Preventing a snow cap from collapsing from the roof of a house is much easier than eliminating the consequences. Installing snow guards on the roof is a work for one to two days, you just need to determine the optimal design and installation method depending on the type of roof. In the article you will find all the necessary information about snow guards and how to install them..
As a matter of fact, snow protectors are installed on most urban buildings with pitched roofs during the construction phase in countries and regions with an increased risk of heavy snowfall. During the construction of a private house, it is important to thoroughly study the situation and determine whether protective equipment is needed to prevent snow from falling from the roof, and, if necessary, select the optimal model of the snow holder. In this material, we will consider the main types of protective devices and how the installation of snow guards on the roof is performed.
Why do we need
One notable and not particularly pleasant feature is associated with the pitched roofs. A snow cap accumulates on an inclined surface in winter. With the arrival of warm weather or due to heating from the roof itself, wet snow can melt in an instant. This is no longer fluffy snow, which wrinkles weightless during a snowfall, but an avalanche weighing several hundredweight that can crush a person, a car or damage a neighboring building..
Cleaning the roof from snow by hand is not the most exciting and time-consuming task. It is easier and more reliable to install snow holders – special devices and structural elements of the roof, capable in one way or another to eliminate the risk of snow melting.
The idea of any snow holder is extremely simple. As soon as snow accumulates on the slope, it begins to slide by gravity to the edge of the roof. Snow holders prevent the descent by fixing the hat in place. Further development of events depends on the type of snow retainers.
They are located along the perimeter of the roof at some distance from its lower edge. The reference point for installation is the plane of the outer wall of the house. Place snow guards directly over the point where the roof rafter rests on the wall. The method of fastening depends on the design of the snow guard and the type of roofing material.
There are several options for how to protect yourself from such a development of events:
- Gradually reduce the mass of the snow cap by dosing portions of snow that will fall from the roof.
- Completely block the path of the snow for an avalanche convergence, it will gradually melt, and due to this, the volume of the snow cap will decrease.
- Prudently clear or not occupy the space under the roof so that snow does not pose a threat when converging.
The third option is rarely possible to implement, if the layout of the site allows you to allocate free space under the slopes of the roof, then snow holders are simply not needed.
A great option is a gradual, controlled snow cap melting, dosed and broken into small portions. For this, snow holders are used:
- teeth (for soft roofs).
The main types of snow holders, capable of gradually passing portions of snow from the roof for a safe descent: tubular, gratings, teeth
Since the obstacle on the way of the snow convergence is not solid, then under pressure the snow is pushed between the tubes or grate and parts of it falls down, without causing significant harm, and partially falling into the drain.
To completely block the descent of snow masses, snow holders are used:
- snow “logs”.
The snow cap formed during the winter can only melt and gradually drain into the drainage system along the drain and nothing else.
For roofs with a slope of more than 60 degrees, snow holders are not installed, a simple logic is taken into account – with such a slope, a large amount of snow simply will not linger on the roof, and the precipitation field will immediately fall off in small portions on its own.
In order not to put additional stress on the roofing material, the snow holders are attached directly to the pitched roof lathing or with long fasteners to the rafters. They are positioned above the point where the rafters rest on the external load-bearing wall of the building..
More often, fasteners for snow holders pierce the roofing material through and through, rubber seals are needed so as not to violate the tightness of the layer. Exceptions are snow protectors for folded roofs and teeth for soft tiles..
It is important to correctly determine the row and load capacity of the snow holders. According to the instructions of SNiP 02.01.07–85 Section 5, the calculated snow load is determined for the region where the building is located. Further, using the already Swedish standard SS 831335, the type, size and row of snow guards are determined. This document is used by most manufacturers of roofing material and ready-made solutions for arranging snow retainers..
It is advisable to choose the version of the snow holder with a safety margin, because the rare heavy snowfalls that occur once every 5-10 years, when the snow falls many times more than usual, are especially dangerous. Separately, the roof structure should be taken into account for possible snow drifts with an increase in the load, as well as the location of the entrance door or external equipment installed on the facade of the building, over which the size and row of snow holders should be increased, if possible..
The principle of operation of the frame and plate snow guard is different, and the installation method is the same. Brackets are installed with a step equal to the step of the lathing or rafters. Frames with a rare lattice or plates are already attached to them. Since the useful area of this type of snow holders is larger than that of others under other equal conditions, then the mounts must also be designed for a large load.
On sale there are plate snow guards made in the form of the letter “L”. They are installed without brackets. They are fastened in two lines on the base, moreover, the upper attachment line, closer to the ridge of the roof, should be fixed with a long fastening element that will go into the rafters 2/3 of the depth.
The basis of the structure is a pipe or angle made of galvanized steel or ferrous metal with a polymer coating. They should be fastened along the entire length of the lower edge of the roof slope in one or two rows. For this, special brackets are used, developed for each type of roof separately. The brackets are distributed so that the fasteners are above the sheathing beams or rafters, moreover, without gaps, to ensure rigidity.
For folded roofing, the brackets are clamped to the seam between adjacent strips of roofing material. It is important that only copper snow guards or brackets with copper fasteners are used for copper roofing.
When the supporting elements are fixed, pipes and corners are pulled or snapped in with mandatory fixation with self-tapping screws with a wide press washer.
They are mainly used with soft tiles. The plates covered with crumbs by themselves already sufficiently restrain the convergence of the snow cap, and the hooks simply increase the impact. Point structures are easier to install without compromising the integrity of the roofing.
The hooks or narrow triangles made of sheet steel have a long fastening that slides under the above row of shingles, and is fixed directly to the battens. The snow holders should be staggered. You can determine the frequency and ranks based on the expected maximum load of the snow cap.
For profile roofing materials, polymer point snow protectors can be used, fixed with adhesives.