Synthetic membranes are categorized into PVC membranes (from polyisoboutylene and polyvinyl chloride), the TPO membranes (thermoplastic polyolefin membranes) and EPDM membranes (from synthetic rubber).
The above categories may be reinforced or not and may be of glass fiber, fibreglass, polyester sheets or other synthetic materials. Synthetic membranes are an excellent choice for water insulation on roofs, especially if the roofs have large dimensions, so there is an increased need for the overlapping parts to be strongly welded.
They are also selected in cases where there are standing waters and the inclination cannot be layered anew, as they are particularly resistant to the fatigue caused by standing water.
The great advantage of synthetic membranes is that they exhibit a very high adhesion level on their compounds, a very long lifespan due to their increased resistance to solar radiation and very high elasticity.
The main difference between PVC and TPO membranes is that the latter do not contain plasticizers. Given the absence of plasticizers, the temperature required for the welding of the sheets between the TPO membranes is significantly lower. The absence of plastisizers provides stability in time, increasing both the anticipated lifespan as well as the speed of application. TPO membranes present more powerful mechanic resilience in perforation and injuries than the respective PVC membranes. PVC are always layered above polyester protection textile (geotextile) in order to avoid transfer of plastisizers to their substrate.
EPDM (Ethylene Propylene DieneMonomer rubber) are similar to the inner tubes of bicycle wheels, having additional chemical components with increased resilience in UV radiation. They present great elasticity, very strong weldings between the sheets, exhibiting high dimensional stability.
An EPDM disadvantage is the initial high cost of application which, in the course of time, is balanced out by the long lifespan of the membrane and the fact that it is more sensitive to injuries than TPO or even PVC.
