements are used for laying, then waterproofing is not required. It will be enough to seal the seams with moisture-resistant putty. But in the case of OSB and chipboard, an additional waterproofing layer will be needed to prevent moisture from getting in.

When setting up a dry floor screed, it is important to consider the subtle differences in the nuances of each type of material laying procedure.

Go here to learn more about the materials.

Self-laying dry floor screed is an easy and practical way to build a level, long-lasting floor. Anyone can easily achieve professional results with this technique, which involves using dry materials like sand or lightweight aggregates, topped with special screed boards. You can effectively level your floor, enhance its sound and thermal insulation, and get it ready for any final flooring by following a few easy steps. To ensure a smooth and durable finish, this guide will take you step-by-step through the entire process, from setting up the base to applying the last layer.

Requirements

The layers of the structure must meet specific requirements. Their application ensures the screed will operate for a long time and with high quality. Principal variables:

1. Thickness. Consists of two indicators – for the backfill part and the solid. The thickness of the top layer depends on the type of material – gypsum plasterboard, OSB, chipboard. The minimum thickness of the screed is 60 mm, the maximum is 90-100 mm. The elevation level is calculated for each specific case separately. The optimal backfill height is 30-40 mm. To gain height, it is recommended to lay slabs of extruded polystyrene foam between the grain layers.
2. Weight. The value also directly depends on the materials used. The value must be indicated on the packaging per 1 sq. m floor surface. For example, weight 1 sq. m of screed 4 cm thick on OP backfill is 34 kg, on OP foam – 25 kg.
3. Strength. Optimal strength of dry screed per 1 sq. m floor is 200 kg point load. Compressive strength depends on material. For comparison, on backfill OP is 10 mPa (kg/cm²), on penoplex OP is ~100 mPa (kg/cm²).
4. Density. This parameter depends on the characteristics of the sheet covering, but no significant differences are observed. Typically 2000-2100 kg/m3.

A dry structure’s noise and thermal insulation ratings should also be taken into consideration.

Variations in the primary features of the screed are contingent upon the chosen sheet material.

It is vital to apply the guidelines and specifications found in regulatory documents in order to choose materials with the appropriate parameters:

• SNiP 2.03.13-88;
• SP 71.13330.2017;
• SP 163.1325800.2014;
• SP 20.1333.2017 “SNiP 2”.01.07-85".

The method of laying the dry screed and the type of finishing coating for which it is prepared affect not only the materials used but also the thickness and other indicators.

Preparing the base

There are steps that need to be taken in preparation before installation. This pertains to the base that will have the dry screed installed on it. The first step will be to evaluate the rough foundation, regardless of the kind. This phase will enable you to determine the required tools and materials, estimate the amount of preparatory work, and compute the time and financial costs.

Different terrain calls for a different strategy.

Concrete

In the event that the rough foundation is made of concrete, excavation work is not necessary. If the surface sustains significant damage, the entire layer will need to be disassembled.

The primary steps in preparing the concrete surface to lay dry screed are as follows:

• provide good lighting in the room so you can see all the flaws;
• Clean the existing slab joints, treat them with a primer, and seal them with cement-sand mortar;
• large depressions should also be sealed with mortar;
• widen the cracks and fill them with a special repair compound for concrete;
• clean the base from mortar deposits, splashes and other cement residues using a spatula or hammer;
• After the solutions have dried, clean the base;
• treat with a deep penetration primer;
• lay a waterproofing layer of polyethylene film extending onto the wall = backfill thickness + 20 mm.

There needs to be at least 100 mm of overlap between the film strips.

Wooden

The wooden base’s primary specifications should be:

• durable;
• hard;
• without traces of rot and mold.

