Flat roof slope - leveling and minimum angle

Since the flat roof, used for overlapping office buildings, industrial facilities and residential buildings, has no ramps, there are high demands on the quality of waterproofing. Three to five layers of material are used to avoid leaks, but the flat surface of the roof is not able to drain water as effectively as pitched. Because of this, it creates areas where moisture accumulates, they dry out only in the hottest periods of the year. The rest of the time non-evaporating puddles expose the waterproofing layer to a negative effect, destroying it.

In addition, in places of accumulation of moisture, particles of soil and dust settle down, forming a peculiar substrate. The wind in this favorable environment brings seeds, and they germinate. Destroying the roofing pie. In order to organize the removal of excess moisture and their movement to the drainage system lay the slope of a flat roof. So the name “flat” is just a figure of speech, in fact, its surface is located at a slight angle, not visible to the eye, without using a special geodetic instrument. What should be the bias and how it can be created, we will tell in this article.

Building codes

The minimum slope of a flat roof is regulated by clause 4.3 of SP 17.1333, adopted and approved in 2011. It allows the angle of the roof surface in the range of 1.5-10% or 1-6 degrees. That is, the smallest slope allowed by the regulations, 1.5% or 1 degree, it creates conditions for the movement of water to drain pipes and gutters, prevents stagnation. Steeper corners are rarely used, since over a large area of ​​the roof, rolled waterproofing materials slide off towards the base.

The process of creating a slope is called a flat roof razuklonka. This task is performed in various ways using:

1. Thermally insulating material;
2. Bulk materials;
3. Light concrete mixes with backfill materials;
4. Light concrete blends with polymers.
5. Plastic panels

Important! The slope of the operated flat roof should not exceed 3 degrees, since its increase reduces the safety of use.

Razlonkonka thermally insulating materials

The structure of any flat roof implies the presence of a layer of thermally insulating material. To set the angle of the roof surface, adjust the thickness of the insulation. To prevent slipping and maintain a given angle, it is fixed to the base of the roof with self-tapping screws. If the base of the roof is well cleaned, the insulation to it can be glued or use special plastic supports, grasping the layers of thermal insulator between themselves.

This method of unbundling has advantages, it is good because:

• It is relatively cheap. Since heat insulation is therefore necessary for the formation of a roofing cake, costs are increased only through the purchase of glue or fasteners.
• Accurate enough. Using this method, it is possible to set an angle of 1–4 degrees with great accuracy, which is quite sufficient for effective drainage.
• A light weight. Unlike most other methods, decomposing a flat roof with insulation does not require reinforcement of the base, since the thermal insulating agent, most often mineral wool or polystyrene foam, has a low mass.

Razulukka as a stock material

Creating an angle of inclination of a flat roof with the help of backfill material begins with the installation of a waterproofing material. In this role, stekloizol appears most often, it is a modern analogue of roofing fabric based on glass fabric, due to which it has an increased tensile strength, the service life is more than 20 years. On stekloizol fall asleep clay or perlite so as to withstand the required angle of inclination. After that, the backfill material is covered with a polyethylene film located overlapped with stripes and the remaining layers of the roofing pie are laid according to the project.

However, this method of creating a flat roof slope has disadvantages:

• Large-sized granules (more than 20 mm) do not allow one to precisely observe the given angle to make it smooth.
• Charging material cannot be rigidly fixed, causing it to shift over time. Moreover, this can happen at the stage of the formation of the roofing pie, if you do not fill the clay with cement milk. However, in this case, the time spent on drying increases.
• Backfilling is done almost by eye, so it is impossible to observe the exact angle of inclination.
• Due to the large weight of the backfill material, reinforcement of the concrete base of the roof is required.

Concrete mixes

To set the slope of a flat roof, you can use concrete-based mixtures. This method is not suitable for reconstruction or partial repair, it can only be used for newly created roofs. In order to make a roof razuklonka concrete mixtures require special equipment and highly skilled workers. Apply two types of concrete mixes:

• With the addition of expanded clay and perlite, slag.
• With the addition of polymeric materials.

This method has only two drawbacks: high cost, consisting of the wages of highly skilled workers and the high cost of polymers, and the second is the heavy weight of concrete, which increases the load on the roof base.

Razulonka using panels

The most innovative way to set the angle of the roof is to use special plastic panels. They, like particles of a children's puzzle, are collected and laid on a previously prepared base, and then poured with liquid rubber. Different thickness of the panels provides the most accurate observance of the angle of inclination of the surface. But this way has its own features:

1. The high cost of the panels. Due to the fact that this method is used in Russia not so long ago, domestic producers have not yet entered them into their range. For this reason, it is necessary to use expensive imported consumables.
2. Installation speed Since during the laying of the panels, they do not need to be fastened with screws, to verify the angle with special devices, the leveling is done as soon as possible.
3. The integrated use of panels and liquid rubber allows for simultaneous thermal insulation and waterproofing, which also speeds up the process of building and repairing the roof, with the approach of autumn, this quality becomes decisive in choosing the technology of unraveling.

   

Control of the efficiency of the razuklonka

To check whether the leveling is performed properly and whether water is drained from the roof surface effectively, use one of two methods:

• Instrumental. This requires a special device available in the arsenal of surveyors and builders, inclinometer. Its design consists of several metal rails with a case and a pendulum applied to them. The main rail set perpendicular to the ridge, and the pendulum shows the slope on the scale.

  

• Practical. This method is actively used by builders to make sure that the slope is sufficient for diverting water. To check, take a bucket of water, throw it out and watch it move. If water quickly flows to the drainage system, without forming stagnation, the leveling is done correctly. This method can be used in private construction, because it clearly shows the quality of the work performed.

The razuklonka of a flat roof executed according to construction standards protects the top floors from leakages and prolongs the term of its operation.

Video instruction