Good to know
Root overgrowth protection
Well-functioning root penetration protection is essential for both intensive and extensive greening of roof surfaces. A protection system is needed to permanently prevent damage to the roof insulation by penetrating roots. For this purpose, single-layer or double-layer materials are used. Single-layer and double-layer materials are usually resistant to root overgrowth. They are made of plastics in the form of films or roofing membranes. Double-layer coverings are made in the form of a base layer with a minimum thickness of 4 mm and a top layer with a thickness of at least 5 mm.
Both layers are produced with the use of bitumen modified with SBS polymer. The resistance to root overgrowth in bituminous products is ensured by the addition of a special chemical agent or a copper foil insert. Roofing materials should be installed in accordance with the manufacturers’ instructions and in accordance with the applicable standards. A necessary condition for installing a green roof is 100% tightness of the roofing!
Preventive fire protection
- intensive greening, regularly irrigated and maintained, and usually characterized by a thick substrate layer, is treated as a flame resistant cover,
- extensive greening should be assessed as sufficiently resistant to transferred fire and radiant heat if it has the following characteristics:
- established mineral composition of the supporting vegetation layer with a thickness of min. 3 cm
- forms of vegetation with low fire load
- for larger green areas, the so-called fire barriers (gravel strips, concrete slabs) at a distance of 40 m from each other are used
Due to exposure to wind, buildings are loaded with pressure and suction forces, the intensity of which depends on the direction and strength of the wind, as well as the shape and height of the building. Wind loads occurring in the area of the roof can cause damage both during construction works and on the finished roof.
The roof area has been divided according to its degree of exposure to wind loads into three areas:
- corner area with very high load
- edge area with high load
- central area with light load
Each area should be properly secured with the use of appropriate measures. In the corner area and on the edge of the roof, gravel bands or concrete slabs should be used.
The existing correlation between the form of greening and the thickness of the vegetation layer is shown in the diagram below: