Which screed is better for underfloor heating: semi-dry or wet? After the advice of the builders, I thought
Mar 07, 2021
Warm concrete floor is a comfortable solution for your home. There are many subtleties when installing this system. For example, such a question: what is the best concrete floor screed to perform in the house, wet or semi-dry? Let's see the pros and cons of each type and calculate the cost per 1 m2.
A wet screed is clear to everyone - it is the pouring (laying) of movable concrete with smoothing the surface:
Beacons are set at the desired height, sand-based concrete is laid out and leveled. The method is simple, if you knead the concrete yourself in a concrete mixer. Sometimes, in order to fill the entire floor area on the floor of the house, imported concrete is ordered. It is dumped into a constructed temporary container and quickly carried in buckets around the premises. This is the way for the brigade.
Concrete for underfloor heating screed should not be too waterlogged. Cracks and sagging may form as it hardens and dries. Ideally, add fiber. The surface of the screed will not be ideal and in case of poor-quality filling, the second stage is necessary - leveling self-leveling floors. For a wet screed, sand concrete or concrete with sand and screenings (small crumbs) are used.
The cost of concrete M200 is 3 thous. rub. (plus shipping). Self-mixed concrete in a ratio of 1 to 3 can be 1.5 times cheaper (depending on the cost of delivery of sand and concrete). A screed for a room of 15 m2 with a screed thickness of 7 cm will cost about 3000 rubles. (if the concrete is mixed and poured by yourself or with an assistant). Of the difficulties - beacons are required.
The second, gaining more and more popular method is a semi-dry screed. Kneading by hand is rare. Companies that do this use special pneumatic blowers, in which the solution is mixed and fed through a hose to the premises. There it is scattered, leveled and smoothed with a trowel:
The process of laying a semi-dry screed is faster (mechanized), a team can make up to 100 m2 of screed per shift. The surface is smoother, immediately suitable for a topcoat. After curing, there are no cracks and defects. Gains strength faster. You can walk on the screed the next day. The screed is lighter than wet. The cost of a semi-dry screed with a layer thickness of 7 cm is 900-1000 rubles / m2, taking into account materials. The service itself - from 250 rubles / m2
Sample prices here: https://express-pol.ru/prajs-list/stoimost-polusuxoj-styazhki
Those. a semi-dry screed for a room of 15 m2 will cost 14,300 rubles. Almost 5 times more expensive compared to the independent work of a wet screed. Comparison of screeds is presented in the table:
You can also see the difference between screeds in this video:
A semi-dry screed for underfloor heating has another drawback - lower heat transfer due to lower density and increased porosity. A screed made using semi-dry technology has a lower heat capacity. Perhaps this is not so critical if the heating of the house is planned not only with warm floors. But you need to consider.
Having weighed everything, it is up to you to decide: fill every room in stages or all at once, calling a team with a pneumosupercharger to fill a semi-dry screed. If the team will do both, the difference is small. And the majority of customers choose a semi-dry screed as a faster and better quality one.
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