Technical Area - F.A.Q.
General Preface
Bitumen polymer waterproofing membrane roof covers require periodical maintenance in order to ensure their high performance over a period of time. Every product’s technical properties endure an inevitable decline due to various environmental factors such as temperature (especially in the summer months). Other factors include frost/thawing and meteorological precipitation such as hail etc. In this document the most important points will be illustrated along with the best action to take in order to reduce any future problems. We would also like to underline the fact that not directly following regular waterproofing maintenance may result in the loss of insurance cover due to misuse of the product.
Painting a non self- protecting bitumous surface
Normally the painting of a polymer bitumen membrane is carried out directly on the exposed surface. This membrane must be an APP (plastomeric) membrane as SBS membranes cannot be left exposed to UV rays. The membranes also require mineral protection (slated membranes) or a heavy protection (cls or other cover). Where traditional membranes modified with APP are concerned these membranes must be painted with the correct substance (POLYVER ALU) which is compatible with the bitumous matrix of the product. Usually the paint has a highly reflective quality and often has an added aluminium pigment in order to maintain the membrane temperature as low as possible; therefore it is not advisable to use dark colours.
Slated membrane maintenance
Self-protecting slated mineral membranes are often chosen for visible waterproofing in order to avoid painting maintenance. These membranes, apart from ensuring watertightness thanks to the layer of mineral slate on their surface, are not subjected to UV rays and therefore the bitumous mass does not suffer.
The granules are usually made with flakes of natural slate therefore a slight chromatic difference can be seen due to the nature of the product. The quantity of slate applied is approximately 1kg per m² and an initial granule loss at the beginning of a project is perfectly normal, normally there is a tolerance of up to 15%, which occurs because not all the slate flakes manage to penetrate the bitumous mass during production.
Walking on bitumous membranes
Polymer bitumen membranes whether smooth (non-self-protecting) or slated, ARE NOT TO BE WALKED ON. In summer the bitumous mass tends to become softer, therefore it is easily damaged (especially on slanting roofs).
Snow on roofing surfaces
Snow on roofing requires some attention; in fact the presence of a snow covering for periods of time could cause minor malfunctions due to the rise in humidity and possible seepage
Roof waterproofing surface curling
Polymer bitumen membranes applied with traditional methods (propane gas flame torch) can be applied in different ways, depending on the surface they need to be applied to.
These surfaces can be:
“totally free” (independent laying)
“Partial laying” or partially glued parzialmente al supporto;
“Total adherence laying” (all surfaces).
In all three cases both the overlap and the perimeter of the covering are soldered to the support. Depending on the type of laying used the membrane will be more or less free to move for any eventual temperature or insulating system changes etc.
Water or air bubbles on roofing surface
The presence of water or air bubbles on waterproof covers is a fact that can occur in some particular circumstances, such as in the case of thermal insulation and the absence of an adequate vapour barrier. In the latter case the vapour may rise up and meet the membrane (notorious for being scarcely breathable to water vapour) and bubbles can form, at low temperatures, which then condense into water. Another problem can occur when the concrete is not left to set long enough and being waterproofed immediately it holds on to the water still present inside it.
Delamination of self-protecting membranes with copper or aluminium leaf
For many years, with the aim of providing an aesthetically pleasing polymer bitumen membrane, self-protecting metallic membranes have been produced with a metallic leaf. This leaf can be in natural or coloured aluminium or copper. These products are surely high quality but require some particular attention in order to guarantee their longevity.
Maintenance of industrial factory roofing
Here, reference is to those industrial buildings in which production activities are carried out, which by their nature can emit smoke or aggressive substances into the atmosphere, which could damage the bitumous mass of the membrane.
The effect of hail on bitumous membranes
Hail is a meteorological phenomenon which concentrates on one area and is often very violent. It occurs due to large temperature differences in air masses. Sometimes hailstones can be of ample dimensions, in these cases hailstones cause an intense mechanical degradation to the membrane. Hail is often accompanied by a rapid and violent drop in temperature which can make the membranes more fragile. In circumstances like these hailstones can break the membrane itself. Choosing a technically higher quality membrane eliminates or reduces the destructive effects of hail. The high quality membranes or elastomeric (SBS) are much more resistant to dynaminc impact.
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