It must be thoroughly examined and checked in order to do this. The tree needs to be strengthened by adding more logs or replacing all worn boards if it does not meet the requirements or if it generally has a bad appearance. Steps of preparation are followed:

• seal all large cracks and junctions with walls with epoxy putty or polyurethane foam;
• after the sealant has hardened, cut off any irregularities and then sand them;
• clean the surface of the wooden base from dust and debris;
• treat with an antiseptic;
• apply 2 layers of primer;
• Secure the damper tape around the perimeter of the room with double-sided tape (the width of the tape should be 5-10 cm higher than the screed);
• cover with plastic film with an overlap of 15-20 cm on the wall and stripes with an overlap of 10 cm.

The minimum required film thickness is 100 microns.

Priming

The soil that will be used to create the dry screed needs to meet certain requirements: it needs to be stable, dry, and have deep groundwater.

It is necessary to drain clay and loamy soil!

Phases of preparation:

• mark the “zero” floor level (finish coating level);
• determine the need for excavation by calculating the total thickness of the screed;
• if a excavation is needed, remove the soil to a given depth and level it;
• if excavation is not needed, clear the ground surface of debris and level it;
• be sure to compact the base;
• lay a drainage layer of sand at least 100 mm thick and compact it again;
• lay waterproofing film.

It is now possible to lay dry screed on the soil base.

The backfill layer’s bulk components are hygroscopic. As a result, any kind of uneven foundation must be used to lay the waterproofing layer.

How to do your own styling?

Dry backfill is the first layer, followed by the installation of sheet covering. The technology used for laying is dependent on the material selection. Principles of general installation:

1. Prepare the base. The list of actions depends on its type.
2. Lay a waterproofing layer of polyethylene film with an overlap of strips of at least 20 cm and on the walls up to 15 cm.
3. Attach edge (damper) tape around the perimeter of the room.
4. Align the beacons using a level to evenly distribute the backfill.
5. Start filling material from the highest point. Then level using the rule and compact with a rubber hammer. Minimum backfill level – 4 cm, maximum – 12 cm.
6. Lay a layer of sheet material according to the technology for a specific type.
7. Finally, cut off the excess damper tape with a paint knife to the floor level. Remove any remaining glue or sealant and cover the joints of the sheets with putty.

It’s important to pay attention to the kind of material being used and adhere to the technological guidelines when applying dry screed.

The nuances of working with different types

Let’s examine the key ideas.

Expanded clay

Expanded clay is the material of choice. Sand, gravel, and crushed stone are the three different forms of its grains. Typically, gravel is used for dry screed. Crushed stone made from expanded clay is the recommended material to use if you need to backfill a large area. The material is most frequently used because of its good thermal insulation qualities.

You must select a high-quality filler so that he displays all of his qualities:

• with the same grain size;
• free of sand, dust and other mixtures;
• dry.

The procedure for packing pliable clay:

1. Install damper (edge) tape. It is necessary to ensure that the expanded clay grains do not make creaking sounds when in contact with the wall.
2. Install beacons. First mark the tie line. Then lay two rows of beacons at opposite walls of the room at a distance of 10-20 cm from the walls. You can take aluminum slats from a U-shaped profile. Mark the distance between beacons less than the length of the rule. Install beacons using a level.
3. Fill in expanded clay. It is poured directly from the bags, starting from the far corner, first to the center, and then to the door. When laying expanded clay of different fractions, the bottom layer is formed from the largest grains. Level the surface of the backfill using a rule and compact it with a trowel. During the work process, it is necessary to sprinkle utility lines very carefully.
4. Remove beacons. The remaining recesses should also be filled with expanded clay in small portions. To move on the floor, use sheets of plywood or chipboard.

To stop squeaking, don’t combine sand with expanded clay. The backfill layer is at least 4 centimeters thick.

Vermiculite

This substance is naturally occurring, layered, and a member of the hydromica group. Compared to expanded clay, it is lighter. As a result, it is employed in situations where a minimal load on the floors and gender is required.

