The dry screed method has been used for a long time. It became very popular among professionals and amateur builders when there were special complex systems of materials for different types of work.
The company "Knauf" gained wide popularity among builders. Floor elements of this manufacturer are an integral part of the complex for flooring. Their use makes the process of leveling and preparing the surface for coating very technological.
Gypsum board
GVL material (gypsum-fiber sheets) of which the floor element (KNAUF) consists is well-spread in the construction market. Cellulose fibers from waste wood or waste paper are fluffed in a special way and mixed with a gypsum binder. The resulting mass is wetted and pressed into sheets. After drying, grinding and cutting,plates with a thickness of 10-12 mm. So that the gypsum fiber does not stain hands and clothes, it is impregnated with an anti-chalking compound. The main advantages of GVL are environmental friendliness, fire resistance, the ability to absorb excess moisture, heat capacity and sound insulation. If you use water-repellent additives, GVL acquires moisture resistance.
The main disadvantage of GVL is its heaviness, brittleness during transportation and processing. Therefore, it is more convenient to use small-format GVL. "Knauf" makes floor elements from such sheets.
Description of floor elements
Panel for prefabricated base - Knauf "Superpol" floor element - consists of two GVL sheets 10 mm thick, 1200x600 in size. In the factory, they are glued together with a shift of 50 mm in two directions. As a result of the displacement, a fold is formed for assembling the panels into a single deck. Through this fold, the elements are glued together and screwed with self-tapping screws.
The longitudinal edge of the sheets can be straight and inclined - folded, end - straight.
Dry screed technology
The floor on which the prefabricated base is mounted can be concrete (monolithic or prefabricated from slabs) or wooden (with board or sheet flooring). In any case, it is necessary to arrange a hydro- and vapor barrier by laying a PVC film or any roll material of the desired properties. The strips are laid with an overlap of 200-250 mm and an overlap on the wall. This layer will prevent both the consequences of leaks from above and the penetration of moisture from the ceiling.
Enclosing structures -external and internal walls are separated from the future “pie” with a sound-absorbing pad: an edge tape made of foamed polymer material is laid around the perimeter.
A layer of backfill is applied to the film, the minimum thickness is 20 mm. This layer forms a flat surface for laying panels and performs the functions of heat and sound insulation. For backfilling, any material is used, consisting of granules of approximately the same size, with a fraction of 3-5 mm, without inclusions of dust and dirt. Expanded clay sand has the best qualities. On the basis of it, specially prepared fillings for dry screeds are prepared: Compevit, Keraflur, etc.
The backfill is leveled according to the floor level marks determined by a laser or hydraulic level. For this, it is convenient to use a special tool from Knauf: a set of temporary guide beacons and a rule. More often, a profile for installing GVL is used as beacons.
Pro Tip
Experts advise using beacons only for leveling the backfill and not laying GVL (KNAUF) floor elements on them. The layer of bulk material will shrink and compact over time, the panels will begin to rest on the metal, which will lead to noise and reduced thermal insulation of the prefabricated floor structure. Therefore, beacons must be removed.
The fragility of the floor structure without the usual lag is apparent. Carefully leveled backfill and well-placed floor elements produced by Knauf have a very high load-bearing capacity.
They are laid ona leveled surface with a break between rows of at least 250 mm. To assemble the flooring, special glue is applied to the folds of the panels in accordance with the instructions. Then each element of the Knauf floor is connected with self-tapping screws 19 mm long, which are screwed in strictly vertically, sinking the heads of the self-tapping screws.
The last stage of the base device will be puttying the recessed screws and seams between the GVL panels and priming the surface with a hardening compound. After that, the base of the floor is ready for cladding with any finishing coating - both rolled and piece.
The right choice
This floor preparation method has many advantages. These are speed, convenience, independence from temperature conditions, increased sound and heat insulation. Dry screed is a very technological and intuitive construction process. No wonder it is believed that even a person with no experience can make such floors.
To mount prefabricated floors, other board materials are also used: gypsum boards, chipboard, ordinary and moisture-resistant plywood. But only the floor elements produced by Knauf most fully correspond to this technology, significantly enhancing its positive qualities.
