High-quality waterproofing is the perfect solution to the problem of roof leaks and moisture. Depending on the material from which it is made, waterproofing can be of three types: bitumen, polymer or cement. Bitumen waterproofing is the most common, as it has many advantages: easy installation, high level of insulation and strong resistance to harmful atmospheric conditions (wind, rain, strong sunlight, etc.).
WHAT IS BITUMEN?
Bitumen is a construction and insulation material with universal application. It can be used both as a roof covering and as a roof waterproofing – especially on flat roofs. Accordingly, the forms in which the material is available are equally diverse.
PROPERTIES AND AREAS OF APPLICATION OF BITUMEN
Bitumen (also called tar) is a mixture of petroleum with various organic materials. It is essentially a natural material that has been known to mankind for a very long time. Bitumen putty was used as early as 6700 BC for modeling sculptures and as a waterproofing material.
Due to its diverse application possibilities (in roofing or road construction, etc.) and in order to meet the high demand, bitumen is mainly produced industrially. The largest amount of refined bitumen is used in construction - mainly as an ingredient in products used for flooring and roofing. On average, 85% of all bitumen is used as a binder in asphalt on roads. It is also used in other places requiring reliable pavement such as airport runways, parking lots or pedestrian walkways.
10% of bitumen production worldwide is used in roofing due to its invaluable waterproofing properties.
The remaining 5% of bitumen is used mainly for bonding and insulation in a number of construction materials such as pipe insulation, paints and others.
WHAT ARE THE ADVANTAGES OF BITUMEN?
Depending on its composition, bitumen can be plastic, elastic or quite hard. It is also used in liquid form. Based on these material properties, bitumen is used in many areas as a useful building material, which is very good and easy to process. To this can be added the fact that bitumen as a natural product is well tolerated by people and nature and meets all environmental standards. For these reasons, it should not surprise us that bitumen has become one of the main building materials today.
WHAT BENEFITS DOES BITUMEN BRING?
Nowadays, this material is used both for covering and insulating roofs and in road construction for connecting joints. The benefit of applying bitumen is due to the fact that the chemical composition of the material allows for effective sealing and insulating the roof against moisture. Sulfur, nitrogen, oxygen and traces of metal form the water-insoluble consistency of bitumen. Only at high temperatures does the process of decomposition of this composition begin. Due to the various substances contained in bitumen, it is not possible to indicate its exact melting temperature, but rather a melting zone is spoken of. At the same time, the oil-containing material is resistant to alkalis and acids that do not oxidize. However, this is exactly what complicates the removal of bitumen once applied.
WHICH BITUMEN MATERIALS ARE SUITABLE FOR ROOFING?
Depending on the requirements, there are different materials to choose from when covering a roof with bitumen. Corrugated bitumen panels, for example, are a compact and cost-effective method of covering a roof. They are mainly used for covering sheds, outbuildings and canopies.
However, there are also decorative forms of bitumen that are suitable for covering residential buildings. Bitumen tiles are produced in various traditional forms, which in appearance are almost indistinguishable from the original. They are sold in rolls or sheets that are cut and laid. In this case, it is especially important to work precisely and correctly to seal and waterproof the joints and joints between the individual sheets.
WHAT CAN BE INSULATED WITH BITUMINOUS COATING?
With the help of bitumen coating waterproofing (bitumen coating or paint) any possible materials can be insulated and thus protected from moisture and water penetration. An important area of application of bitumen coating is the waterproofing not only of roofs, but also of foundations, bases and other structural details in contact with the soil. The liquid building material should be applied to a completely clean and dry surface, thus ensuring long-term waterproof properties.
Another method for long-term sealing and waterproofing is the thick-layer application of bitumen paste or bitumen putty. In this case, the black material is enriched with artificial polymers and is applied in several layers on the well-cleaned surface. It is very well absorbed by cracks and splits in the base and is very suitable for small repairs of leaks, roofs, gutters, etc., as well as for repairing punctures in bitumen waterproofing and membranes.
HOW IS THE BASE TREATED BEFORE LAYING THE WATERPROOFING?
