Rapid urbanization has turned our cities into concrete and asphalt jungles. Green spaces within cities are dwindling as the demand for buildings and roads is increasing. It has been observed that the temperature within cities is higher than the outlying open spaces. This has resulted in what is known as the “Urban Heat Island Effect”. This dome of heated air mixes with smog and polluted air to create an unhealthy city environment impacting all living things. Further the added heat puts a burden on energy required for air conditioning the buildings. Replacing the hard concrete surface of the conventional roof with a vegetated roof significantly mitigates the “heat island effect.” Further the absorption, retention and controlled outflow of rain water substantially reduces surface water runoffs.
ALYAF GREEN ROOF
A watertight roof is a precondition prior to build up of the ALYAF GREEN ROOF assembly. It is imperative that a good waterproofing system is designed and installed over the roof deck to receive the green roof assembly.
Construction of green roofs in the hot and arid climate of the Middle East region has many challenges. ALYAF with over 29 years’ experience in the region, working closely with GEOfabrics, UK has successfully implemented a comprehensive system to address the challenges in constructing a viable green roof assembly engineered for the tough desert environment.
ADVANTAGES OF GREEN ROOFS
This stored water is essential to keep the agriculture soil moist in the desert environment. ALFDRAIN cups are filled with ALFLITE a light weight aggregate. This would enable retaining water as well as its capillary transmission to the overlying layer
ALFDRAIN has holes suitably located that would enable drainage of excess water.
The bottom half of the ALFDRAIN provides voids through which excess water is drained out of the structure. The voids also help in aeration of the root one.
This is the critical component of the green roof assembly. ALFDRAIN is a cuspated HDPE sheet with engineered perforations and performs the following multiple functions
ALFGUARD ROOT BARRIER
Accounting for growth of roots and their potential to damage thewaterproofing system and the structure is critical. This is accomplishedthrough two steps: One by careful selection of vegetation such thatplants with aggressive root growth are avoided. The second step is touse a robust impermeable root guard.
ALFGUARD HD100 is an impermeable, structured membrane madefrom polyethylene with addition of carbon black as UV stabilizer. ALFGUARD HD100 stops penetration of root growth.
ALFMAT 601M is a purpose designed moisture management matmanufactured from synthetic hydrophilicfibers. ALFMAT A601Mthrough its water retention characteristics ensures that theagricultural soil is continuously fed with moisture.In addition, ALFMAT is an excellent separation and filtration layerto prevent the soil migration.