The calculation of the snow load is carried out as follows:

Using the geometric formula tg a = a / b (the tangent of the angle in a right-angled triangle is equal to the ratio of the opposite leg to the adjacent leg), the height of the roof is divided by half the width of the outer wall of the house. The angle value in degrees is taken from a special table at the end of this section. During the drying process, it must be moistened 2-3 times a day .After 25-28 days, you can start waterproofing the roof with bitumen. To do this, it is necessary to make a small fire near the place of repair work and melt the bitumen. For the preparation of the bitumen mixture, bitumen with the BNK 90/30 marking is used. The bitumen is applied after it has completely melted. The bitumen is applied in an even layer. For distribution, a roller with a hard pile and a metal scraper with a long handle are used.

Roof repair technology with mastic

The process of repairing a roof using bitumen mastic is in many ways similar to the technology of applying liquid rubber. Bituminous mastic, depending on the type, is one- or two-component.One-component compositions, as a rule, are used in conjunction with bitumen-roll and metal roofing coatings. Two-component compositions are used for the installation of flat mastic roofs.The general technology for repairing a roof with mastic is as follows:The surface of the roof, on which there are damages of various nature, must be cleaned of dust, sand and other abrasive particles. To dry the damp roof, a construction hairdryer or heat guns are used, which are placed under a special canopy.
Prepare bituminous mastic Calculate the coefficient µ:
if the angle of inclination of the roof α does not exceed 30 o , it is taken equal to 1;
on steep roofs with a slope of more than 60 o, the snow load is not taken into account at all, that is, µ = 0;
at 30 o ≤ α ≤ 60 o apply the formula µ = 0.033 · (α – 36 o ).
The standard snow load is found on the map of Appendix No. 5 to SNiP2.01.07–85 "Loads and Impacts" or in the table (see below). Each snow region, and there are 8 of them in total, has its own indicator, expressed in kPa or kg / m². For example, in Moscow, which is in the third zone, it is 180 kg / m². according to the instructions on the package. As a rule, an electric drill with a mixer attachment is used for this. If required, the mastic is carefully heated to operating temperatures.
Apply bituminous mastic to the cleaned roof surface. To do this, it must either be carefully poured onto the surface and spread with a scraper and roller, or applied as a paint and varnish coating with a brush and roller.
If the area of work is rather large, then it is possible to apply mastic by airless spraying using a special spray gun. During the repair work, safety precautions must be followed. Mixing and distribution of mastic occurs only with gloves and goggles.

Roofing loads

The loads acting on the roof, that is, the pressure of snow and wind, are calculated in order to determine how many and what kind of rafters will be needed to create a stable frame. We propose to calculate the snow load in practice. Suppose that a house is being built in Kaliningrad with dimensions of 7x10 m and a ridge height of 2.5 m.Then you need to make the following calculations:
Find on the map the normative snow load for Kaliningrad (second zone, 120 kg / m²).
Divide half the width of the wall by the height of the ridge: 2.5 / 3.5 = 0.714.
From the table, find the angle of inclination by its tangent. In our case, it is 36 °.
Determine the coefficient µ: 0.033 · (60–36) = 0.79.
Find the required value of the snow load S = 120 · 0.79 = 94.8 kg / m². Roof repair is a long and labor-intensive process that requires an integrated approach. Overhaul can be avoided by performing a scheduled inspection of the roof structure and fixing any problems found in time. This is especially true for pitched roofs, when for an audit it is enough just to go up to the attic and carefully examine the rafter system for dampness and rot.

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