In order to obtain good adhesion and for bituminous materials to adhere optimally to surfaces such as metal, wood or concrete, it is necessary to pre-treat the base with a bituminous primer. It is a bituminous-based primer coating that is applied before soldering or gluing the base material. Bituminous primer vapors are flammable and therefore should not be used in closed rooms that are not well ventilated. After the base has completely dried, the application of the main bituminous coating can begin.
The oil-containing material is most often used on flat roofs. Even with optimally performed installation work and professional maintenance of the flat roof, after a certain period of time there comes a time when it needs to be renovated. However, before the renovation work itself is carried out, the condition of the roof must be very carefully checked, analyzed and all stages and materials - well planned.
WHAT DO WE NEED TO KNOW WHEN INSTALLING BITUMEN MEMBRANES?
When installing bitumen membranes for waterproofing purposes, attention must be paid to the surfaces on which they are laid. When installing bitumen membranes on an old waterproofing layer, you should know the following:
- The surface on which the bitumen waterproofing will be applied must be flat and smooth. If there are any roughnesses and irregularities, a trowel is used to level and smooth them. All cracks are filled with cement mortar. Before applying the material, the surface must be clean and dry.
- A bitumen primer is applied to the area where the insulation will be applied. Its presence is especially important for the places where the membranes will be connected. The primer plays a very important role by preparing the surface and enhancing the adhesion and good adhesion of the material. It is left to dry between 2 and 24 hours.
- Provided that you want to preserve the old roof waterproofing, it can be used as a base for the new one. Damaged areas must be removed. If air bubbles have formed, they are cut out.
- Laying bitumen membranes on wooden surfaces is done using nails. It is good if the nails have a wide head. This will protect the wooden surface from direct heating from the burner, with the help of which the gluing is done.
- Bitumen membranes are also used on concrete substrates. The previously dried and cleaned surface is primed with a primer where the waterproofing membrane will be laid. The primer must dry well before laying, which is done by heating both surfaces.
- When the surface on which the membranes are placed is insensitive to heat, there are two options for bonding. The first is by gas-flame method. The second is by laying fiberglass reinforcement, in which bonding occurs without heating. This method of bonding is often used in waterproofing flat roofs of panel blocks and old residential buildings. Bonding the membrane rolls in the overlap area using a trowel or other type of spatula is not recommended due to the fact that the membrane can be damaged in this way.
- It is also wrong to overlap the bitumen membranes by only 2-3 cm, because this is not enough. To achieve sealing, 10-15 cm is needed.
- When laying two or more layers of bitumen membrane, it is extremely important that they are well bonded to each other. The effectiveness of the multi-layer system is guaranteed only when it is laid correctly, and each subsequent layer is correctly laid and bonded to the previous one.
Bitumen waterproofing systems can also be applied to any vertical surfaces. They are re-installed by gluing and heating.
WHAT IS REQUIRED FOR FLAME GLUING?
The rolls of bitumen waterproofing, such as those offered by us, are applied by gas flame bonding. Here is what you need for it: a gas burner, complete with a gas cylinder, a reducing valve and a hose (at least 10 m), a trowel with rounded edges, a knife and gloves.
The tarpaulin is pressed against the base and along the overlaps. The edges of the overlaps are shaped with a trowel so as to obtain a watertight connection. When performing waterproofing in two layers, the second is offset from the first by 50 cm. The overlaps must not coincide with those of the previous layers.
Poorly bonded areas are further treated by carefully lifting the overlapping edge with a preheated trowel and pressing it back against the substrate to create a watertight bond. Unbonded edges should never be repaired by heating the tarpaulin from above.
It is prohibited to glue the rolled waterproofing material with a gas burner onto board cladding!
WAYS OF ARRANGEMENT OF MEMBRANES
When arranging bitumen waterproofing, the membranes should be laid by connecting them to each other, starting from the water drains or from the roof cornice.
- Lateral overlap of the membranes: this creates a full-length joint between two membranes. The membranes must be carefully glued until a strip of the mixture of about 1 cm in size has seeped out and protruded along the entire length of the overlapping parts of the joint. The width of the overlapping parts must not be less than 10 cm.
- Butt-lap of the membranes: this is how the shorter sides of the membranes are joined. They must also be processed very carefully. The membrane must be heated sufficiently until a strip of material of 1 cm in size has flowed through. The width of the butt-lap surfaces must not be less than 15 cm. In places where spot-glued bitumen membranes are laid, they must be completely glued to the surface around the butt-lap, at least 1 m on both sides.
