Roofing materials for flat roofing

In spite of the fact that the roof is called flat, installation inevitably creates a slope of up to 7% for better drainage of atmospheric moisture from the roof. After all, absolutely horizontal roof will last long enough. Changing the cycles of freezing and thawing of accumulated water, stratification of the soil and even the germination of plant seeds brought by the wind are the reasons for the rapid destruction of roofing materials. Therefore, it is important not only to design a flat roof with a minimal slope, but also to choose the materials of the highest quality.

Unlike the classic pitched roof, flat roofing is layered. The supporting structure is filled with an equalizing screed( usually sand-cement), then steam, heat insulation and the finishing layer-waterproofing are laid. In addition, funnel-water receivers( with the device of the internal drainage system) or water intake chutes for drainage of storm and thawed waters into the sewage system are necessarily arranged on the roof. And on the perimeter of the roof for the safety of builders and protection of the roof from the wind parapets are being arranged.

In this case, the roof( with a solarium, parking lot, etc.) installed should have a stronger and more reliable base-overlapping than the non-operated version. Also, for a roofed roof, choose a heater that can absorb large loads( up to 200-250 kg per m2).

The main requirements for roofing materials - work in a temperature mode from -70 to +100 degrees, strength and durability, low flammability, thermal conductivity and hygroscopicity.

Roofing and waterproofing materials for flat roofing

For waterproofing one or more layers( fusion / welding or mastic fixing) are laid with the following roll materials :

• bitumen-polymer( isoplastic, filizol, glass-bit, etc.);
• synthetic rubber coatings( EPDM membranes with reinforcing polyester mesh and without, membranes based on thermoplastic olefins);
• polymer coatings - PVC membranes with reinforcement in the form of polyester mesh;
• bituminous coatings( ruberoid, metal- and foil-isoizol).

In addition to rolls, the following mastic and piece materials are used:

• asbestos-cement slate( obsolete, brittle enough material);
• euroshield or ondulin colored( durable, easy to lay, service life about 30 years);
• roofing metal rebate( sheets or tapes with protective anticorrosive coating for roofing, whose service life is up to 100 years);
• shingles( bitumen, ceramic, cement-sand);
• polymeric mastics, bitumen-polymeric, butyl rubber, bitumen-latex, chlorosulfonopolyethylene( similar to liquid rubber, are applied in several layers in bulk to any flat roof structure, the service life is up to 25 years).

Thermal insulation of flat roofing, materials

Heat losses through the roof of the house can reach 50%.Accordingly, to reduce the cost of heating, to equip a comfortable microclimate of the attic or the upper floor and increase the rigidity of the roof, thermal insulation materials are required, which in turn can be rolled, bulk, flooded( sputtered) or in the form of slabs.

Please note! The thickness of the effective thermal insulation layer is from 2.5 to 10 centimeters. In this case, it is important to take care of the laying and vapor barrier layer, which can serve as a foil( aluminum) substrate or polyethylene film. Builders - professionals advise to lay the vapor barrier on hard ceilings, then fill the filtering material and only then proceed to the insulation.

Bulk heat insulation

Thermal insulation with bulk materials is the most profitable financially, but over time it can "slide" towards the roof slope.

Ceramsite is used for insulation of exploited roofs. In this case, the thickness of the layer that is laid on the geotextile should be at least 5 cm. For a flat roof, claydite with a fraction of less than 32 mm is suitable. This material is capable of withstanding heavy loads, but not the smallest weight. Over the insulation is required a layer of waterproofing, as the material is hygroscopic enough. Guaranteed service life - not less than 50 years.

Gravel backfill is used for insulation of roofs of unexploited. It is often not used in the form of a heater, but as a finishing mound on top of the layers of heat, steam, and waterproofing.

Sand pearlite( expanded, loose) features reduced water absorption, high coating strength, good sound insulation properties. It is completely safe, not flammable, economical. Available with a fraction of 0.16 to 5 mm. The cost is more than 3500 rubles per 1 m3.The average bulk density is 75-100 kg / m3.Also popular is bitumen perlite - a durable material for the insulation of flat roofs with high rates of wind and fire resistance.

Rolled materials for insulation of flat roofing

Rolled materials are all kinds of cotton wool with mineral impurities. They differ in good properties of heat and sound insulation, but they are not environmentally friendly( they use components that are unsafe for health).

