Bitumen felt or liquid membrane? 5 common waterproofing situations and the appropriate solutions for each of them.
Flat roof being waterproofed
Nowadays, when the need is to waterproof a flat roof it is possible to choose among many innovative liquid products. They can be solvent-free or water based and made with exclusive selected resins. Also, in the market, there are high performance bitumen-polymer membranes. We can certainly say that there is no shortage of solutions when choosing the most adequate one for your roof. In front of all these choices, how do you know what is the best option to pick?
Bitumen-polymer membranes and liquid membranes are used for roof protection, to waterproof terraces, ground walls, sanitary rooms, parking lots, civil and industrial surfaces, and so on. All of the above said applications have the same goal: to create an effective barrier to water and rising damp.
They can also be used to maintain and restructure the old waterproofing layers and structure, which are subject to the effects of time, and the aggressive action of atmospheric agents and pollution, when talking about roofs and outdoor places.
Before choosing the appropriate waterproofing product for a specific situation, especially when doing renovation or maintenance works, it is fundamental to carry out a careful analysis of the state of the roof.
How can we guarantee an effective waterproofing and a lasting effect over time? And should we use bitumen felt or liquid membrane?
Let’s look at 5 different common situations and the most appropriate action!
1. GEOMETRICALLY COMPLEX SURFACES
A flat roof does not necessarily mean completely smooth surfaces, free from any interference. We could find elements such as skylights, antennas, pipes, aerators and emerging objects, all potential obstacles to an effective waterproofing. In this case, the use of a liquid membrane like Winkler One is highly suggested. As a matter of fact, due to the nature of the product, which can be applied with a roller or brush, it is easy to reach every point of the surface.
Due to the irregularity of the surface, the use of a polymer-bitumen membrane, although still effective, would be much more complicated. We would often need to cut and shape the membrane itself, thus increasing the risk of problems related to “continuity” of protection. This, in turn, could lead to infiltration of water. On the other hand, if the roof surface is linear and unobstructed, the laying of the bituminous membrane is just as effective.
2. MAINTENANCE OF OLD BITUMINOUS FELTS
In renovations, the choice of the waterproofing product must be done only after a meticulous analysis and definition of the roof surface‘s condition.
Designers and installers must focus their attention on: old deteriorated membranes, loss of adhesion to the support caused by the action of atmospheric agents, structural problems in “delicate” areas of the roof. For example where the drains, the ducts, the joints and railings are located.
If we have big and free surfaces, we can apply polymer-bitumen membranes, even if they overlap to the existing membrane (provided that it is in good condition). However, to ensure a perfect waterproofing in this case, it is necessary to apply a water based bituminous adhesive, which will favour the perfect adhesion between the two membranes, thus avoiding the risks caused by the different movements of the two membranes.
This technical solution allows laying without the use of flame. If the surface is in screed, the bituminous membrane is the ideal solution. Otherwise, if the surface is irregular, it is better to use the liquid membrane, even on the old cover.
3. FLAT ROOF VS TERRACES
In the past, flat roofs could be waterproofed and “forgotten”about, except for the occasional maintenance work. However, in the modern world, it is common to transform these types of roofs into terraces.
This can cause problems to the waterproofing because granular bitumen felts cannot always be walked on without compromising their waterproofing action. Luckily, modern technology offers effective solutions, such as highly resistant liquid waterproofing products. They are applicable in the most extreme weather conditions (from 0 to 45 Celsius). They can also be used on concrete screeds, even if they are not completely cured yet or on damp substrates. These products are formulated with special resins and don’t contain neither water nor solvents. They can withstand up to 4 bars of counter pressure, and above all they do not fear possible damage from trampling or the positioning of deckchairs, tables and chairs. The drying times are very fast. These innovative liquid membranes can also be applied directly over existing modified bitumen felts, including granular ones.
Flat roof after being waterproofed with a liquid membrane
4. IF THE TORCH CANNOT BE USED
Sometimes, the laying of bitumen modified felts cannot be done using the traditional torch. For example, in areas where the use of open flames is forbidden or when the surface is made up of wooden elements or other materials that are sensitive to heat. It can also happen that the safety rules prevent the use of a gas tank on a specific site.
At that point, our choice would fall between adhesive polymer-bitumen membranes like Winkler Winglue , or liquid membranes.
The adhesive polymer-bitumen membranes are also known as “cold systems” even if hot-air appliances and other specific equipment are used for correct installation (to ensure the tightness of the side and head joints).
This product, which guarantees excellent adhesion to the substrate and is easy to install, is recommended for very regular floors, with little interference or inhomogeneity of the surface. Furthermore, the laying of adhesive membranes along vertical walls must include mechanical fixing, to avoid the risk of “slipping” of the membranes.
Modern technologies and intervention techniques help the applicators in many situations. The new liquid membranes, thanks to their versatility and simplicity of application, are a valid alternative, above all where the existing membranes already cover the surfaces.
These products are tough and performing, they resist to water stagnation and ultraviolet rays. They can also be applied on ceramic floors with excess of humidity, on concrete screeds, on tiles, wood and metal. Lastly, they are ready to use and do not require further processing or the use of primers and any reinforcements.
5. AN ECOLOGICAL CHOICE
The use of products that have a particular attention to the environment and human health is increasingly common in the construction field. Thanks to technological research, indeed, designers and professionals can make such a choice!
Modern waterproofing focuses on the use of real systems instead of simple individual products. These “systems” are designed to interact perfectly with each other, in order to offer the maximum effectiveness.
All of the above led to the creation of high-performance thick solutions in the field of bituminous membranes, which also perform as barriers to vapor and have excellent mechanical strength.
At the same time, liquid membranes have undertaken an innovative development too. The newest are water based, solvent-free, and formulated with highly selected resins. These elements allow the products to provide excellent waterproofing performances, resistance to various stresses as well as a high protection against UV rays (saving the cost of buildings in the hottest months). Winkler Wingum Plus H2O is a product with those features. In addition to that, liquid membranes protect the surfaces, and in some cases they can even repair structural anomalies in the surfaces themselves.
As a conclusion, after looking at these 5 different examples and the most suitable way to identify the appropriate solutions, we’ve put together a list of principles to be considered when choosing the ideal waterproofing product. Winkler’s product portfolio includes both bitumen felt or liquid membrane solutions, which make any waterproofing work simple, quick and safe, allowing considerable savings in time and resources.
