Increasingly, for the arrangement of roofs in modern construction, roofing mastic has begun to be used as an independent roofing material. In this article we will tell you what this coating is, what types of mastics exist, and what properties they have.
Mastic coating
Roofing mastic is a viscous homogeneous mass, which is applied to the roof by pouring. Mastic can be one-component or two-component.
After application to the roof, it hardens.Thus, the coating resembles a monolithic material, somewhat similar to rubber.
Mastics are significantly different from roll roofing roofing materials. They create a kind of membrane or film on the roof. Although mastic roofing has the same properties as rolled roofing, seamlessness is the priority.
Mastic coatings have the following properties:
- resistance to aggressive components of the external environment;
- resistance to UV radiation and oxidation;
- a light weight;
- anti-corrosion resistance;
- elasticity;
- high strength.
The surface of the roof must be even, so that when applying the mastic, the composition is distributed evenly. As a rule, this roofing material is used on flat roofs.
Advice. When the slope angle is above 12 degrees and the air temperature is above 25, it is necessary to apply measures to increase the viscosity of the mastic. For this, additives (cement, thickeners, etc.) are introduced into the composition.
Operational properties
Without a doubt, the quality of the roof depends on the skill of the roofing work. But the quality of the roofing material is of great importance. When using mastic, it is sometimes necessary to change its color, viscosity or hardness. For this, special fillers are added to it.
The main advantage of mastic roofing is the absence of seams and joints in the roofing carpet. The elasticity of the mastic allows you to maintain the tightness of the roof when the roof is deformed.
However, the arrangement of a uniform mastic cover is determined by a perfectly flat surface of the base. In other cases, it is simply impossible to achieve the same layer thickness.
Many attribute this phenomenon to the main disadvantage of mastic.Although to correct it, there is a technology for applying a mastic coating in two layers.
At the first stage, a layer of one color scheme is applied. The second layer has a contrasting color, which allows you to visually determine the uneven coverage of the first layer and correct the shortcomings.
Classification of mastics
Roofing mastics are classified as follows:
- by type of binder - bitumen-latex, bitumen-polymer, chlorosulfopolyethylene, polymer, butyl rubber;
- according to the method of application - cold and hot;
- by appointment - gluing, roofing-insulating, waterproofing-asphalt, anti-corrosion;
- according to the method of curing - non-curing, curing;
- by type of solvent - organic solvents containing water, liquid organic substances;
- in composition - one- and two-component.
Characteristics of mastics
Polymer and bitumen-polymer mastic coatings can be used on surfaces of any configuration and type:
- ruberoid;
- steel;
- concrete.
After evaporation of the solvent from their composition, they harden. This creates a seamless waterproofing film. The amount of dry matter in the material affects the film thickness.
Mastics, which do not contain solvents, harden without changing the thickness of the applied layer. A protective layer is not applied to the mastic coating, as it is colored in bulk. This material is weather resistant.
Modern mastics can be used on new or old roofs:
- for gluing waterproofing or rolled roofing materials;
- for the installation of a protective layer on the roof;
- for the arrangement of mastic roofing;
- for a vapor barrier device;
- on roofs made of falgoizol for anti-corrosion protection.
Mastics are characterized by biostability, adhesive ability, water resistance.
One-component mastics
Roofing mastic, which includes a solvent, refers to a one-component roofing material. .
This mastic is available in sealed containers and is ready for use. The shelf life of one-component mastic does not exceed 3 months.
An exception are polyurethane mastics, which harden when interacting with water vapor in the air.
Polyurethane mastic during curing does not change the thickness of the applied coating. It is stored in sealed packaging for one year.
Attention. One-component mastic hardens in air within an hour.
Two-component mastic
Two-component mastic is delivered to the construction site in the form of separately packaged low-active compounds, the shelf life of which is over a year.
The preparation of a mastic coating is carried out by mixing two compositions, which makes it possible to give the coating elasticity or hardness, depending on the operating conditions of the mastic roof.
Requirements for mask
Waterproofing and roofing mastic compositions during operation should:
- do not emit harmful substances into the atmosphere, in excess of the permissible norm;
- have a homogeneous structure, without the inclusion of various particles;
- not impregnated with astringents;
- show resistance to biological components;
- have the ability to firmly glue rolled materials;
- have stable physical and mechanical characteristics;
- be durable within the operating temperature ranges.
Attention. Compliance of mastic with all requirements predetermines hermetic, durable and reliable arrangement of mastic roofing.
The advantage of mastic
The advantages of mastic are determined by the properties of the material that meet the high requirements for roofing:
- ease of use and application;
- yield to the pressure of roofing tools used in the arrangement of mastic roofing;
- adheres well to vertical and horizontal surfaces;
- forms an elastic coating;
- does not crack when cured;
- the ability to work in conditions of high humidity;
- flexibility at low temperatures;
- durability;
- shrinkage and flow resistance.
The presence of many advantageous indicators determines the relevance of the application hot bituminous roofing mastics when arranging a roof with a small slope of the slope.
Rules for applying mastics
When applying mastics, the roof surface must be cleaned of dirt, dust and other elements.
Mastic can be applied with preheating or cold with a spatula or roller. The number of layers of mastic coating depends on the slope of the slope. Basically two-layer coating is applicable.
As a rule, the thickness of the mastic layer is 1 mm. The drying time of such a layer reaches 24 hours. You can apply mastic in several layers, then the drying interval is from 24 hours to seven days.
Approximate material consumption is more than 1.3 kg per sq.m, provided that the mastic is applied on a flat surface.
When applying mastic on the roof in the cold season, it is recommended to preheat the material, this will contribute to better adhesion to the surface. roof mastic heated at a temperature of 50 degrees in a closed metal container.
To give the coating better performance properties, the mastic coating is sprinkled with roofing powder.
To improve the strength of the mastic roof, the coating is reinforced with a woven mesh (fiberglass mesh) or a panel (fiberglass). Both fiberglass and fiberglass are characterized by high strength, so in most cases they are used as reinforcing elements.
Attention. Additional reinforcement of the mastic roof increases its strength, but at the same time reduces the elastic properties of the coating.
Roofing mastic is indispensable when it is necessary to carry out urgent repair work on roofs of any kind: concrete, roll, mastic, asbestos-cement and metal.
Please note that repairs are carried out without removing the old coating, except in cases of clearing caused by strict necessity due to the presence on the roof of a large number of layers of roll materials applied as a result of numerous repairs.
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