- Full adhesion installation: both the membrane and the underlying substrate must be heated, with emphasis on the membrane. The already installed membrane must also be treated with a direct flame where the surfaces overlap.
- Butt overlap by cutting at 45 degrees: the butt overlap of the upper and lower parts of the membranes must be cut at 45 degrees, with a 10-centimeter piece removed from the membrane for better contact with the laying surface.
- Two-layer waterproofing coatings: if it is necessary to apply another layer, it must be applied in a staggered manner over the joints of the first layer and must be fully bonded by heating.
- Butt-lap of mineral-coated membranes: when butt-lapping mineral-coated membranes, the lower membrane needs to be heated in order to extract the bitumen mixture to the surface. This is done by continuous heating and guarantees perfect adhesion of both ends. The bitumen mixture of the upper membrane also needs to be heated.
BITUMEN INSULATION IS LAYED IN THE SUMMER
In the name of maximum customer awareness, we will introduce you to some important tips regarding bitumen waterproofing. Here they are:
- Work with bitumen insulation should be carried out during the summer months of the year
It is very important to choose the right time of year to insulate your apartment building or house, as well as any public building that needs it. It is important that the weather is dry and warm, so the months of July and August are most often recommended. In some years, there are excellent conditions in June and September, but be careful with the forecast and choose a time when there will be no surprises.
- It is important to ensure that rainwater can drain away: part of a job well done is to ensure that rainwater can drain away easily and quickly. Even the best quality work can be put to a serious test if huge amounts of rainwater start to collect on the roof of the building and cannot drain away quickly. This creates a risk of leakage even through otherwise very well-placed waterproofing. However, the roof of a building is not a swimming pool and is not designed to collect significant amounts of water.
- Special attention should be paid to all curves, chimneys, and the like. Experts emphasize that the bases of chimneys and any other place where smaller or larger curves and thresholds are observed must be very carefully sealed.
LIQUID WATERPROOFING CAN BE PERFORMED IN COLD WEATHER
The technology for laying continuous waterproofing from liquid materials is extremely easy to learn and implement – applying the materials with a brush, cutting and laying the strips of reinforcing fabric. This method of implementation particularly greatly facilitates the work when laying the waterproofing on vertical surfaces, as well as on more complex relief of the base. In addition, the insulation can be performed at temperatures down to about 0°C, which can be a great advantage for builders who are late with the deadlines. The waterproofing can also be applied to damp substrates, including freshly demolded reinforced concrete elements and, accordingly, on very fresh concrete. If necessary, the waterproofing can also be laid directly on solid, pressure-resistant, thermal insulation boards (XPS), because the method does not require heating.
ADVANTAGES OF LIQUID WATERPROOFING
In recent years, the demand for liquid waterproofing, which is applied by smearing and has a number of advantages, has been growing. They are waterproof and non-combustible materials based on high-quality elastomeric resins.
Liquid waterproofing is a multi-layer system that is created on site by successively applying several layers. If necessary, a reinforcing mesh or polymer or glass fiber fabrics can be embedded between the layers. After applying the material, a waterproof membrane with high elasticity, without joints and cracks, with high resistance to temperature amplitudes is obtained.
HOW IS LIQUID WATERPROOFING APPLIED?
The base must be sound, well cleaned of dust, oils, unstable materials and other adhesion-reducing substances. The base must be primed and the primer must dry. In the joint area, “compensation strips” are applied (bitumen tarpaulin or polymer foil with a width 4-6 times greater than that of the joint).
The liquid waterproofing is applied in several layers with a brush or roller. To strengthen the waterproofing layer, it is reinforced with a fiberglass mesh or polyester veil, as appropriate. Immediately after applying the first layer, the reinforcing glass mesh is placed and pressed to the base with the help of a brush so that there are no folds. Then a little of the insulating composition is applied again so that the mesh is completely covered. Wait for the complete drying of the resulting reinforced layer. Then apply 2-3 even layers. It is of paramount importance to wait for the complete hardening of the applied layer before applying the next one. Each layer is about 1.5 mm thick. When applying a thicker layer, cracks are possible.
The applied coating must be protected from rain and frost until it has completely hardened!