Expanded vermiculite is the only material used for dry screed because it does not absorb moisture. The filling procedure is the same as it was before. To prevent it from flying apart, it’s crucial to keep in mind that the material is lightweight. Close the doors and windows and add small amounts of vermiculite to achieve this.

Perlite

Perlite has a volcanic origin. Expanded perlite that has been heated to a high temperature will be used for dry screed.

Used very infrequently because of certain drawbacks. Sand and perlite particles are hygroscopic, meaning they absorb moisture.

Even the smallest breeze can readily disperse small particles. When backfilling, it’s important to keep the area dry and wind-free, pour the material straight from the bag, and wear personal protective equipment.

By type of slabs

This completes the process of applying dry screed. The steps of the procedure in this instance are determined by the kind of sheet material.

Drywall

The special GVL with mounting grooves is the most practical choice. Ordering:

1. Lay the sheets of material in the first row, glue them with glue (PVA, tile, special) and secure with self-tapping screws with an anti-corrosion coating. Lay sheets from the doorway into the room. The screw caps must be recessed.
2. Lay the second row of sheets with dressing (indentation up to 25 cm). It is not recommended to place the joint of sheets in the doorway. In the future, this will become a weak point of the sheet covering. The minimum seam distance from the door is 25 cm.

Following installation, all floor-to-wall joints must have sealant applied, and extra edge tape and plastic film must be cut off.

Plywood

You should use multi-layer plywood for installation that has sheets that are at least 18 mm thick. Plywood comes in two varieties: waterproof (FK, FSF, FB) and non-waterproof (FBA). The FC and FBA types may be used for residential properties.

Before beginning construction, a hydrophobic composition layer needs to be applied to the non-waterproof plywood.

Phases of the project:

1. Place foamed polyethylene under the plywood sheets. This technique will help to avoid the appearance of “rustling” of expanded clay under the plywood.
2. Cut standard plywood sheets into 4 pieces.
3. Attach each part to the bottom layer with screws in the amount of at least 12 pieces.
4. Set the gap between the sheets in layers to 2-3 mm, at the joints with the wall – 1 cm.

Chipboard

It is advised to use moisture-resistant, second-grade chipboard that is labelled "B" and has a thickness of 18 mm. Hydrophobic compounds should be applied to the surface and to the areas that have been cut on non-moisture-resistant varieties. At the joints with the wall, leave a one-centimeter space.

Chipboard must be installed using two different fastening techniques: adhesive and self-tapping screws.

The material needs to be adhered to first. Cover the work surface with the adhesive mixture. Cover it with the chipboard, making sure it is smooth. Keeping in mind the guidelines for bandaging the seams, arrange the panels in rows. Once all of the slabs are laid, fasten them with self-tapping screws spaced 40 centimeters apart.

Difficulties and errors with the device

Even though installation technology is straightforward, the following common errors should be avoided:

1. Incorrect and poor-quality preparation of the base. This includes poor cleaning of the surface from debris, dirt, dust, lack of compaction.
2. Poor choice of material. Before starting work, you need to familiarize yourself with the main characteristics of the materials and compare them with the operating conditions of the floor.
3. Wrong choice of backfill fraction.
4. Lack of skills and necessary tools. In this case, you can make a low-quality screed even from the best components.
5. Incorrect installation of sheet covering, for example, lack of overlap.

In addition, the beacons must be taken out, and self-tapping screws must be used to firmly secure the sheets.

Finish coating

A dry floor screed makes a perfect foundation for applying the finishing coat. There are certain subtleties in the technology that depend on the material selected.

Laminate

Regarded as the most affordable and rapid choice. The technology states that laminate can be installed right away. However, experts suggest allowing the screed backfill to shrink for a few days. The second requirement is that the room’s temperature must be kept at or above +5°C for the duration of the screed sheet and finishing coating installation process. The conventional method for laying laminate or parquet boards is on a dry screed, just like on any other base.

