Roof sealants

To obtain a reliable roofing coating, it is necessary to take time to worry about the quality protection from moisture and other damaging effects of the most vulnerable places (joints and interfaces with auxiliary structures). To ensure such protection, special sealants are traditionally used, with the help of which it is possible to isolate any problem area quickly and without particular trouble. Sealants for roofing, which are a special class of insulating compounds, as a rule, belong to the category of polymeric materials manufactured on the basis of silicon-organic or polysulfide rubbers and bitumen. The unique properties of such sealants (plasticity, moisture and airtightness, as well as resistance to mechanical stress) allow them to be used on roofs made of a wide variety of materials at temperatures from - 55 to + 80 degrees.

Types and applications

Depending on the base used in the preparation of the composition, all sealants are divided into:

• acrylic;
• bituminous;
• polyurethane;
• silicone (rubber).

Consider each of these types of sealing materials in more detail.

The basis of silicone sealant (it is sometimes called rubber) is siloxane rubber, due to which the composition acquires such universal properties as impermeability and plasticity. The combination of these properties with resistance to sudden changes in temperature and sunlight allows its use in the construction of roofs of ceramic tiles. It goes on sale in a specially dosed package (tube) 310 mm long.

Bituminous sealant is made on the basis of modified bitumen with the addition of aluminum pigment as a filler. This fluid material with a pleasant aluminum tint is used most often in the construction of metal roofs. Its advantages include a high level of water resistance, plasticity and durability. In addition, bitumen-based sealants provide excellent adhesion (adhesion) to both dry and wetted surfaces.

With their help, it is possible to seal voids, cracks and seams, often formed in metal coatings, as well as places of articulation with roofing ridge, chimneys and drains. Due to the high toxicity of this material it is allowed to use it only when carrying out outdoor work.

Note! Some modifications of bitumen compositions are resistant not only to sunlight and precipitation, but also to various solvents, oils and other chemically active substances.

Acrylic sealants for roofs are mainly used for sealing cracks, filling joints and joints, as well as for smoothing joints with structures facing the roof. Their use is most effective in those areas where there is a risk of displacement of adjacent structures due to sharp temperature fluctuations, mechanical loads or high humidity.

Modern acrylic compounds are made on the basis of siliconized additives and their characteristics are identical to high-quality silicone, differing from it at a more affordable price. Sealants of this class are distinguished by good adhesion with brick, concrete and other porous bases.

Due to the antifungal additives contained in the sealant, this material prevents the formation of mold and fungus on the roof surface. Made on the basis of acrylic transparent sealant in appearance is not much different from silicone. It provides a perfectly flat and transparent seam when sealing siding coatings and ventilation openings.

Polyurethane sealant изготавливается из полимеризированной при определенных условиях смолы в виде вязкой однородной массы, которая хорошо сцепляется с любой поверхностью. Этот защитный материал очень эффективен при герметизации межпанельных швов на плоских кровлях и может применяться при достаточно низких температурах.

Note! Polyurethane sealants are available in two versions, one of which - sealing - is intended for use on dry surfaces. The second type of this composition has excellent waterproofing properties and is used in conditions of high humidity, as well as for sealing areas that have direct contact with water.

Such a substance is quite easily applied to the treated surface and quickly hardens. For reliable insulation of joints and seams, you will need a very small amount of polyurethane sealant, which is consumed very sparingly when applied. Polyurethane sealant is often used and, if necessary, to protect parts of the roof from UV exposure, as well as from the appearance of microorganisms on its surface.

The use of this material during roofing significantly increases the strength of the entire coating as a whole. In addition, this unique composition perfectly retains its protective properties and is not prone to flaking and destruction for a long time.

Some varieties of polyurethane composition differ in hardness index, which is indicated by special codes according to the classification given below:

1. For sealing joints of roofing coatings, when processing joints with metal, wood and concrete surfaces of auxiliary structures, a roofing sealant with an indicator of PU 15 hardness is used.
2. When treating surfaces of reinforced concrete, glass and metal, insulating compositions with the PU 40 code are used.
3. For processing metal structures, the material with the designation PU 50 is more suitable.

Summarizing the description of the polyurethane sealant, it can be stated that this material is resistant to mechanical stress, moisture and active chemical compounds (acids, gasoline, various oils), and is not subject to corrosion. In addition, he quickly grabs and easily painted with various dyes. Work with this material can be organized even in winter, since it retains its properties at low temperatures. The only thing that is not recommended is to use such a sealant in sunny weather, since its insulating ability is somewhat reduced in bright daylight.

Preparation of surfaces and joints

As noted earlier, the choice of a particular type of sealant to protect problem areas on the roof depends on the type of surface on which it is supposed to be used. In addition, measures to seal the various joints and joints, as well as special expansion joints should be carried out taking into account certain rules that imply the following procedure for conducting operations:

• Works on sealing problem areas begin with their preparation for the application of protective material. To this end, such places are thoroughly cleaned from dust, residual solution and other contaminants. In winter, snow, frost and frost, are removed from the surfaces of seams and abutments with a metal brush;
• in order to obtain an even seam, the areas adjacent to it are recommended to glue with special tape, which should be removed upon completion of work. In order to ensure good adhesion (adhesion) with the sealant, the inner edges of the seam are ground with a special primer before processing;
• when preparing surfaces for processing, the quality of their cleaning is checked by trial application of a small portion of sealant to the problem area. Upon contact with a well-cleaned area, the test compound will not roll under the spatula, which indicates its reliable adhesion to the surface;
• if it is necessary to seal the mouths of the joining points, special sealing (anti-adhesive) gaskets should be used to ensure their reliable thermal insulation. In addition, such gaskets allow you to save on the material consumed for sealing the seam, since they can serve as depth stops when processing deep mouths. As such gaskets are most often used harnesses of polyethylene foam or polyurethane foam.

Application features and prices

You may encounter the features of the use of sealants already at the stage of their preparation, since they may differ in their composition. So, one-component sealants go on sale in ready-made form and therefore do not require preliminary preparation. When using two-component mastic, the ingredients in their composition (base and hardener) must be mixed in a specific sequence and proportion specified in the instructions for use.

Ready-to-use sealants are not allowed to be diluted with solvents that disrupt the structure of the material and significantly increase its hardening time. In addition, each of the types of compositions considered by us has its own, different from the other indicators of readiness time:

1. So, silicone sealant completely hardens in about 30 minutes; at the same time, the rate of its polymerization is determined by the thickness of the seam formed and the temperature of the surrounding air.
2. For the final polymerization of acrylic sealant, a minimum of 21 days is required, although 20 minutes is enough for its full seizure.
3. Polyurethane sealant основательно полимеризуется где-то за 12–14 дней, в то время как его схватывание происходит за 1,5 часа (обратите внимание на то, что при обращении с этим типом герметика необходимо надевать респиратор и перчатки).
4. The ready time of the bituminous sealant applied in thin layers is determined by the number of layers and the ambient temperature.

As for the cost of used sealants - it depends on the specific composition, its performance, as well as the manufacturer. Approximate prices of some types of sealant (per package) are given below:

• polyurethane (Industry PU-25, for example) - up to 450 rubles;
• rubber sealant (Tytan, 310 ml) - from 185 to 240 rubles;
• bitumen sealant - from 70 to 220 rubles;
• silicone - from 160 to 225 rubles.

Video

About Zigger PF Roof Sealant: