Roof passage node

Modern roofing structures are used not only to protect buildings from various climatic influences (precipitation, wind, heat and cold), but they are also a place for channels and shafts of various functional purposes to be brought out. Ventilation channels, chimneys, as well as exhaust hoods, antenna cables and other communications, as a rule, pass through the roof of residential and industrial buildings. For registration of places of their withdrawal to the outside a special structural element is used, the so-called knot of passage through the roof (abbreviated as UE).

Purpose and design features

The main purpose of the passage unit is to constructively design the outflow channels with their simultaneous sealing, excluding ingress of sediments, as well as debris and foreign objects.

The nodes formed in the exit areas of the ventilation shafts through the roof are most often mounted in special reinforced concrete cups or placed directly on its supporting elements (rafters).

For different types of roofs, significantly differing in their design, the corresponding types of gangways should be selected. At the same time, the use of UE of one kind or another, as a rule, is not tied to the class of mounted ventilation, i.e. it can be built into both natural and forced (exhaust) systems.

Depending on the type of roof construction, as well as on the type of ventilation system, the mounting base of the passage unit through the roof (cup) may have various sizes and shapes. It can be rectangular, square, round or oval, depending on the shape of the through hole to be shaped. When mounting, such a glass is simply placed on a metal pipe of a given diameter, made of sheet metal with a thickness of at least 1 mm.

All the resulting structure is then fixed directly on the roof or on a special base, made in the form of reinforced concrete glass. To fix the ventilation passage units on such a glass, which allows the roof structure to be relieved from excessive load, special anchor bolts are used.

Data for design UE

Data for the design of the site and the choice of its varieties are determined based on the following factors:

• slope angle;
• the amount of wind and snow load in the region;
• material and thickness of the attic floor;
• type of roofing material used to close the roof.

If the overlap of the upper floor of the house is made of reinforced concrete slabs - in the latter should be prepared in advance holes of appropriate size and shape, reinforced with glasses of monolithic concrete. The passage through the overlap, made in the form of a lightweight metal frame, is made out in a similar way, with the only difference that the glasses for the pipes are made of metal. The choice of the size and shape of the glass in any case should be made at the stage of preparation of the project structure.

When performing node calculations, the slope of the slope, adjusted for snow and wind loads, should be considered first. In regions with frequent precipitation, it should be taken into account that in winter the weight of snow accumulated on the roof can reach significant values; at the same time it can block both the nodes of the passage through the roof and the channels of its ventilation.

When calculating the loads on the UE, the possibility of exposure to snow masses sliding from the roof during spring thaws should also be taken into account (this always takes into account the quality of the surface of the roofing material).

Types of UE

In construction, the following types of wiring elements are most often used:

• devices with a manually operated valve;
• units with automatic controlled valve;
• nodes without valve.

Nodes equipped with manual valves are distinguished by such remarkable properties as ease of operation and efficiency. In contrast, a special control mechanism is built into the mechanical valve that allows you to open and close it automatically.

Valveless nodes have a constant connection with external space and are most often used in duct-type ducts that require a continuous flow of fresh air.

Note also that the size of the UE for the organization of ventilation fit into a line of values ​​that differ literally by several millimeters, which allows you to use in practice many of their varieties.

Features of UE for chimneys

A special approach to the arrangement of the walk-through units used for bringing the chimney to the roof of the building is explained by the need to comply with fire safety requirements. Indeed, during operation, the outlet nozzle is strongly heated by the furnace gases, which does not exclude the possibility of ignition of flammable materials adjacent to it.

In this regard, the installation of UE in this case, the following requirements:

1. When making a node between the chimney and the roof elements, it is necessary to provide a small gap, the size of which is determined by the applicable building codes.
2. The fire-hazardous area must be laid with a heat-resistant material that excludes the possibility of fire (asbestos, for example).
3. In sections of the passage of the chimney through the roofing, special boxes made of galvanized metal should be used, providing a gap filled with glass wool or other flame retardant material.

A simpler version of the passage through the roof involves the arrangement of a special skirt, which allows to obtain a gap of the required size between the outlet pipe and the hole in the roofing material. The presence of such a gap in addition to protection against fire can compensate for the thermal expansion of the walls of the chimney channel when heated.

Universal Sealer

Nowadays, in addition to typical access points in construction, their simpler modification, which is performed as a universal ring seal, is increasingly used. The difference of this element from other UEs is that it is allowed to be installed on the openings of almost any diameter (using a universal seal, it is possible to seal the passages with a diameter from 3 to 60 cm). The effectiveness of its use is not related to the type of roofing material, that is, such seals provide reliable sealing of all known protective coatings.

Due to its conical shape, these products can be used on pitched roofs of virtually any slope, and their elasticity allows for reliable sealing on wave surfaces of sheeting or slate, for example, stacked with an arbitrary pitch.

Products of this class are made of high-quality silicone, which enables them to work in a wide range of temperatures (from –74 to + 260 ° C).

The advantages of such seals include the fact that silicone retains its properties well under the conditions of exposure to aggressive media and has a long service life compared to conventional rubber.

Features of mounting a universal seal

When choosing a suitable universal sealant, it should be assumed that to ensure the tightness of the passage, the working size of the mounted ring should be slightly less than the diameter of the pipe (about 20%).

For the convenience of mounting the seal, the excess material from the ring is simply cut off. The tight fit of the mounted product to the surface of the roof across the entire profile is ensured by the reliable compression of its flange, which is performed using a special installation tool.

The surface of the pipe is treated with pre-prepared soap solution, which makes it easy to fit the seal.

After reliable sealing of the joint with a special composition, the seal is fixed on the roof surface by means of self-tapping screws of suitable size, screwed around the circle in increments of about 35 mm.

Universal sealant is in high demand both among professional builders and private traders, which is explained by the simplicity of its installation and high quality sealing.

In conclusion, we note that when organizing typical nodes of a ventilation or chimney passage through a soft roof, instead of a rigid screw fastening, special adhesive mixtures and bitumen mastics can be used, combining fastening and insulating properties. The rules of application of these compounds are determined by the manufacturer and assume the compatibility of their various types with each other (provided that, when mixed, they will not break down and release any chemically active substances).

Video

See how the Master Flash is mounted: