Despite its popularity, is asphalt roofing sheet really a good option for your project? Do you know what the material’s prognoses are when it comes to durability, ease of maintenance, and cost? Find out all about it in today’s article!
What is an asphalt roofing sheet?
Asphalt roofing sheet is a waterproofing method sold in rolls of varying thickness. As the name implies, it is composed of modified asphalt material, to which various materials are added, such as fiberglass, polyester, polyethylene, or rubber, which give the system its own characteristics, such as greater resistance.
In addition to the variations with regard to the added components, the asphalt roofing mats can also differ in the chosen internal structuring, thickness, resistance, and finishing.
The choice of the most suitable asphalt roofing sheet membrane for each project must be made by a specialized professional. However, the most commonly used types of mat are:
- adhered: one of the most common, it can be attached to the surface with asphalt or a blowtorch and is usually applied on slabs, uncovered balconies, or swimming pools;
- floating: used on flat surfaces that suffer great deformations, it is applied without adhesion to the base, disconnected from the substrate;
- aluminized: with a layer of aluminum on top, it is used as the final finishing in areas that cannot be walked on;
- slated: with a self-protection layer of slate, it does not need mechanical protection and is used in non-transitable roof areas with slopes of no more than 30%.
What are the other most used types of asphalt membrane for roofs?
Aluminum asphalt blanket
This model, due to its easily deformable material, is only indicated for roofs where the surface is not subject to heavy loads. Therefore, it should be avoided in regions with hailstorms, as this can compromise its aesthetics.
As advantages, it presents an excellent humidity control and a thermal control. The thermal control keeps the temperature inside the building milder than the variations in the outside climate.
Its installation is very simple and can be done in two ways:
- adherence with asphalt: the asphalt blanket is fixed to the aluminum surface with heated asphalt. When the material dries, it permanently glues the two layers together;
- adherence with a torch: a flame is used to heat the aluminum plate to the adherence face of the mat. The heat liquefies this surface and, when it returns to normal temperatures, it sticks to the blanket. In this case, the torch temperature must be well controlled to avoid permanent damage.
Polyester asphalt mat
In recent years, plastic materials with very innovative characteristics have been developed, such as the polyester polymer. Yes, the same one that is used in fabrics. With the appropriate treatment, it forms a blanket that unites three essential characteristics: resistance, durability, and adhesion.
The polyester structure receives a layer of resin and is thermosetting, so that the waterproofing of the roof lasts much longer, when compared to traditional roofing.
Pre-molded asphalt or polyethylene blanket
Another high-tech polymer, this option is very interesting because it is very resistant to abrasions and impacts due to environmental factors or complementary works. In this way, it achieves greater durability, besides the advantage of being reusable.
In addition, it is considered one of the most versatile blankets, and can be applied on passable slabs, gardens, above vertical walls, storage walls, under water tanks, etc.
What are the advantages of using asphalt membrane?
They protect buildings from humidity
The roof is certainly the structure that receives the most humidity in a building, because it is responsible for draining all the rainwater. Therefore, it must be very impermeable. Asphalt shingles, among the various climate insulation materials, are the most effective materials in this task.
Helps in the preservation of furniture, paintings, and appliances
With this, you will no longer have to worry about the possibility of damage to the structures of your home. Unlike traditional shingles and masonry ceilings, the blankets will not allow drips to appear on your home’s equipment.
They are resistant to traction, punctures, and tears
Finally, we cannot fail to mention one of the great differentials of the asphalt blanket. Other types, such as rock wool, besides not offering good waterproofing, are more sensitive to friction and traction damage, such as punctures and tears. Also, even if there is damage, because it is a reusable material, it is easily repaired.
3 facts about asphalt membrane for roofs that you need to know
Even though it is one of the most popular waterproofing methods, some important information about asphalt membrane is not very well known. Find out what they are!
1. The product’s life span is not long
Contrary to what many people imagine, the useful life of asphalt membrane for roofing is not infinite. It depends on a number of factors, such as the proper specification of the materials, the dimensioning of the slab drainage system, and proper maintenance.
Although some manufacturers inform that the average durability of the product is about 20 years, in general, the asphalt membrane has a useful life with total tightness between 5 and 10 years, since, over time, it loses flexibility and becomes brittle, presenting failures in the fixation and several other problems, such as infiltrations and leaks.
Therefore, when opting for asphalt blanket for roofing in your waterproofing project, it is important to also consider future expenses with its total replacement, since, in this type of coverage, small repairs do not present themselves as efficient or lasting solutions, due to the difficulty of locating the focus of the problem.
2. The costs are high when compared to other solutions
At first, the cost of the asphalt membrane for roofing in the waterproofing project seems not so high, if you consider only the retail price of the product. However, it is important to note that estimating the cost of the project based only on this variable is an important miscalculation.
This is because, to the value of the material, one must add the cost of the need to hire specialized labor. Also, the cost for the need for complete replacement of the material in relatively short periods of time should be taken into account.
In general, waterproofing costs in civil construction are estimated to be between 1% and 3% of the total cost of the work. However, this value can reach a range of 5% to 10% when the project does not achieve its objective and presents defects.
3. The need to hire specialized labor
It is known to be a relatively simple waterproofing system. However, in order for its durability to be guaranteed, the installation of asphalt membrane for roofing requires specialized labor like riverside roofing pros.
This is because the process has a number of particularities, especially with regard to care with amendments and critical points, such as unevenness, which need to be carefully respected by the applicators.
The measure is fundamental to avoid the appearance of leaks and infiltrations that may cause the work to be redone before the time initially planned, which brings a series of inconveniences and extra expenses.
In addition, the waterproofing project needs to be carried out by a specialized professional, such as an engineer or architect. It should be thought over right at the beginning of the work, so that all the details can be planned. The relevant technical standards and avoiding improvised solutions and unnecessary costs should be considered.