What is bitumen, not only builders know, but also many consumers. This material was used several decades ago everywhere for covering small farm buildings, arranging a moisture barrier between the foundation and the wall of buildings, and for many other purposes. But pure bitumen is not the best option for the production of roofing. After all, it lends itself to aging, becomes brittle and hard under the influence of oxygen and sunlight. As a result, cracks appear on the surface, and it loses its waterproof function. To get rid of these shortcomings, oxidized bitumen is used for the production of roofing.
Production Features
The production of bitumen is a complex process that takes place on the territory of oil refineries. The raw material is oil, and not just one grade, but several that are carefully selected. The quality of the finished product depends on how high-quality the starting material is.
The production of oxidized bitumen is a forced process and is carried out on a special installation. In it, the feedstock is heated and oxygen is passed through it. The feedstock may be fuel oil, tar, cracked residues, semi-tar, or a mixture thereof.
Benefits & Features
The consequence of the oxidation process will be the acquisition by the product of characteristics important for operation, which include:
- Change the heat resistance of the coating from the initial +45 degrees to the final +120 degrees.
- Thanks to the shutdown of all chemical processes, the roofing product acquires the necessary rigidity.
- Higher fire resistance than the non-oxidized analogue.
- Lack of emission of vapors and unpleasant odors when heated.
- Thanks to the improved quality, basalt granulate does not crumble from the surface.
- The coating retains its appearance, does not swell and does not crack.
- Improved wind resistance. Due to the fact that the rigidity of the material has increased, the coating easily resists even the strongest winds.
The oxidation process will not end there - it will continue after the installation of the roof for a period during its operation.
The disadvantages of oxidized bitumen
Unfortunately, the oxidation process gives the coating some disadvantages:
- Fragility at subzero temperatures - the material hardens in the cold, becomes hard. Therefore, it cannot be used for installation. This is a significant minus for professional builders who have to work not only in the summer.
- Due to the fragility of the canvas, if necessary, it is difficult to repair it in the cold - at the slightest load, for example, it is enough to stand on the roof, it begins to crack and break.
Modified Bitumen Production
What is modified type bitumen? This is the name of the material in the initial mixture of which a certain type of modifying substance is added. This is necessary so that finished products for roofs can withstand various weather influences. What does the addition of modifiers give? Mixing bitumen with the polymer added in the correct proportion gives the final product properties that are important for operation:
- UV resistant.
- Good adhesion.
- The ability to keep fit well.
- Resistance to sharp changes in temperature.
Many consumers are wondering if the added polymer is harmful to humans and the environment. The following fact testifies to how safe the thermoplastic is - after several years of operation, fungi, moss and other biological organisms begin to grow on the coating surface. To destroy them, it is enough to treat the surface with any substance, the basis for the creation of which was copper sulfate.
Comparison of the characteristics of oxidized and modified bitumen
The properties of oxidized bitumen and sbs-modified are largely the same. This is a long-term operation, excellent appearance. But there are differences. To understand which of the materials has the best performance and is more suitable for a particular object, it is necessary to compare their characteristics and consider the differences.
Description of characteristics | Oxidized bitumen | Modified bitumen |
Temperature range at which operation is possible. | -55 ° C to + 120 ° C. | From -25 ° to + 120 ° C. At lower temperatures, coatings begin to crack and crumble. This leads to a violation of tightness and a change in the appearance of the roof. |
Adhesion. | High adhesion. Thanks to this, the material has excellent wind resistance - even with a strong wind it does not fall off the roof. In addition, the granulate adheres perfectly to its surface. | Minimum adhesion, due to which granulate may crumble. |
Quality. | The final material is of high quality, independent of the quality of the feedstock. | The quality of the finished roof completely depends on the quality of the raw materials. If it did not possess the required quality in order to achieve good quality of the final product, manufacturers have to use various stabilization additives. |
Flexibility | High rate | High rate, but only at positive temperatures. |
The use of chemical modifiers | Not provided | Used to extend the life of the roof. |
Environmental friendliness | Contains no harmful or chemical substances. Therefore, it is considered safe for humans and the environment. | May release harmful substances, albeit in small quantities. |
Conclusion : although modified bitumen is cheaper, according to various indicators, it is slightly inferior to the oxidized analog.
Mounting Features
As they say about
flexible tiles, reviews of experienced builders, if the installation of each type of coating was carried out correctly, there are no significant differences in the behavior of the roof. But there is one important nuance. It is necessary to choose and install a coating of both materials, taking into account their characteristics and properties. So, in the summer it is more convenient to work with modified bitumen - it has greater heat resistance and has proven itself at high temperatures. If an oxidized analogue is used for installation, it is better to work with it in the winter. It also remains flexible at very low temperatures.
Conclusion: you can work with any material, if the work is carried out according to the manufacturer's recommendations and strictly follow all their requirements, the roof covering can be used for many years, while maintaining its characteristics.
And what do the owners of houses covered with similar material say about flexible tiles? The most important thing that each of them says is the high aesthetics of the coating and its reliability. After several years of operation, the surface remains intact and performs its function.
Types of Modified Bitumen
Depending on the type of modifier to be added, there are two types of modified bitumen:
- SBS (rubber bitumen). To obtain it, rubber is added to the bitumen mass. Due to this, the mass changes its structure at the molecular level. A bitumen roof made of a material has higher flexibility and strength at subzero temperatures, and also acquires the ability to repeat all surface bends and even after significant stretching to return to its original state.
- APP. This is the name of the mixture in which the polymer (atactic polypropylene) is added. Due to this, the finished web changes its ductility with temperature changes (the higher the temperature, the higher ductility and vice versa). The added polymer has a low cost. Therefore, the bitumen roof obtained with its use is lower than with SBS additives.
Advantages and features of modified coatings
SBS-modified material:
- It has a large elongation coefficient - the canvas can be stretched to a length greater than the original 20 times, and at the same time it will not collapse, but will remain intact. Oxidized bitumen has a much lower rate.
- At temperatures below zero, the web retains flexibility and elasticity.
- When bending, cracks do not appear on the canvas, even if the ambient temperature is below zero.
APP-modified material:
- Changes ductility with temperature. The higher the thermometer, the faster the ductility improves, and vice versa - when the temperature decreases, the flexibility of the coating decreases sharply.
- The cost of coverage based on AMS modifiers has a lower cost than the SBS counterpart.
The disadvantages of a modified roof
The coating with APP modifiers is not intended for use in regions where the temperature in winter drops below -25 degrees. He begins to crack and crumble. When coating the roof, it is necessary to work with it carefully. The material is completely inelastic, and if stretched, it does not return to its original state.
Due to the variety of roofing bitumen materials on the construction market, each consumer can choose an option at the most suitable price and with those characteristics that suit him.