In this master class, we will show you how to make a clean screed for several rooms in one horizon. You will learn how to install an electric underfloor heating cable in different cases. We will also provide practical advice on the construction and maintenance of the screed..
Cement screed is an obligatory layer for floor finishing in most known technologies. We will consider in detail the device of the final floor screed of the 2nd floor according to the finished rough screed with a partial electric floor heating device.
To create a screed you will need:
- Power tool – hand mixer with a whisk, heat gun (if t is below +10 ° С).
- Painter’s tools – trowels, spatulas.
- Measuring tool – tape measure, level 600 mm, rule 2500 mm, cord.
- Hand tools – hammer, knife, metal scissors.
- Inventory – buckets.
- Floor plan indicating the locations of the “warm floor” (hereinafter TP).
- Cement-sand mixture (TsPS-150) at the rate of 50 kg of dry mixture per 1 sq. m.
- Plasticizer “GLIMS-Elastic” (or an analogue) at the rate of 0.05 l per 1 kg of cement or 4 kg of CPF.
- Lighthouses 6 mm – 2 linear meters m per 1 sq. m.
- Electrolux Twin Cable ETC 2-17-100 or an analogue at the rate of 6 rm. m per 1 sq. m.
- Film or other covering material.
In our case, the floors of the second floor need to be made at the same level, but the rough screed has already been arranged.
Attention! If the screed was made by another master, be sure to check the “horizon”. Finishing screed thickness – not less than 30 mm.
Before installing a finishing screed on top of the rough one, only dust removal and a primer are required. Beacons from the rough screed should be removed.
Install beacons for finishing screed on the central heating center in rooms where TP is not provided.
Screed beacons are installed from the horizon according to a long rule on a cement mortar, in which no more than 10% of plasticizing impurities are allowed.
Attention! Do not use gypsum and gypsum mixtures to install the finishing screed beacons. Due to the small thickness of the layer, the screed will crack, since gypsum and DSP have different water absorption.
The distance between the beacons should be less than the length of the rule by 400-500 mm.
After the lighthouses have hardened, lay a cement-sand mortar with additives between them and level it with a rule. Withstand the laid screed for at least 24 hours, install a heat gun if necessary.
Remove metal beacons.
Fill the sinuses left after removing the beacons with a solution.
Question.Why remove beacons – they do not interfere with further work?
Answer.At the point of contact of the solution with a foreign body with a smooth surface, there is no adhesion. Such inclusions weaken, stratify the solution. With temperature changes, this effect is amplified several times..
Pass the filled sinuses with a cotton cloth dipped in water. The final appearance of the floor after stripping will be as follows:
Warm floor (TP)
In rooms where TP is provided, lay out the cable (in our case Electrolux Twin Cable ETC 2-17-100), observing the following requirements:
- Distance between cores – 120-150 mm.
- Distance from the wall – 150 mm.
The wire is fixed to the rough tie using special plastic cable clips that usually come with the cable.
According to the TP plan, under the stationary objects – a bath, a shower cabin – heating is not provided. These places should be bypassed with a wire.
Check the correct installation of the temperature sensors and relays – they must be installed in the corrugation and located in the groove of the rough screed.
The specificity of the bathroom is that the distance between its walls is less than 3 meters. This allows 80% of the screed surface to be laid and flattened in one go. We install the beacons on the solution and align them under the horizon.
After the beacons have hardened, lay and level the solution between them using the rule.
Please note that cable fixing rails are used here – they are used in such cases when you do not need to walk on the wires while laying the screed solution.
The area of this room (kitchen) does not allow laying the screed in one strip, so the wire should be fixed so as not to damage it when installing the first strip. To do this, the wire must be covered with the same compound that will make the entire screed..
Places without a wire should be left open – they will be covered with a common screed.
While fixing the wire with a solution, fill the sinuses of the rough screed beacons.
The type of a correctly recorded heating field of an electric TP will be as follows:
Then, focusing on the horizon, set the beacons to a layer thickness of 10–12 mm and lay the mixture. As a result, the screed will have an even standard appearance.
One of the key points is surface cleaning. Even a professionally performed work on the screed device will have this “defect” – local nodules, remnants of mortar from sealing the sinuses (after removing the lighthouses), nodules in the corners. To eliminate them, it is necessary, after setting the solution (5-10 hours), to clean the influxes with the rule to the beacons. As a rule, this is done the next morning after pouring..
If this is not done, the solution will harden, and the influxes will interfere with further work – the finishing screed will lose its meaning. Cleaning a petrified plane is a laborious mechanized process, so it’s better to do it “raw”.
The screed is correct
A few practical tips for combining screeds into one horizon in several rooms.
Tip # 1
Check the horizon carefully. Anyone who makes money by finishing needs to have a laser level. A mistake at the stage of marking the “zero horizon” can be expensive. Check it several times.
Tip number 2
First, make a clean screed in separate rooms, and then connect it in the hallway. Hardened room screeds will serve as beacons.
Council number 3
It is normal for water to come out of the solution in the correct proportions. Solids settle and squeeze out water.
The water layer on the surface should not exceed 1–2 mm. This water will also be used, gradually saturating the hardening solution. There are two “bad omens” that can be seen immediately in case of poor-quality work:
- water flows down in “streams” on the surface of the wet screed – problems with the level of lighthouses;
- brown (reddish) inclusions are visible – this is sand – poorly mixed mortar mass.
Tip # 4
Cover the screed as soon as possible. M-150 grade solution is extremely unstable to abrasion.
Screed cost per 1 sq. m:
Name Packaging Packing price, rub. Consumption for 1 m2 St-th 1 m2, rub. Cement-sand mixture (TsPS-150) Bag 50 kg 150 25 Kg 75 “GLIMS-Elastic” Canister 5 l 500 0.6 l 60 Lighthouses 6 mm 1 PC. 3m 120 2 m 80 Electrolux Twin Cable ETC 2-17-100 Bay 6 m 2500 6 m 2500 Total materials without TP 215 Total materials with TP 2715 Work without TP 1000 Working with TP 1500 Total without TP 1215 Total with TP 4215