44. plastering facades in cold weather (winter)

The facades are plastered with heated solutions, without the installation of hot houses, at an outdoor temperature not lower than - 15 ° C. At lower temperatures, it is necessary to warm the surface strongly, which is not always economical.

For the preparation of solutions and storage of materials on the construction site arrange insulated mortar site. However, it is better to prepare solutions in a centralized mortar unit and send them to objects in insulated containers.

If the solution is prepared on site, the water is heated to + 56 ÷ 60 ° C at an outdoor temperature of 0 - minus 10 ° C, to plus 65 ÷ 80 ° C, when the outside air is minus 11 ÷ 20 ° C. At the same time, the temperature of the solution at the exit from the mortar mixer should be, respectively, + 20 ÷ 25 and 35 ÷ 40 ° C, and during application, plus 15 ÷ 20 and 30 ÷ 35 ° C.

For the preparation of the solution, fine sand (grain size up to 1.2-1.5 mm) is used, sifted through a sieve with 2 x 2 mm cells so that the plaster can be rubbed directly on the ground without additional covering. After sifting the sand is heated.

Lime is used freshly or in the form of lime dough. To obtain freshly extinguished lime at the facility, extinguish ground lime-kettle, which is then passed through a frequent sieve and consumed after 48 hours. Compared with ordinary slaked lime (dough or fluff), ground quicklime emits a large amount of heat when extinguished in plaster. Grasping and hardening of solutions occurs faster, and this makes it possible to use such solutions for plastering facades in winter. The disadvantage of ground quicklime can be attributed to the fact that it is quickly extinguished due to the moisture contained in the air, and is carbonized during transportation without proper packaging. Therefore, it is difficult to maintain both during transportation and at the construction site.

For plaster with thick sheets (thrust, cornices) use solutions with antifreeze additives. Solutions with additives are used at an outdoor temperature not lower than -5 ° C.

When plastering smooth surfaces of walls, regardless of the outside air temperature for the soil and covering, a 1: 1: 4 mortar (cement: lime: sand) with sand grains with a size of up to 1.2 mm is used. If the sand is larger than 1.2 mm, then the composition of the soil solution varies 1: 1: 5 (cement: lime: sand).

The consistency of the solutions should be characterized by a draft of a standard cone of 9-11 cm, since at low temperatures and wind the applied liquid solution will freeze faster and the plaster will collapse.

Applying in salt solutions, it is necessary to remember that after drying of the plaster, the appearance of efflorescence is possible. In this case, the plastered places are brushed with a brush or a rag after drying, and then washed with water.

Mortar pumps are installed in a warm room, and hoses going outside are wrapped in felt and sacking.

After each working day, the rastvoronasos and the hoses are inspected, washed first with cold and then with hot water in order to remove the frozen clots of the solution.

In preparing the surfaces, they beat off the stuck plaster and warm the broken-off areas with a blowtorch or a gas torch. After that, the surface is cleaned with steel brushes from soot. The solution is applied on a dry warm surface. Excess moisture is sucked from the solution by the surface and it rather sets and dries.

At one time put layers of plaster 20-25 mm, rubbed the surface after 15-20 minutes after application. With a plaster coating thickness of over 25 mm, the solution is applied in two steps. It is recommended to apply the second layer when the first is already grabbed, but not frozen. If the solution is applied to the frozen layer, then when thawing it will cause the destruction of the upper layer of plaster.

The work should be organized so that during the work shift this or that area is completely plastered. In small areas, the solution is applied manually, with large amounts of work - with pneumatic mortar pumps.

When eaves, belts, platbands and other rods are drawn, the surface is broken up into small sections in order not to leave the applied layer of the finishing solution the next day.

Since the solutions on ground quicklime have a fast setting time, the spray and the ground are applied one after the other without a break.