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Making a dry screed covered with particle board or plasterboard makes it possible to retype a soil easily and quickly. In addition to regulating its surface, it improves its thermal insulation.

The implementation of a dry screed consists in spreading a material in the form of granules for straightening a soil that is not flat and improve its thermal insulation. In floor, this solution also provides sound insulation of the floor. In addition to these assets, it should be noted the cleanliness of the site, since there is no mortar to waste with water (hence the name of "dry" screed). Finally, note the speed of the work that allows the installation of a floor covering (floating floor, flexible coating or even tile) without having to wait for any drying.

Vermiculite for more lightness

Among the various solutions of dry screed, that which is based on vermiculite (mica expanded) coated with bitumen is certainly one of the easiest to implement. The floor consists of minimum 19mm thick moisture resistant chipboard (CTB-H) or Oriented Strand Board (OSB) with a minimum thickness of 15mm.
The solution presented here ("Vermaspha" from Efisol) has a long history. The solidity of the soil and its carrying capacity are almost the only constraints imposed for this solution. The support must be naturally rid of badly adhering parts.
In case of very humid environment and risk of capillary rise, a plastic film can be unrolled before the product is put in place. It is not necessary to disburse unless you want to maintain the initial floor level (pay attention to the thickness and inconvenience of the doors).

As for a mortar screed...

Although "dry", this insulating screed is a bit like a mortar screed, by adjusting a layer (3 to 5 cm) erected perfectly level.
The operation is therefore obtained in the same way, by placing cleats on the floor (the height of the layer to be established, less that of the adjustment wedges) and by "pulling" the product with a large rectilinear wooden ruler. or aluminum.
After removing the cleats and wedges, the voids left are simply filled with the product.

Lay cleats and check the levels of the screed

Lay cleats (of the desired screed height) on the floor, as if to make a mortar screed. Stall them and check the levels.

Uniformize the thickness of the screed with a rake

Pour the product on the ground (start in a corner of the room), spread it and uniformly thicken it with a garden rake.

Spread the pellets on the screed with a wooden ruler

Stretch the layer of pellets with a straight wooden ruler. For a better regularity, it is necessary to progress in successive bands of 1 m approximately.

Pack the pellets on the screed with a gardener's roll

When the surface of the screed is leveled, remove the rules and fill in the voids they leave. Pack the product with a gardening roller with a weight of water.

Put shims to prepare the laying of the floating floor

Install shims to prepare the placement of the floating floor. It consists of particle boards (CTB-H) grooved on edge (groove and tongue).

Trace the cutting profile with a compass

Lay the first blank board against the holds. Trace on the cut profile (to work around the wall) using a compass.

Cut the panel with a jigsaw

Cut out the prepared panel using a jigsaw, following the mark. If the site requires several cuts, provide a new blade.

Glue the tongues with wood glue

Then glue the tongues with wood glue spread with a brush. Nest the panels. The job is done, it is possible to put a floating floor, as here.

• Like any bitumen product, Efisol's "Vermaspha" must not be spread at a very low temperature (minimum 5° C). In winter, it can still be used by storing the bags in a heated room for a day. It is best to keep the workpiece at more than 5° C.
• For the floor itself, use tongue-and-groove panels on the four edges, laid with offset joints, and assembled by interlocking and gluing.

Video Instruction: Peikko Floor Joint System