Water flowing from the roof during rain or snow melt can quickly destroy building structures. Wet walls, broken pavement, sagging soil and cracks in the foundation are the result of the destructive effect of precipitation and frost. Sometimes this leads to a dangerous phenomenon — a decrease in the bearing capacity of the building foundation, leading to irreversible consequences.
To reduce the destructive effect of water on structures, prevent dampness in the basement, and also protect yourself from rain streams pouring from the roof, you need to start installing the downpipe system as soon as possible. This can be done both during the installation of the roof, and after its construction.
The main purpose of gutter systems is to collect rain or melt water from the roof surface and remove it through pipes into a sewer, reservoir or other place. The accumulated liquid can later be used for household needs, for example, for watering or washing a car.
Drains, where precipitation from the slopes flow to the ground arbitrarily, are called unorganized. Unlike them, in organized systems, water is drained by downspouts.
SNiP allow to arrange free flow:
- for pitched roofs of small dimensions;
- in outbuildings;
- with roof overhangs of large width.
Structures can be located inside or outside the building. In multi-storey buildings or buildings with a flat roof, drainage is organized through a pipe laid in non-residential premises, halls, corridors or stairs. To reduce the volume of sound from falling drops, the channel is protected with noise insulation. The drain is connected to the city storm sewer, from where water enters the nearest body of water.
External systems suit in buildings up to 3 floors high. Installation of gutters, catchment funnels and drainpipes is carried out outside the facilities. Structures attached to the outer walls are easy to maintain and repair.
Fluid from external drains flows into concrete grooves or gutters along the perimeter of buildings. They are covered with protective grilles, which can also play a decorative role.
Sanitary codes and regulations prohibit the discharge of rainwater into domestic sewers. If a central storm drain is laid near the site, you can connect to it.
Types of drainage systems
Man has always sought to protect his home from rainwater. At first, these were gutters made from hollowed out tree trunks. With the development of crafts, drains acquired decorative features. Often they were built of ceramics or marble. Later they began to sheathe with sheets of copper, lead, iron, cover with tar, paint.
Now drainage systems are made from corrosion-resistant materials:
- galvanized steel;
- plastic-coated metal;
- cast iron;
- alloys of zinc and titanium.
Do-it-yourself craftsmen make gutters from galvanized sheet, PVC sewer pipes, wooden boards and even plastic bottles.
Metal structures are mechanically strong and durable, they are not afraid of temperature changes, ultraviolet radiation. With low requirements for external attractiveness, galvanized gutters are used. Cast iron funnels and pipes are used to collect water on flat roofs and in multi-storey buildings.
Plastic-coated metal looks decorative. Gutter systems create a single complete composition with the roof, which is an important aspect in the construction of private houses or public buildings.
Pipes are coated with abrasion and corrosion resistant polymers — PVC, polyester, polyurethane, plastisol. Materials are presented in a wide range of colors: from traditional gray, brown or white to unusual bright shades of blue or green. They are combined with walls made of brick, stone, with siding trim. You can choose a design that emphasizes the design of any roof.
Downpipes made of aluminum, copper or zinc-titanium are classified as Premium — these are the most expensive metal structures. They are distinguished by high corrosion resistance, durability and decorative effect. They go well with elite roofs made of slate tiles or copper sheets.
Plastic gutters combine high resistance to moisture, lightness and affordable price. They are made of polyvinyl chloride with additives that increase resistance to UV radiation and mechanical stress. The service life reaches 15 years, the guarantee of individual manufacturers is up to 25 years. They are used in conjunction with roofs made of ondulin or flexible tiles, although other options are possible.
Polymer pipes create less noise than metal pipes. They are less durable than metal ones. In the cold they become brittle. With temperature fluctuations, they can significantly change the linear dimensions, therefore, compensators are used during installation.
Profiles can be round, rectangular or square. There are no strict rules for the selection of sections and sizes.
Elements of drainage systems
The design for the assembly of the drain is completed with:
- gutters — open trays for collecting water from the surface of the slopes, installed obliquely;
- water intake funnels — cone-shaped elements for receiving precipitation from an inclined chute and discharge into a vertical riser;
- gutter connectors — parts for joining trays with sealing gaskets or linear deformation compensators;
- rotary corners — products for connecting trays when rotated by 90 ° -165 ° rectangular or rounded;
- drainpipes — vertical channels transporting liquid from the receiving funnel to the lower outlet;
- tees, swivel elbows — elements assembled from parts of the profile to change the direction or combine two flows;
- horizontal outlets — pipes for draining water from the building, draining it to the ground or into a storm drain;
- clamps — parts for attaching a drainpipe to the wall surface;
- drains — gutters or pipes for draining fluid from the system.
To prevent water from flowing out of open circuits in the opposite direction, plugs are mounted on the ends of the gutters. They additionally give the profile rigidity.
Drainage holes are equipped with lattice panels to trap debris, preventing rapid clogging of the channel. On the paths or the roadway, they ensure the safety of movement.
