What is membrane roofing
Here to replace the classic bituminous coatings came more modern membrane roofing. This article discusses the characteristics, features of different types of membranes, their production and installation work.
Membrane roofing – a material for the arrangement of roofs of buildings and structures of industrial type, mainly for flat and flat surfaces. Provides waterproofing, protection from weather conditions and environmental influences. It is supplied in rolls. It is flexible, highly durable, easy to lay and has a long service life – up to 50 years.
Advantages and disadvantages of membrane roofing
There are only a couple of disadvantages. They are associated with bitumen, the combination with which destroys this type of coating and nullifies the many advantages of its use.
First, the membrane roofing and polymers in its composition, poorly combined with any bituminous materials. There is a low resistance to the bitumen itself and solvents based on it. Remember that the membranes can not be placed on top of this type of roofing. In addition, aggressive solvents and oil mixtures also destroy the membranes.
Secondly, the cost of membrane roofing is higher than that of bitumen roofing. However, the high quality and performance characteristics justify the price.
The listed disadvantages are considered rather peculiarities and nuances. Much more merits of membrane roofing, which we will list below.
Advantages of membranes
The advantages of membrane roofing materials depend on their types. However, they are also presented as a general list.
- Convenience and ease of installation. You do not need a lot of installation materials, you can lay over old coatings (except bitumen).
- Due to the thickness of only up to 2 mm – low weight rolls.
- Good evaporation of moisture without loss of properties.
- High degree of waterproofing. Additional protective coatings are not required.
- Economy contributes to the service life – from 20 years to 50 years, depending on the thickness and type of roofing.
- Resists the effects of any external conditions. The membrane remains elastic, stretched, does not crack, does not lose quality even at low temperatures of operation (down to -30 ℃).
- Fire safety, since no open flame is used during installation.
- Can be installed even in adverse conditions (frost, heat, precipitation).
- Choice of colored surfaces.
- Well amenable to repair and maintenance, but after a competent installation is rarely needed.
Types of roofing membranes: TPO, PVC, EPDM
By execution there are three types of membranes.
- TPO – made of thermoplastic polyolefins. It is a chemical compound of ethylene, propylene and sulfur. A strong carbon chain is created by combining the elements in the right proportions. It is a reliable, waterproof, moderately elastic material. It is well resistant to environmental influences, fungus and cracking. It can be reinforced with polyester mesh.
- PVC – made of polyvinyl chloride. A film material, very flexible and elastic due to the addition of plasticizers. Also provides good waterproofing and resistance to various external conditions. Can be reinforced to increase strength.
- EPDM is from ethylene propylene diene monomers. A compound of synthetic rubber and carbon black, clay, vulcanizers. Excellent resistance to ultraviolet rays, fire, moisture, bends well. Hardly tears, long wear and tear. Reinforced with polyester mesh.
Types of roofing by appointment
When selecting a membrane roof, you need to consider what function it will bear. We suggest familiarizing yourself with the types of roofing materials.
- Breathing. Protects the roof from the influence of precipitation and allows the remainder of moisture and vapor outside.
- Anticondensate. Absorbs moisture that accumulates in the roof. Then takes it outside the structure that prevents excessive moisture from dampening the roof. The basis – polypropylene, surface – moisture-resistant coating.
- Vapor barrier. Protects against internal vapors that penetrate into the roof from the premises of the building. The basis – polyethylene.
- Superdiffusion. The most resistant to rainfall, UV, wind and mechanical damage material. It is flexible and highly durable, prevents physical diffusion (penetration into the material of “extra” particles), removes accumulated moisture outside.
- Polymeric. Provides high moisture protection soft roof, prolongs its life. The basis – polyvinyl chloride.
What a roofing membrane consists of
The so-called “roofing pie” has a layered structure. Membranes are laid on the profiled sheeting or on the concrete base of the roof.
- The base of the roof – steel profiled sheeting;
- The first layer – a vapor barrier of polyethylene, protects the insulation from moisture;
- the second – the heat insulating material (insulator) of mineral wool;
- the third – the mechanical part (fasteners) of telescopic type, fixes the layers;
- the top layer – PVC-membrane, serves directly as waterproofing and roofing.
- the base of the roof – reinforced concrete structure;
- the first layer – sloping expanded clay layer;
- the second – leveling screed of a mixture of cement and sand;
- third – vapor barrier bitumen material;
- fourth – heat insulation material (insulator) of mineral wool;
- the fifth – the mechanical part (fasteners) telescopic type;
- the top layer – PVC-membrane.
Installation work for roofing membranes: preparation for joining
Laying technology has peculiarities with which qualified crews are familiar. We tell you about them.
Membrane coatings are supplied in rolls. For laying, they are rolled out on a prepared surface. It is desirable to level and clean it beforehand, but these are not the main conditions. Remember that you can mount and over the old coatings, except for bituminous. And once again, pay attention to the section “What is a roofing membrane. It details which layers should be a roof before laying the final layer – the membrane.
Unrolled membrane fabrics should not be under tension, as when installing this will create the risk of cracking or shrinkage. Overlaps are created: for EPDM membranes – from 15 cm in width, for the rest – 7 – 12 cm. This laying provides additional waterproofing of seams. The overlap allowance is recommended to take into account when calculating the amount of material to order.
Installation work: attaching membrane panels
Connecting the membranes and fastening to the roof depends on the type of membrane, roof architecture, installation cost requirements.
- Adhesive. A simple but costly way of fixing: you need a lot of adhesive materials (special glue, adhesive tapes). Enough to process the perimeter of the panels, overlapping joints and complex architectural areas – chimneys, gutters.
- Ballast. Available if the slope of the roof is up to 15 °. Membranes filled with stone ballast – crushed stone, gravel, tile waste – about 50 kg / 1 sq.m. roof. If the ballast with sharp edges, on top of the membrane put non-woven material to avoid tearing.
- Mechanical. Available for roofs with a slope of more than 15 ° and not accepting a large weight load. Fix the membrane specialized fasteners with rounded – anchors, laths.
- Heat-welded. The method of welding cloth with hot air – the most popular. A single fabric with welded seams with a width of 2 cm is created. Particular attention is paid to difficult places, protrusions and corners.
How to choose a membrane, mounting method and installation crew
Determine the material and the method of installation is not easy. To do this you usually have to go to the experts. However, this is the right way: a reliable contractor saves the customer from a lot of problems and headaches, takes the risks and responsibility for the project itself.