Workshop on replacing a wooden floor with a concrete screed

Recommendation points

• Preparation for work
• Dismantling the old wooden floor
• Leveling the ground
• Pillow arrangement
• Insulation laying
• Mortar preparation and screed filling

In this master class, you will learn how to replace a wooden floor in an old house with a concrete insulated screed on the ground. This floor is planned to be used for the installation of a water heated floor. In addition, you will find out what materials you need and their approximate cost..

Preparation for work

To carry out work on the reconstruction of the floor and prepare it for a water-heated floor, we have to do several operations: dismantling the old wooden covering, leveling the soil, filling the pillows, laying insulation, preparing the mortar, pouring the screed.

For work we need the following tools:

1. Buckets (plastic).
2. Construction level.
3. Soviet shovel.
4. The rule.
5. Concrete mixer.
6. Fomka.

Materials that we need based on a room with an area of ​​4×3 m:

Name	Unit rev.	amount	Unit price, rub.	Total cost, rub.
Cement	Kg	250	46	1150
Sand	Kg	3000	0.30	900
Crushed stone	Kg	1000	1	1000
Dropout	Kg	1500	0.60	900
Extrusion	m2	12	263	3156
Styrofoam	m3	0.36	1610	579.60
Total				7685.60

Dismantling the old wooden floor

We disassemble old floors with a crowbar, not forgetting about safety precautions.

Leveling the ground

After the old floor is completely dismantled, it is necessary to remove all the debris from the underground, and the soil should be properly leveled. You can use a rake or shovel.

Pillow arrangement

After the ground is leveled, we begin to equip the pillow. We fill in a layer of granite crushed stone of fraction 20-40 with a layer of 5 cm. We use crushed stone in order to protect the floor from mice. You can replace it with a small break of bricks, or broken slate. Lightly tamp the poured layer of gravel.

Foam sheets are laid along the perimeter of the room to compensate for the thermal expansion of the screed. It will also play the role of a permanent formwork and insulate the ends of the finished slab. The thickness of the foam sheet is from 20 to 50 cm, no thicker needed.

We put a layer of sand up to 10 cm on the crushed stone.The sand must be clean, without debris and foreign inclusions.

Insulation laying

We use extruded polystyrene foam with a thickness of at least 50 mm as insulation. Standard sheet sizes 1.2×0.6 m.

The sheets have a “locking” device in the form of a “step”, this is clearly seen in the photograph. When laying sheets, the locks are connected, and the surface is solid, without gaps.

Since extruded polystyrene foam (extrusion) is completely indifferent to moisture, you can do without waterproofing. We lay the sheets, checking with a level that they lie flat. Add sand in the right places and check again.

Mortar preparation and screed filling

If the room is a walk-through and is actively used (as in our case), fill the screed in two stages. First one half, then the other. To do this, we install the formwork from a long board.

To prepare the solution, we need cement – 1 part, sand – 2 parts and granite screening (small fraction of gray color, resulting from the calibration of crushed stone, i.e. granite dust and very small fragments of crushed stone) – 3 parts.

Advice on how to mix the solution if the components are dry:first we send the screenings to the concrete mixer, then sand, then cement, mix everything thoroughly to dry and only then add water.

Advice on how to knead the solution if the sand or screenings are wet:first, pour water 0.5–0.7 times the volume of a measuring bucket, then add cement, mix thoroughly, then sand, and finally screening. So you will avoid sticking of wet sand to the walls and, as a result, the impermeability of the solution. Then add water to the desired consistency.

The consistency of the finished solution should not flow, but also not be too thick. On a flat surface, when dropped out of a bucket, it will spread into a “cake”, as shown in the photo below.

We wear the mortar and level it with a rule, or a board of a suitable size. The thickness of the screed should be 4–5 cm, it cannot be thinner, it may burst. If desired, you can lay a reinforcing mesh, but you can do without it, since in the future, when arranging a heated water floor, the mesh will be used in the second layer of the screed. This screed is rough, and is only a preparation of the base for a warm floor.

After pouring, let the solution set for at least 48 hours.

We begin to prepare the second part of the room. All works are identical. We remove the formwork, clean the “locks” of the slabs from the sand and lay the insulation. Do not forget to set each sheet by level!

Fill the second part of the room with cement mortar similarly to the first part.

Align the fresh screed in thickness with the already filled.

When the concrete is completely poured, let it settle for at least two days..

After all the work, we should get this floor. You can already walk on it. The screed gains full strength within a month. At this time, it is advisable to moisturize it by watering it twice a day from a watering can. In the future, on this basis, a warm floor will be made based on water heating.