All components of the drain are selected individually, based on the dimensions and configuration of the building, climatic conditions, the possibility of draining water to a remote location.
Metal and plastic structures are assembled in two ways:
- on seals;
- with glue.
Sealing gaskets made of EPDM rubber or modified rubber ensure sufficient tightness of the connections. When using high-quality materials, the service life reaches decades. Cheap analogues after several cycles of freezing-thawing and heating in the sun lose their elasticity. As a result, leaks occur. Requires dismantling of gutters or downpipes with replacement of gaskets.
Adhesive joints give the nodes additional rigidity, which cannot be unequivocally called an advantage for plastic structures. Thermal deformations can lead to rupture of pipes. In order not to have to dismantle the destroyed sections later, compensatory expanders are additionally installed.
Design and calculation of gutters
When laying any engineering communications, they draw up a project and calculate the elements of the system. The main goal is to choose a design with a pipe cross-section of such a capacity that during heavy rains or melting snow, the drains do not overflow, and the water does not overflow over the edge of the gutters.
It is required to find the total amount of precipitation falling on the drainage area, according to the formula:
Q=Sxq/10000, where Q is the desired value, l/s;
S is the area of the slope, m², q is the intensity of precipitation in the region, l / s per 1 ha (table value).
The next step is the selection of a specific system according to the calculated value Q. Drainage manufacturers provide information in the form of tables, which indicate the throughput qn of the recommended types of structures.
Now you can find the number of risers using the formula:
N= Q/ qn and start designing. It is performed according to the algorithm:
- Determination of the number of gutters. Metal products are produced with a length of 2 m, plastic — 3 or 4 m. Based on the manufacturer’s data, you need to select the number of elements so that as little waste as possible remains during installation.
- Couplings are needed to connect the gutters. They need one less than docking trays.
- The number of brackets is found by the formula: (cornice length — 0.3 m) / 0.6 m +1. In this case, 0.6 m is the fastener installation step, 0.3 is the indent from the edge of the eaves on both sides.
- The number of plugs is equal to the number of open ends.
- When installing a drain with turns, you will need corner profiles. Their number depends on the configuration of the roof.
- The number of funnels corresponds to the number of downpipes.
- The length of the vertical pipe is equal to the height of the wall, excluding knees, which are installed under the eaves and next to the ground.
After calculating the components, you need to choose the right fasteners for gutters and downpipes, the designs of which depend on the installation option. Long holders are fixed before laying the battens, short ones — along the finished roof. In both cases, universal collapsible hooks can be used.
Installation of metal gutters
Metal systems are assembled according to the scheme:
- Install brackets with a longitudinal slope of 2-5 mm per 1 m. Start from the highest and lowest points. The fastening step is 50-60 cm, on both sides of the eaves they recede by a distance of 15 cm. The overhang of the roof should not overlap the tray by more than a third.
- A hole is cut in the gutter for the funnel. The edges are rolled out.
- Trays are installed on brackets, connecting with couplings or latches.
- In the corners and junctions of the slopes, rotary profiles are mounted. Joints with straight gutters are additionally glued with sealant, fixed with rivets.
- They put a funnel on a tray with a hole, snapping the ears. The catchment part must be at the bottom of the line, no further than 150 mm from the blind end.
- They put a plug on the end, pierce it with rivets.
- An elbow and a pipe segment are attached to the funnel branch pipe for connection with another bent element.
- To fix the pipe to the wall, an upper clamp is installed, a measured and cut downpipe is inserted into it and fixed along the length in increments of 1.8 m.
- Mount the ebb at a height of 200-250 mm from the ground or blind area.
The gutters are covered with a net to protect against leaves.
Installation of plastic systems
The installation steps during the installation of plastic elements are similar to the assembly of metal structures. The main difference is the execution of the joints of gutters and funnels.
With temperature differences, the length of polymer parts varies within a few millimeters per linear meter. To compensate for the linear expansion of the drainage system, the funnels are made in the form of a device with graduations on the inner surface corresponding to the possible air temperature during installation. The trays are inserted freely without gluing.
With a slope length of more than 10 m and the absence of a compensating funnel on the line, an expansion element is laid between the gutters. It consists of moving parts that need to be set in accordance with the air temperature. To do this, risks are applied on the inner surface. Glue the trays on both sides of the assembly, keeping the alignment on the marks.
In order to avoid blockages during the operation of the drainage system, in addition to installing catching nets and gratings, regular cleaning is recommended. To do this, in spring and autumn, accumulated garbage is manually collected. If there is a compressor, the pipeline is purged with air. Washing under pressure with water without the use of abrasive agents gives a good effect.
To protect against ice, a set of measures is carried out:
- snow retainers are installed along the cornices on the roof;
- lay heating cables along the drain;
- during heavy snowfalls, the roof is cleared of snow;
- remove ice formations manually.
When working at height, safety precautions must be observed.
Gutter systems will last for many years, subject to proper installation and careful operation.