Installing and aligning beacons – an important preparatory stage of the process of arrangement of the cement-sand screed floor, on the thoroughness of which depends largely on the final result of the entire work. The use of beacons as guides when pouring and distributing the concrete mixture makes it possible to control the thickness of the screed in each point and the level of its surface location relative to the horizon.
Screed beacons for floor screed: types
These days, to level floors with a concrete screed, a special factory building T-shaped profile made of perforated galvanized metal is used. In view of the absence of such, beacons can be made of:
- wooden planks 30-40 mm thick;
- plasterboard profile;
- U-shaped profile, designed for drywall;
- steel pipes of round or square section;
- cement mortar.
Factory building beacons for floor leveling
T-shaped perforated profile is the most convenient to work with. Guides made of it are easily installed on piles of mortar, thanks to the stiffening rib do not sag in the process of leveling the concrete mass, in addition, they do not need to be removed from the half-cured cement mixture, as the galvanized metal from which they are made, does not corrode.
Guide rails made of wooden planks
Making guide rails out of wood is an outdated method. Wooden boards need to be soaked for a long time before installation, so that they do not draw water out of the concrete, which disturbs the structure of the screed. To correctly align the joists, in addition to the self-tapping screws, you have to use wedges and various pads, which complicates the installation process. After the concrete pour has set, such beacons must be removed from the thickness of the screed, and the resulting voids in it are filled with mortar. Because of all these disadvantages, wooden beams for floor leveling are practically not used these days.
Plaster beacons for screed
Plaster profiles are thin and soft, so they are suitable only for the device light three-inch screed in the small area. Such profiles are mounted, as well as building profiles, on piles of mortar.
Guiding profiles for drywall
Such a profile is stronger than a plaster profile, so it can be used in rooms with a larger area. Screed on the U-shaped beacons is made as follows: the metal profile is laid with the base up screwed into the floor and adjusted in height self-tapping screws, and fixed by rims of mortar.
Screed on the beams of pipes – the best way to fill the floors in large rooms. Steel pipes are strong and unbending, so they can easily withstand the weight of massive thick screeds. To create guides, round or profiled pipes are laid on cement slides and, after leveling, cover them with mortar on both sides. After the concrete poured between such screeds dries, the pipes are removed from its thickness, and the grooves remaining from them are sealed with freshly prepared mortar.
Beacons made of cement mortar
To create such beacons, a strong wire is stretched between the opposite walls at the level of the screed and a ridge of mortar is laid along it. The top of the ridge is smoothed with a rule in line with the wire. The resulting horizontal narrow area is used as a beacon after the cement hardens. Guides made of mortar are good in that they have the same structure as the screed, and therefore do not have to be dismantled. Whatever the material used for leveling beacons, they are aligned according to the same principle.
Installation of beacons for floor screed.
Step 1. preparing the base First of all, prepare the base of the screed. Clean the floor slabs of large debris, then vacuum them, patch any holes, sinks, seams and cracks in them, and cover them with waterproofing mastic. Step 2: Determining the zero level and top edge of the screed
- Look around the base of the floor and try to eyeball its most protruding part.
- Place a laser level on this spot, turn it on and look at the walls – a horizontal red line should appear along the floor. If this line is continuous, then you have found the highest point, and the glowing line is the zero level you are looking for. Mark it with a pencil.
- Given that the thickness of the concrete in the highest point of the floor should be 3 cm, defer upwards from the zero level this value and draw a line parallel to it through the mark, it will be the top boundary of the screed, which should be considered when placing beacons.
Step 3 Installing
- Place beacons in parallel rows, perpendicular to the wall with the entrance doors. Mount the outermost screeds at a distance of 25-35 cm from the walls, the gaps between the neighboring screeds must not exceed 1.2 m.
- Chalk out the lines of laying the beacons on the floor, over the ends of the markings screwed into the walls of the self-tapping screws in places where there is a border of the upper level of screed.
- Stretch a thin cord between the opposite self-tapping screws and install the guides, aligning the level of their upper surfaces in accordance with the stretched string.