Recommendations on the use of a magnesite board (MB)
According to Technical Requirements, MB should be stored in a dry and ventilated room. In the case, if MB is in the open air for some time (for example, at sites), it is recommended to store it under a shelter to protect it from a direct access of moisture. Wet boards should be dried before mounting.
Before the mounting of a magnesite board to a profile system, the MB surface (its front face and inside it, joints) should coated with a coating of deep action for two times.
When mounting a magnesite board, its steam permeability properties should be taken into consideration. That is why, when coating one side of MB with a finishing material, preventing a free absorbance of moisture (ceramic tiles; vaporproof paints, varnishes, wallpaper and others), another side of MB should be coated with water-resistant materials. For this purpose the MB from the inside should be treated with vaporproof materials (hydrophobisator, varnishes, paints and so on) or coated until the formation of a layer on the surface by the method of repeated coating.
Concerning interior work, the MB mounting should be performed during finishing work (in winter with heating on), before the installation of clean floors when all “wet” processes are over, and the distribution of electrical and sanitary engineering systems is performed in the conditions of dry and normal dampness regiments. Moreover, the temperature in the room should not be lower than +10°C. Before mounting, magnesite boards should undergo an adaptation period in a room.
Concerning outdoor work, before the mounting, MB should undergo an adaptation period. The material temperature and environment temperature should not be lower than +5°C.
The cutting of MB is performed with the help of a hand (knife, hacksaw and others) or electric (angle grinder, jigsaw, circ saw) instrument. When you cut a MB with the help of a knife, firstly a cut of the upper layer of fiber glass mesh is done with the help of a metal ruler, then the plate is broken according to the line of the cut, and the fiber glass mesh is cut from the inner face of the sheet. When you cut a MB with an electric instrument, the electric instrument with a dust protector and diamond bit is used.
It is possible to remove a facet from MB ends with the help of a plane or a grinding machine.
It is possible to mount MB both to a metal (wooden) profile system and glue with additional fasteners-“umbrellas”.
Metal profiles for MB mounting should be protected from corrosion.
A pitch of bracketing of profile system is calculated judging from its size, plate thickness and requirements on rigidity of the finished product. The thinner a plate is, the less the pitch of bracketing is. The studs are installed with the pitch not more than 450 mm.
When you use MB as a floor base (according to logs) or as a base for ceramic tiling, tiling with stones, the pitch of bracketing is reduced to 300×300 mm.
MB should be mounted to a profile system with countersunk self-tapping screws (with knurls in the inner side of a head). Self-tapping screws should have anticorrosive coating. Self-tapping screws are fixed at a distance of 10-15 mm from the end of the plate with the pitch of 15-20 cm. If you use traditional self-tapping screws, a spotting in the place of their fixation should be done in advance.
A 2 mm spacing between the boards should be performed at interior work in dry and well-vented rooms, and a 3-4 mm spacing – for damp rooms and outdoor work.
The MB joints are sealed with a magnesia putty С.2.ШМ2 “Ukrmagnesit” with additional reinforcement by a painting tape.
All MB coating works (sealing of joints and places of fixations of screws, surface leveling) are recommended to perform with magnesia putty С.2.ШМ2 “Ukrmagnesit” in the conditions corresponding to the operating ones.
MB is painted with water-dispersible paints that do not prevent a free absorbance and return of moisture.
Author: Kalinichenko Vasyl