Roof waterproofing - construction and installation
The quality, integrity and durability of the roof of the house is determined not only by the characteristics of the roofing. Much depends on compliance with the installation technology and the correct choice of the roofing pie, the layers of which improve the properties of each other, prolonging the life of the roof. When building a cold or warm roof made of corrugated flooring, inexperienced craftsmen often wonder if additional waterproofing is necessary for this roofing. In this article we will talk about which waterproofing materials can be used for the roof of a metal profile building.
Waterproofing features
Waterproofing - an important layer of the roofing pie cold and warm roof of the house of corrugated board, which is mounted on top of the rafter legs using a construction stapler. It is made of waterproofing materials, which do not pass water, protecting wooden structures from getting wet. The waterproofing as a part of a roof from a professional flooring carries out several functions:
- Protection of an internal surface of a professional flooring against corrosion. The weak point of the roof of corrugated board is that the bottom surface of this roofing material is protected only with a paint and varnish coating. Therefore, it can corrode when wet and mechanically damaged.
- Prevent wet insulating material. Waterproofing covers insulation, laid between the roof truss feet. Indeed, with an increase in the moisture content of the thermally insulating material, its efficiency decreases sharply, but does not recover after drying. This function is relevant only for a warm roof of the house, since there is no insulation for installation of a cold roof.
- Prevent nesting of the roof frame. The wooden elements of the truss system, even if they are soaked in an antiseptic, begin to rot on contact with water.
Note! Waterproofing is necessarily necessary for cold and for a warm roof of corrugated board. Due to the difference in temperature inside and outside the house, condensation forms on the lower surface of the coating, therefore the service life of corrugated flooring is significantly reduced.
Requirements for waterproofing materials
Waterproofing under the roof of corrugated is used in difficult conditions, so it must have enhanced strength properties. Signs of high-quality waterproofing material - resistance to moisture, high and low temperatures or their differences, as well as vapor permeability. Skilled craftsmen when choosing choose to take the following factors:
- Density. To withstand the water pressure during leakage, and not to be damaged during installation, waterproofing is needed with a density of 0.04 kg / m2.
- Vapor permeability To cope with the withdrawal of heated air saturated with water vapor from the house, the vapor permeability level should exceed 0.75 kg / m2.
- Water resistant. High-quality waterproofing film withstands water pressure of 10 MPa for 10 minutes.
- Wide temperature range. Waterproofing should withstand temperatures in the range -73 / + 100 degrees.
- Fire Resistance. Since the thermal conductivity of cold or warm corrugated roofing is high, therefore, it is recommended to use non-combustible materials for waterproofing.
- UV resistant. Although the insulation is hidden under the roof covering layer, it must withstand exposure to direct sunlight for 4 months or longer.
Take into account, waterproofing for a cold roof of corrugated board can be any, but for a warm one it is necessary to use only vapor-permeable materials. Using ruberoid or stekloizola as a protection of the structure from moisture, it provokes only more active condensate formation, as well as accelerated wear of the coating.
Material selection
The construction market offers a wide range of insulation materials for roofing, which differ in weight, strength and price. But not every waterproofing is suitable for metal profiles, as it must be vapor-permeable, dense, resilient and moisture-proof. There are 3 categories of waterproofing materials:
- Waterproofing films. So called thin, lightweight films of polyethylene, which have high moisture-proof qualities. They are inexpensive, but have low tensile strength, and therefore may be damaged during installation or operation.
- Diffuse membranes. The membrane is essentially the same waterproofing film. The difference is that it is made of more stable and durable polymers, and also has microscopic holes that provide increased vapor permeability.
- Bituminous rolled materials. Rolled materials based on roofing paperboard or fiberglass impregnated with bitumen are not intended for waterproofing metal roofing, however, they are often used for cold roofs. Roofing material, ruberoid stekloizol and rubemast do not have vapor permeability, but are inexpensive.
Skilled craftsmen pay attention to the fact that it is better to use diffuse and superdiffuse membranes for waterproofing metal coatings. Although they are more expensive, but they have high strength, they let the air better and last up to 100 years.
Design features
The design of the cold and warm roof of the metal profile is characterized by the presence or absence of insulating material in the composition of the roofing pie. The second option is more expensive for developers, it is used if the project involves a heated under-roof room. Different requirements are imposed on waterproofing hot and cold roofs:
- To insulate a cold roof, it is necessary to use durable, durable materials that can cope with high water pressure during leakage. You can even use roofing felt, roofing felt, glass mast or rubemast, despite the fact that they are not vapor permeable.
- Installation of a warm roof requires a vapor-permeable material such as a diffuse or superdiffuse membrane, as it is characterized by increased condensation.
You can not save on waterproofing material, since this little thing, which costs 100-200 rubles per 1 m2, depends on the service life of expensive roofing.
