Dry screed: classic and variations on a theme

Screed - mostly leveling, load-distributing layer, but depending on the species and destination, It can also serve as an additional thermal insulation and sound insulation, as an element of system warm floor. In some situations, both a topcoat, e.g., in a garage or utility room. For a long time the most demanded remained the traditional tie - pouring liquid concrete solution followed by solidification with humidity control. Today, all the more prevalent dry screed in several versions, and users on FORUMHOUSE the basis of classical technologies are coming up with their own and share the results of successful experiments with all concerned.

Classical dry screed

Under dry screed understood multicomponent system and method of creating a floor covering without any wet processes. sex cake consists of several layers, each of which performs specific functions.

waterproofing - often thick polyethylene film, but depending on the type of substrate, it may be specialized membrane and the bitumen and the deposited insulation. The last two types are relevant to the grounds of plate, when it comes to the ceilings of the first floor with unheated basement or directly on the ground.

Compensation (damper) Feed - laying between the wall and the base, which will be in contact with the bed of filler. The commercially available species are made of foamed polyethylene, may have an adhesive strip for easy mounting and "skirt" of oilcloths coming down on rough coating. Replacement of the finished insulation are cut from the substrates and other types izolona foam thickness of 5 - 10 mm. Tape width must be greater than the intended thickness of the screed layer, the excess cut away. When finishing tape to close a plinth mounted to the wall.

Filler - smooth, compacted backfill layer of fine dry composite: expanded clay and dropout, perlite (coarse expanded sand), ash, slag pumice et al. Most often used concrete block different factions.

rough coating - sheets are laid on top of the filling, they become the basis for finishing. This can be a DSP, chipboard, OSB, and the like, but most in demand GVLV GOLS and, in the finished systems the dry screed plates has a mounting groove.

Installation is performed by dry screed standard algorithm:

• Preparation of the substrate - it should be firm and smooth, if necessary, dismantle the old paint down to the floor panels, it may also be required to lower the starting level. On the basis of irregularities should remain as bumps and hollows. The bumps go astray, and the pit sealed with any rapidly solidifying mixture and aligned, remove debris, dust. On the wooden support embedded large gap, the loosened portions change or enhance, also purified from contaminants, ideally - vacuum in both cases.
• Waterproofing - on concrete dim n / e film is not less than 200 m or a special substrate. If necessary, the compound of pieces, their overlapped (10 - 15 cm), the joints were sealed with tape, insulation must go to the wall (10 - 15 cm). If the base wood, according to the same principle of construction was covered with bitumen paper.
• Damper tape - purchase or cut from insulation is glued to the wall (in liquid nails).
• Filling - depending on the equipment available, can withstand level by a laser leveling or water level. According to the level exhibited beacons (convenient to assume Galvanized profiles for gypsum board) in the usual way. In contrast to the usual screed, they are extracted from the dry to the extent of filling stations. Left in the mass, they worsen the parameters of sex. The filler is poured with a margin aligned layer rule ram plaster trowel if necessary.
• Rough coat - it's best to use a special gypsum fiber board with mounting grooves, sheets stacked, glued PVA (tile, and the like), and further fixed with screws (cap Retractable). The second row is laid with ligation (indent 250 mm), it is not recommended to do a joint in a doorway, it will be a weak point of the coating.
• Pruning - remove the protruding portion of the film and the compensating strip.

The average thickness of dry screed layer ranges from 30 to 40 mm, the necessity of increasing the thickness to 60 mm rough coating amplify the second layer plates. Dry coupler provides a sturdy, durable coating, dispersed withstand loads up to 1 tonne per m², and a point load of 360 - 400 kg. The popularity of this method is explained by the characteristics of the resulting base.

• Reduced load - dry variant is much easier when the weight of the screed is crucial, for example, on wooden joists, or when there is doubt as plate overlaps dry screed preferred.
• Reduced thermal conductivity - screed with expanded clay filler 30 mm thick has a thermal conductivity of about 0.12 W / (m * C).
• Soundproofing - at a thickness of 30 mm dry screed dampens noise to 40 dB.

In addition, the dry screed attracted ease of installation, speed and lack of wet and dirty process, disappear mixers, blenders, impossibly high capacity with the solution, and other "charms" of the fill. Limitation to acts of dry backfill slope of the surface, as it is not designed for heavy walls, only light, frame. Although dry screed was "afraid" of moisture, and the Gulf of coating, it is necessary to dismantle it, using a water-resistant gypsum fiber can avoid this danger. In high humidity areas (bathroom, kitchen) is used in a ceramic tile as a final layer. With the technology of preparation of the base and masonry coating is airtight.

dusha82 (Member FORUMHOUSE):

As decided, the floor will be doing on the technology of dry screed - bulk, but with some refinement. I chose this floor for several reasons:

• Lags do not want - will squeak.
• Pour - difficult.
• Self-leveling floor - it's expensive.

