Commercial roofs are generally flat and can be classified according to destination, construction type and materials used for waterproofing. There are civil or industrial terraces, circulating or non-circulating, load-bearing for heavy, medium or light loads, as well as terraces with or without vegetation. In establishing the technology for flat roof waterproofing, the constructive type of the roof`s infrastructure and superstructure is important.
Bituminous waterproofing
Traditionally, flat roofs have been waterproofed using bitumen. In the past, this material was poured in a hot state over the roof, incorporating different other materials that reinforced the final result. This solution has been able to cope for a very long time. However, the lack of bitumen additives and the poor quality of the embedded inserts cause the bitumen layer to crack over time. Fortunately, technological evolution and human imagination have made the roofing industry evolve significantly, especially in more recent years. At present, the old bituminous waterproofing has been replaced by the installation, in one or more layers, of waterproof membranes. These membranes are added in the bituminous structure with different additives that ensure elasticity, malleability, resistance to large temperature variations, to ultraviolet radiation, to plant roots, etc. The improved composition of new roofing membranes also ensures high resistance to stretching in any direction, transversely and longitudinally.
Waterproofing layers occupy different positions in the section of the roof`s structure. roofing Boca Raton installers affirm that they can be installed above or below the thermal insulation (e.g. the inverted thermal insulation of flat roofs). They can also be installed over or under superstructures (cement screed etc.). Last but not least, waterproofing layers can be completely or partially glued to the support (e.g. diffusion membranes, vapor barriers).
Newer technological solutions for flat roof waterproofing include:
- Application of mastic. Application of sodium bentonite products
- Application of cold membranes, such as polyurethane, acrylic or epoxy
- Installation of elastic or plastic membranes (EPDM, PVC, TPO)
- Different combinations of rigid polyurethane foam with liquid UV protection membranes
- Different injections of synthetic resins in the superstructure of the roof
- Introduction of various additives in the composition of concrete, cement screeds and plasters
All these represent technologies that come to compete with the classic bituminous waterproofing of flat roofs. However, each technology responds, to a greater or lesser extent, to customer requirements. Thus we can criticize liquid membranes for the less thickness of the layer (approx. 2 mm); EPDM, PVC, TPO membranes for allowing vapor condensation; rigid polyurethane foam for not resisting well to UV exposure; mastics, injected resins and waterproofing additives for being expensive materials in relation to the size of the application surface.
The combination of technologies is the solution of achieving optimal flat roof waterproofing, from the point of view of several criteria, technical and economic.
Green terraces
Green terraces have some particular features compared to regular flat roofs. In addition to the classic waterproofing, green terraces must contain the following layers:
- Vegetal layer
- Vegetative substrate
- Geotextile water filtration membrane
- Drainage and water retention layer
- Anti-root membrane
- The thermo-hydro-insulating system of the terrace
A green terrace system is associated with floating alleys (tiles or decks mounted on adjustable plots). This ensures proper water drainage and creates a particular environment.