Why is roof waterproofing necessary and how to do it?

Protecting a building from atmospheric precipitation is a serious task to be solved at the design stage. The main load from their impact is taken by the roofing. During construction, an obligatory stage of work is roof waterproofing, which protects the insulation and frame beams, as well as extending the life of the roof structure. The operational properties and durability of the roof are determined by the right choice of waterproofing. It’s important to find tpo roofers near you, because roof waterproofing is one of the most important points in roof construction, so professional workers should be selected and their prices should be compared.

What is roof waterproofing?

Roof waterproofing materials are an important component of a multi-layer structure, which includes the following elements:

• external coating that protects against the penetration of precipitation;
• a hydro barrier that protects the insulation from absorbing external moisture;
• heat-insulating layer that ensures the safety of heat;
• vapor barrier layer, which is an obstacle to the path of warm air.

Properly selected and professionally installed hydro-vapor barrier reliably protects the elements of the enclosing structure:

• does not allow sediment seeping through the gaps and mounting holes to penetrate into the space located under the roof;
• prevents the possibility of penetration of condensate formed from temperature fluctuations;
• protects the wooden beams of the roof structure from destruction by mold, which develops as a result of moisture absorption;
• ensures the safety of the insulation, the thermal insulation characteristics of which decrease when wet;
• blocks the way for warm air masses that rise in the under-roof space and condense on the outer layer.

Waterproofing for the roof is necessary, as it performs many serious tasks:

• ensures the durability of the roof structure;
• maintains the performance characteristics of the insulation;
• contributes to the maintenance of favorable humidity;
• protects the timber of the rafters.

Materials used for roof waterproofing

A wide range of waterproofing agents makes it easy to choose the best option for a roof of any design. The main thing is that waterproofing materials for the roof meet the following requirements:

• prevent the penetration of moisture;
• had a long service life.

When deciding on the choice of waterproofing layer, pay attention to the following points:

• environmental cleanliness;
• ease of installation;
• maintainability;
• the complexity of fastening;
• practicality.

Most of these criteria correspond to the following types of waterproofing coatings:

• film polyethylene and polypropylene bases;
• perforated roll protection with anti-condensation properties;
• new generation polymeric membranes with synthetic fibers;
• coating mixtures based on bitumen, polyurethane, polymer modifiers;
• sprayable rubber and synthetic ingredients;
• built-up protection based on polymers and roofing material;
• deeply penetrating polymer and synthetic impregnations.

Waterproofing for pitched roofs

Moisture protection requires a professional approach, adherence to the technology of laying a waterproofing coating that provides long-term protection of the roof structure. In the under-roof space of a pitched roof, a physical phenomenon inevitably occurs, called the “dew point”. It is accompanied by the formation of condensation.

This effect is promoted by:

• elevated temperature in the under-roof space;
• Significant fluctuations in indoor and outdoor temperatures.

Traditional methods of waterproofing a sloping roof recommend observing the sequence of layers, installing the following elements in layers:

• Moisture resistant drywall.
• Reliable vapor barrier.
• Special heater.
• Effective waterproofing.
• Wooden crate.
• Roof covering.

Waterproofing films

Films used for waterproofing purposes make it possible to protect pitched roofs covered with metal tiles or slate. Films are characterized by:

• affordable price;
• low weight;
• practicality;
• ease of installation.

Weaknesses include:

• limited service life;
• reduced strength properties.

As a film material can be used:

• polyethylene;
• polypropylene;
• combined coverage.

Roof membranes

Waterproofing membranes belong to a new generation of waterproofing, which provides free air exchange or, as experts say, allows you to “breathe”.

The peculiarity of membrane hydroprotection is the simultaneous performance of the following functions:

• reliable protection of the under-roof space from moisture access from the atmosphere;
• unhindered passage of warm air masses leaving the room.

Consider the features and properties of certain types of membranes that make it easy to convert a cold room under a roof into a residential attic.

Perforated membranes

Peculiarities:

• the presence of evenly spaced stab holes that contribute to the release of water vapor from the room;
• reduced vapor permeability, allowing the use of material for cold rooms;
• the need for fastening with a gap to ensure bilateral ventilation of the insulated roof;
• installation with the perforation located outside, which makes it difficult for moisture to penetrate under the roof.
• Multilayer membranes

Their properties depend on the number of layers:

• single-layer – the simplest and most inexpensive option, which makes it difficult to evaporate condensate;
• two-layer – layers include polyester and a water-repellent coating, which have increased vapor permeability, elasticity and strength;
• three-layer – super diffuse coating, characterized by practicality and enhanced wind protection.