Roof railings: installation and installation of snow guards

Recommendation points

• Transmitting and non-transmitting
• System selection by roof type and operating conditions
• How to determine the load
• Roof attachment system
• We carry out installation quickly and safely

To make the roof safe, you should prevent the possibility of an avalanche of snow or ice. This is easy enough to solve with the use of modern protective systems and roof fences. We will tell you about the types of snow holders and their correct installation and assembly.

Transmitting and non-transmitting

A snow cap on the roof of the house improves the thermal insulation of the roof, however, too much snow leads to an excess of the permissible load on the rafters, and during thawing, to the simultaneous descent of large masses.

On each roof, snow is retained in completely different ways, respectively, the number of snow holders, their type and location vary greatly from project to project. If the roof has its own ability to trap snow, all that remains is to ensure its even distribution. For these purposes, permeable snow holders are ideal, which leave only a layer of snow of a certain thickness on the roof, and the excess is divided in portions and allow them to slide into the drain.

If the roof does not hold snow, this is eliminated by installing deaf snow barriers. Naturally, with good insulation of the roof, an additional snow layer may not be required; in such cases, snow barriers are not installed at all. But if the thermal protection still needs to be improved, this is within the power of the so-called logs or parapets..

The ability to retain snow is determined not only by the qualities of the coating and the angle of inclination, but also by the throughput of the under-roof insulation. If the roof surface is only a few degrees higher than the air, snow will inevitably adhere even to smooth surfaces..

System selection by roof type and operating conditions

Each of the types of roofing has individual characteristics in terms of reliable and durable fastening of the brackets. Snow holders experience an impressive load during operation, so they are guaranteed to be securely fixed only to the trusses of the truss system. And if with corrugated, but flat coatings like a profiled sheet, this problem is solved by using wider beams, then with metal tiles there are obvious difficulties due to its irregular shape.

Passive snow guards can be oval-shaped tubes or gratings. The difference between them is only in the thickness of the snow cover, at the gratings it is the highest – up to 30-40 centimeters.

Special types of retainers are designed for specific coatings such as shingles. Snow almost never comes off it, but freezes in large layers. On gentle slopes, barriers may not be installed at all, but if the length of the slope is more than 6 meters and the slope is 33 ° and higher, so-called toothed snow holders or snow cutters are necessary. As a rule, they are installed in combination with the main snow barriers only so that the snow cover does not slide to the cornice, but is distributed evenly over the roof.

Point snow holders require special attention. A large number of them are installed on the roof of thin sheet materials. Planks on such a roof cannot be securely fixed, but due to the multiple support points, a rather impressive layer of snow can be retained. To protect against avalanche-like descent in such cases, impermeable barriers are installed, namely logs.

How to determine the load

To begin with, it would be nice to find out the optimal thickness of the snow, so that the thermal insulation improves, and the load on the roof, battens and rafters is not excessive. It is better to carry out these calculations even before designing the roofing system, when the approximate thickness of the insulation is known..

For a thoroughly insulated roof, a snow layer of 7–8 cm is sufficient, a small layer will smooth out the temperature difference and reduce heat loss. Snow on such a roof practically does not melt, remains dry and can be blown away by the wind.

Roofs, in which the space between the rafters is filled with insulation according to the classical scheme, have rather high heat losses. The snow melts on them and is collected in a matter of days. For this reason, the thickness of the cover must be chosen carefully: a layer that is too thick will thicken over time and overload the roof, and too thin for the same reasons will quickly lose its insulating properties..

On slopes with the most common slopes (25–45 °), it will be optimal to maintain a 12–14 cm layer of snow. On steep slopes, it is advisable to reduce the cap to 8-10 cm, and on gentle roofs, you can maintain a layer of 20-25 cm.

As for the specific weight load, it is determined based on the volume of snow per square meter. This value must be multiplied by the density, which varies from 0.25 to 0.4 t / m³ depending on the degree of adhesion. Knowing the thickness of the snow cover, you can easily select the required height of the snow holders and give the rafters and crate the necessary stability, preferably with a 3-4fold margin.

Roof attachment system

There is an opinion that the installation of all kinds of roofing fences and barriers greatly affects the properties of the coating and roofing cake. Therefore, the installation of snow holders is a serious and responsible business that does not tolerate a negligent approach..

First of all, let us understand that the brackets of the snow holders are attached only to the rafter beams, but in no case to the crate, and even more so to the covering itself. It is very important to observe the smallest gap between the body of the bracket and the array of the rafter beam, that is, it is preferable to mount close to the covering in the absence of cavities under it.

The brackets are attached 20–35 cm from the eaves, so the system becomes visible only from a sufficiently large distance. Snow guards can be installed as an assembly, if the conditions and slope of the slope allow it, or in stages, starting with the brackets and ending with the barriers themselves, with their alternate fixation.

Particular attention should be paid to the machining of the holes after drilling and the tightness of the rubber seals to prevent water seeping into the cake. The same places are objects of close observation during periodic inspections of the roof..

For fastening, use long steel pins with a wrench head. The diameter of the fastener should be comparable to the thickness of the rafters, usually for beams with a width of 80 mm, pins of 10–12 mm thick are chosen. For fasteners, a hole with a diameter of 2/3 of the thickness of the thread should be pre-drilled at its narrowest point. This method allows the wood to be neatly compacted at the grip point and makes screwing easier without compromising reliability. The pins twisted in this way are unlikely to break or break from excessive force.

We carry out installation quickly and safely

Roofing work is one of the most dangerous stages of any construction. On slopes more than 11 °, you should only move in the fastened state, for this you can use the brackets just fixed or special handrails.

It is highly recommended to install special walkways before installing snow guards and other roof structures. This will not only save you from injury, but also provide confidence during work, which means that the quality of installation will be high..