Bulk floor - simple, fast and relatively inexpensive. Now about Lapping: very dry screed - leveling and draft floor, but I need (to save), and once to finish cover was, so instead gipsovolokonnyh sheets I decided to take the plywood, later covered with varnish, for the first time pull. I chose two sheets of 8 mm - milled under fold thicker, harder to find. But in the process there was one problem - when poured concrete block and put on trial one fanerku, it turned out that all the "rustling" expanded clay tapped. Fortunately, the hand was a polyethylene foam, the sound has stopped, after I had laid out under the plywood.

"Floating" dry screed

From classic dry screed it differs base - an additional layer of thermal insulation material layer placed underneath the filling: Epps slab or mineral wool (hard). Floating screed called because the filling is insulated from the base layer of insulation and the walls of the damper tape, and due to lack of tight ligaments, is not subject to deformation. This cake maximizes soundproof room, which is especially important in high-rise buildings or private homes for children's rooms and bedrooms. Installation of a floating dry screed does not differ from the installation of classical, just added a heater installation, it is laid end to end, the seams are glued shut. Validating Alexcrab use floating screed precisely to drown out other sounds.

Alexcrab (Member FORUMHOUSE):

There is concrete, the main task of the screed - sound insulation. Will dry screed throughout the apartment (except kitchen), will make a "floating" on the extruded polystyrene foam, 30 mm thick. Also on the floor is the wiring, powerful - in corrugated pipes, low-powered - no, all wiring is laid with a margin over the cross section.

Given that the main purpose of boards - insulation, this tie is indispensable in cold regions or when the plate is laid directly on the ground, or pull out of the basement dampness and cold.

Semi-dry screed

If instead a semi-dry screed expanded clay or other filler is used dry cement-sand mixture with plasticizers, vulcanized fiber and the like additives. Expanded clay or perlite may also be present in admixture or replace part of sand. The main difference from the semi-dry screed is to use in the preparation of liquid filling and no rough layer. Finish is laid directly on the hardened screed in accordance with the selected type of floor technology.

From the usual semi-dry cementitious screed different minimum amount of liquid used - it is enough, to start the hydration process, but batch turns out almost dry and laid on the foundation, and is not It poured. In the process of forming a smooth, streak-free floor that does not require fine-tuning. Among our many members of the forum are using semi-dry screed, like a cross between a dry and normal. It withstands dynamic and vibrational loads that are counter-dry process, but is faster and less labor intensive than pouring the liquid solution.

Turbosol (Member FORUMHOUSE):

I myself am engaged device such ties, in Moscow, we are among the first to offer this technology, although we looked wildly because of the cost at the time. As practice shows, the semi-dry method of quickly replacing the classic method of laying a liquid. Semi-dry screed usually requires no additional leveling Polymer Flooring, rovnitelyami, and they are not small money, though much depends on the master handlers.

Fruitcake (Member FORUMHOUSE):

I think that at the moment it is the best option Ties: no dirt, no need to worry that zalesh anyone, there are no problems with delivery, do not have Problems with the rise of the mixture on high, do not have to worry about where to get the mixer, you can start the next day for further finishing works. Buckle is made on the basis of sand and cement, even if somewhere and will be further leakage of water, she survive without problems, well, the price for me acceptable.

Unlike dry screeds, semi-dry needs moistening during solidification.

Turbosol:

Moisturize, at least once, but it is necessary! To cement completely typed strength, it needs moisture, the reaction occurs only in the presence of liquid (hydration). First humidification is performed five days later - after laying week, before then screed its moisture is present, and it picks up the primary strength to 15 MPa compressive. This, in principle, sufficient for the domestic floor, but it is desirable to increase up to 20 MPa moisture.

Semi-dry screed often make floating due to the high thermal conductivity of the concrete - a layer of insulation can significantly improve the parameters of heat saving space, if a tie - layer insulator. In addition, the floating semi-dry screed less prone to deformation, cracking and shrinkage. And due to the absence of direct contact between the overlapping wall and binders, also obtained an effective sound insulation.

In some situations, the only solution has been and remains the usual screed on the wet method as the maximum corresponding to the conditions of use. And there is nothing to be done with phlegm, dirt and the rest of the attendant inconveniences. However, where not provided for increased loads and dances around the clock, dry screed and its variations can become a worthy alternative.

Dry screed - one suitable base types under infrared film floor, described in the article "Infrared Heated floor - from theory to practice". So that the heat which keeps the floor, does not escape through the windows, read the article about Wooden euro-windows with their hands. In the video, Work with the floor and walls Specialist will demonstrate the device easy ties.

Discuss the article and read other materials devoted to country life you can on the websiteFORUMHOUSE.

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