The installation of a drainage system on the roof is an extremely responsible matter, the quality of which depends on the reliability of not only the roof, but also the walls and foundation of the house. It is unacceptable to engage in the construction of a drain "by eye". Only a competent calculation of the drainage system will allow you to create a truly effective and reliable water drainage scheme.
Any drainage system is assembled from a large number of individual elements, these are:
- Pipes;
- Weir funnels;
- Gutters;
- Mounting brackets;
- Couplings;
- Plugs;
- Knees etc.
The principle of operation of the system is as follows: water flowing down from the slopes falls into the gutters located at a slight slope to the funnels.
Further, water through the funnels enters the downpipes, which are used to transport moisture to the drainage system or storage tanks.
The task of the gutter designer is to determine the number and size of gutters, pipes and funnels so that the system matches the roof configuration and effectively copes with the task of rainwater drainage.
It is generally accepted that if the slope area does not exceed 100 square meters, then it is enough to install one drainage from the roof. For large areas, the installation of two pipes is required.
It is also necessary to take into account such a parameter as the length of the gutter. It is believed that weir funnels should be installed for every 10 meters of the gutter. That is, on a roof with sufficiently long slopes, it may be necessary to install an additional pipe.
The procedure for calculating the required number of elements for the drainage system
So, the calculation of drains is carried out in the following order:
- Calculation of the required number of gutters. Manufacturers offer gutters of different lengths. So, metal gutters, as a rule, have a standard length of 2 meters, and plastic ones - 3 and 4 meters. The number of gutters is selected so that the waste during installation is minimal.
Example: If the length of the cornice is 12 meters, then the problem is solved simply - you need to purchase 3 gutters of 4 meters each.And if the length of the slope is 10.5 meters? In this case, it is more profitable to purchase two gutters of 4 meters and one - 3 meters long. As a result, only 0.5 meters of the product will go to waste (4 m + 4 m + 3 m = 11 m).
- Calculation of the required number of couplings for gutters. This calculation is very simple to make: couplings will require one less than the purchased gutters. That is, in our example, where it was necessary to purchase three gutters, only two couplings are required.
- Calculation of the required number of brackets for mounting. To calculate the required number of brackets, you can use a simple formula:
N brackets = (L - 0.3) / 0.6 +1
In our formula, the letter N indicates the desired number of brackets, and the letter L indicates the length of the cornice. 0.6 meters is the recommended bracket spacing.
Example: Calculate the number of brackets needed to fix the gutter on a 12 meter long eaves
( 12 -0,3)/0,6 + 1 = 20,5.
Let's round up, therefore, we need 21 brackets. .
- Counting the number of plugs. A plug is an element that is installed on the ends of the gutter. Their number depends on the system configuration. For example, if the system is closed, then the plugs are not installed
- Counting the number of corners (external and internal). This parameter is determined by the configuration of the roof, the more complex the profile of the roof, the more corner elements may be required.
- Next, you need to calculate the number of drain funnels. Everything is quite simple here, the number of funnels coincides with the number of drainpipes, and the number of the latter is determined by the area of \u200b\u200bthe roof (this was mentioned above).
- Counting the number of elbows of drainpipes.In order to calculate the number of pipes, you need to know the width of the cornice overhang and the height from the eaves to the ground. In addition, you need to consider where the water will drain - just to the ground or to the drainage system.
Advice! The outlet of the downpipe should not be at a height exceeding 20 cm from the ground.
In addition, you should find out what length of pipes the selected manufacturer offers. As a rule, pipes of 3 and 4 meters are on sale.
- Counting the number of clamps that will be used to install downpipes. Two clamps are required for each pipe.
Gutter for flat roof
Buildings with a flat roof cannot be equipped with an external drainage system, since the roof does not have slopes.
In this case, an internal weir is installed. To do this, slopes are arranged on the roof in the direction of the location of the internal funnels.
Drainpipes are installed inside the building with an indent from the walls. IN roof drainage system includes:
- receiving funnels;
- Pipeline;
- Connectors for revision;
- Collector.
Water from such a drainage system is sent to external storm sewer systems.
As a rule, the calculation of the internal drain is carried out according to the same principles as the calculation of the external one. That is, taking into account the catchment area.
The placement of spillway funnels is carried out taking into account the relief of the roof (funnels are placed only in places where the profile breaks), and also take into account such a parameter as the allowable water flow per funnel.
This calculation of drain funnels is made on the basis of tabular data.
| Drain funnel diameter, mm | 80 | 100 | 150 |
| Estimated water consumption per funnel l/s | 5 | 12 | 35 |
Connection of funnels to pipes should be carried out using compensators and elastic seals.
conclusions
As a rule, modern equipment for weir systems is sold fully equipped. When purchasing this equipment, it should be taken into account that manufacturers calculate the defining parameters of the system in different ways.
That is, find a universal formula for calculating roof gutters impossible. This greatly complicates the designer's task, since one has to take into account the peculiarities of the measurements taken by one or another manufacturer.
Therefore, it is better to entrust the development of the project and the conduct of calculations to professionals with experience in this field.
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