The contents
The process of the screed semi-dry type is performed according to the same principles as the standard floor pouring a concrete or cement-sand mortar. Similar purpose of both types of ties – the alignment of the starting bases, in fact, they perform a polished industrial floor or base support. Just use a different composition of mortar, and technological principles work somewhat improved. What else are the differences of the new methods from the standard, and what are the reasons for its popularity in professional circles and among the owners of urban and suburban square meters?
The distinctive advantage of semi-dry casting ↑
Mentioned in the title epithet «dry» the screed has deservedly gained in the preparation of the solution on the new technology uses a significantly smaller volume of water. In the process of kneading the capacity is added to the minimum required for hydration of cement the amount of fluid that is to initiate the process of formation of the stable crystalline connections.
Fig. The consistency of the solution for semi-dry screeds in the first stage
Not receiving excessive moisture, mortar for semi-dry floor screed hardens and transformirovalsya in cement stone. Due to this transformation the fill has gained several significant advantages:
- In the first place – high strength, which is directly proportional to the level of reliability and sustainability for the future construction of the item. Because it is using exactly the amount of moisture how much is enough for installation of the molecular bonds of the components, the process of evaporation in excess of these binding chains of the liquid occurs. Therefore should not form unwanted pores, cavities, voids.
- No shrinkage and accelerated preparation of the screed due to the lack of need for evaporation of excess water.
- In the room increases the humidity indicator, which allows to simultaneously perform other finishing operations. A significant advantage was that erected in front of the screed design of the room in the first place wooden door and window frames are not subject to damage from moisture. Semi-dry floor screed has ruled out these problems.
Drying time dry mortar ↑
Grout non-shrink cover the surface performed after the process of flattening rule. And wait until hardens semi-dry screed floor. How much dry mortar, zameshivaetsya under the new methodology? After 12 hours filled with a mixture of semi-dry the floor can be moved! And after waiting a day in this room for it is quite possible to produce further work on the trim settling space. Proceed to the final laying of the flooring is also permitted a lot sooner than when using the old method of pouring.
But there are nuances. Semi-dry floor screed technology upgraded, but imperfect, therefore, the period of tolerance to different types of works different. It depends on the characteristics used for floor coatings:
- granite or tile resistant to the effects of moisture, you can begin to lay two days later ;
- to lay linoleum allowed in a week;
- to start laying the parquet or laminate floor installation recommended after 28 days, after waiting the time specified in the technological requirements of the standard for all types of cement-sand fills.
Fig. Flooring should be laid after semi-dry screed
Cons of using a semi-dry mortar ↑
With all the advantages of updated technology alignment, semi-dry floor screed has disadvantages. For example, mentioned the benefits of increased strength, slowing down the spreading of the mixture. As a result, the intersection of floor and wall mortar fills the voids in the angles, acquiring a rounded shape.
Semi-dry cement-sand screed is also not recommended for use on large, in excess of 75 m?, areas. The lower limit of the capacity of the filled layer is 30 millimeters, the optimum ratio of thickness – 40-50 mm.
Semi-dry screed floor with their hands ↑
First produced preparatory processes, including diagnostics of sex. By taps with a hammer on the cement surface are determined by peeling the segments are removed by punch and filled with cement mortar. Stray bumps must be filled and re-filled slit.
Then you can move on to the preparation of a mixture for semi-dry floor screed. A video on this topic provided by the network, contains detailed instructions on the proportions of the materials used. Also there are pictures of semi-dry floor screed which demonstrate.
The main stages of the semi-dry screed with their hands in the photo: ↑
- Surface preparation
- Putting the lighthouse
- Batch solution
- Fill the perimeter of the compound for semi-dry screed
- Levelling screed
The mixing of the solution ↑
Purchased cleaned or quarry river sand, cement and additives to improve spreadability. As the capacity for kneading you can use as a specially designed metal containers, and improvised facilities – you can build a trough made of boards and plywood sheet. Also to speed up the process you can use the equipment for semi-dry floor screed, for example, renting a concrete mixer.
The materials included in the composition of the solution for this type of screed should meet the technological requirements. The measure of fineness of sand should not exceed 2.5. Maximum permissible sand content of fine clay compounds – 3%, complete absence of plant residues and peat streaks. Recommended natural moisture level, but this has no specific value, respectively, and the exact proportions of volume of water for mixing dry cement mass is not known in advance. They are defined during the process of mixing on the eyes. Water should be taken from trusted of body of water, not to contain technical or biological waste. It is your regular water.
In the center of the container for mortar for semi-dry screed floor with their hands alternately filled three shovels of sand and one of cement until you reach the required volume. Further, all dry components are mixed, and poured water into which you first need to add fiber. Technology water is poured until the mixture is the consistency called sandy loam – sand should stick together in a lump, when pressed on which of the selection of moisture should be absent.
The use of fibre ↑
Due to instability in the rate of moisture content of sand, the liquid is added «the eye», what could cause the system to exceed its volume in the mix. If a lump of the prepared solution stands out the moisture, it is necessary to add a small amount of cement and sand. In each bucket of water used for mixing the composition, is mixed with polypropylene fiber, about 80 grams per bucket. More accurate proportions of fibrovolokno calculated per cubic meter of solution, specified by the manufacturer in the instructions.
Mechanized ↑
There is also the floor screed semi-dry and mechanized. The mixing pouring and presentation of the material in the planned perimeter is made pneumomechanic. The performance of the works manually from the mechanized method is characterized in that the device semi-dry floor screed technology involves layer-by-layer run-filled first part of the solution and running the rammer, then formed the top layer of screed, rule the sky and ground. To lose its self-levelling properties of the dry mass starts in about 40 minutes-hour, so you need to manage to produce the casting solution prior to the expiration of this time.
Fig. Semi-dry floor screed mechanized
In advance on the perimeter needs to be set to linear beacons in such a way that the rule relied on the rails, the distance from the wall to the rails should be equal to 20-30 centimeters. Mix jumped on the floor, reaching the mark on the beacons, then compacted, the top is filled with the remaining part of the semi-dry mortar, screed compacted, leveled and polished.
After a day in rooms with an area of more than 15 m? you need to cut along the walls of the expansion joints width of 3 mm and a depth equal to one third of the height of the layer. The fill was covered with polyethylene and covered with leaves and left for a week for curing. In hot weather, 5 days screed will need to be wet, so it does not crack and will not warp.
The result is a flat floor plane, in a subsequent correction before laying the flooring, tile, or other coatings, the surface does not need. The shrinkage of the semi-dry floor screed does not, the cracks on it were formed. This is a perfect basis for installation warm floor.
Fig. The semi-dry screed floor finish surface