Principal nuances:

• thoroughly remove dust and remove screed sheets;
• install spacer wedges along the perimeter between the wall and the laminate (this also applies to engineering objects);
• start installation from the heating devices;
• Treat the joints of the panels with sealant;
• install skirting boards.

Linoleum

It is not possible to lay linoleum right after screeding. Before

Filling all of the existing seams is required. This is a requirement. Leveling the solution to make it flush with the screed is required after filling in the gaps.

It’s necessary to recess the screw heads.

Sheets are covered with linoleum using the adhesive method. Priming is therefore the second step in the preparation process that will increase the adherence of the sheets to the rolled material. It’s crucial to make sure there are no air bubbles beneath the linoleum when you lay it out. Linoleum sheets are adhered to with double-sided tape.

Tile

It is necessary to reinforce the dry screed with an extra layer of sheet covering before laying tiles or porcelain stoneware. Apply tile adhesive after priming the floor surface before beginning installation. The remaining phases are typical. The kitchen and hallway are the ideal spaces for tiles.

Pros and cons of installation

The technology is thought to be fairly low-cost and straightforward. Consequently, appropriate for do-it-yourself installation. Advantages of the procedure:

• low labor intensity;
• small investment of time;
• absence of dirt and water during operation;
• Possibility of installation at any temperature;
• minimal loads on the supporting base;
• ease of laying communications in the backfill layer;
• additional thermal and sound-absorbing effects.

Minuses:

• high cost of some materials;
• high requirements for laying the waterproofing layer;
• moisture absorption – cannot be installed in a bathtub or shower;
• poor resistance to shock loads;
• reduces the height of the room.

Compared to other types, installing screed yourself is far less expensive. It is also possible to do work from inside the apartment.

Useful video

More details regarding the video’s installation of dry screed:

Step	Instructions
1. Preparation	Clean the floor surface thoroughly, removing any debris, dust, and loose material.
2. Install Edge Insulation	Place edge insulation strips around the perimeter of the room to accommodate expansion.
3. Lay a Moisture Barrier	Spread a plastic sheet or other moisture barrier over the floor to prevent moisture from affecting the screed.
4. Install Beacons	Set up beacons (guides) to ensure an even layer of screed. Adjust them to the desired height.
5. Pour Dry Mix	Distribute the dry screed mix evenly over the floor, starting from the farthest corner and working towards the exit.
6. Level the Screed	Using a straight edge, level the screed by dragging it along the beacons. Ensure the surface is flat and even.
7. Compact the Screed	Lightly compact the screed mix to remove air pockets and ensure a solid layer.
8. Remove Beacons	Carefully remove the beacons and fill the gaps with more screed mix. Level the filled areas.
9. Install Floor Covering	Once the screed is dry, you can install your chosen floor covering, such as tiles, laminate, or carpet.

Doing it yourself can save you money and provide you with the satisfaction of knowing that you accomplished the task of laying a dry floor screed. The procedures we’ve described will help you create a level, smooth floor that will look good for many years.

From prepping the surface to applying the last layer, never forget to take your time. A successful screed requires careful planning, so don’t rush the first steps. In order to build a solid foundation, make sure the surface is clear of debris and clean.

The quality of your work will also be significantly improved by using the appropriate supplies and equipment. A high-quality dry screed mix should be purchased, and before you start, make sure you have all the required equipment. You’ll work more productively and produce better work as a result of this.

Never be afraid to seek assistance when necessary. An additional set of hands can sometimes expedite and simplify the task. It’s also a good idea to have a second set of eyes to proofread your work and identify any errors as soon as possible.

You will be able to create a dry floor screed that satisfies your requirements and standards if you adhere to these instructions and proceed carefully at every stage. I wish you luck on your project and hope you enjoy laying a brand-new, sturdy floor in your room!

Video on the topic

Laying dry screed or super floor from KNAUF "Super Service"

KNAUF-superfloor: installation and stages of work

DIY DRY SCREAD| ALL STAGES OF WORK| DRY FLOOR SCREED!