1. Glass wool( glass wool) - is produced not only in the form of rolls, but also in the form of plates or mats. The maximum service life is 15 years. Too hygroscopic, requires mandatory waterproofing layer, during installation, skin and lung irritations are possible, the density of cotton wool is low. The cost is from 570 to 1500 rubles per roll / roller.
   

   Use of glass wool

2. Basalt wool .Costly, but very effective insulation for flat roofing. More popular in the form of plates( from 5 to 8 thousand rubles per cubic meter), rather than rolls( from 400 rubles per package).If a cotton wool is added to cotton wool, the insulation has excellent water repellent and sound-resonance properties. Basalt fiber is not combustible( it does not emit toxic substances into the atmosphere during heating), it can withstand a huge number of cycles of abrupt temperature changes( operation up to 50 years).
3. Slag wool is a heater from a mixture of dust eliminator, synthetic resins, as well as mineral fibers( blast furnace, open-hearth, cupola or slag of non-ferrous metallurgy) up to 6 cm in length and up to 0,005 mm in diameter. The material was not widely used in the construction of capital structures due to loss of properties due to sudden changes in temperature and high humidity.

Hot plates

Plate heaters are very easy and fast to be mounted. Most manufacturers produce slabs with an L-shaped edge for better jointing and reducing the likelihood of cold bridges. The slabs are laid in the type of brick rows, observing the take-off between the seams and fixing the joints with adhesive tape( preferably foil).

1. Foam plastic is a widely known lightweight and inexpensive insulation with a thermal conductivity of 0.04 W / mK.Disadvantages of insulation - its fragility, virtually zero vapor permeability, service life of up to 15 years and the ability to break down when applying nitro paint and solvents.
   

   Roof insulation with foam

2. Foamed glass is a foamed molten cellular glass melt( available as slabs, crumbs and pellets).The service life of the material is huge - up to 1 century. The thermal conductivity is low - 0.04 W / m * K.Heater is not flammable, eco-friendly, good soundproofing. The influence of temperatures, pests, humidity is not affected. However, the plates that are pasted on the bituminous mastic, weigh a lot and do not differ in good indicators of impact strength, so it requires pouring reinforced screed.
3. Expanded polystyrene extruded is a heater that is a granule filled with carbon dioxide or air, with the addition of antiseptics. Thermal conductivity not more than 0,027 W / m • K.It has a long service life, resistance to mold development, microorganisms, low hygroscopicity. Lightweight, hard, easy to install. At the same time, the material is combustible, practically vapor-proof. The cost( for example, the warmer firm Thermit) from 95 rubles per unit, 1200 rubles per package, or 4000 rubles per 1 m3.
   

   Expanded polystyrene extruded

Filling heaters

1. Foamed concrete is a heater based on cement and organic foam-forming additives. Durable, light, fireproof, frost-resistant, the density and pressure on the structure are minimal. The thermal conductivity is only 0.05-0.3 W / mK.Casting in the formwork is done by a steam generator.
2. The polystyrene concrete has characteristics similar to foam concrete, but is more dense and heavier. The poured layer is monolithic, dries about a day. The polystyrene concrete solution is prepared on the construction site and poured in by an air blower. Thermal conductivity is not more than 0.055 W / mK.

polyurethane foam is a monolithic coating with a closed cell structure. The thermal conductivity is a record low - only 0.19 W / m * K.Spraying is carried out strictly at plus temperatures of air and absence of a strong wind. Warming is done layer by layer on a prepared( dust-free, dry) surface, each layer is up to 15 mm thick, the number of layers is not less than three. Requires a protective coating, as it collapses under ultraviolet rays.

When choosing a material for roofing, thermal and waterproofing, it is customary not only to compare the price, quality, weight, longevity of materials, but also the roof. An important role in the construction plays the purpose of the roof. So, if the construction of a swimming pool is planned, special attention is paid to the increased waterproofing properties of the "sandwich roof", and when equipping the pedestrian zone, solid boards or road tiles are used as the finishing roofing material. In this case it is extremely important to choose the heater, which will keep the shape and not ask for under any( static or dynamic) loads.

Video - Flat roofing and roofing material