Comparing a roofing membrane with a waterproofing memb rane is a relatively common topic among construction professionals, especially those who have not yet tested the performance of a waterproofing membrane. Both systems have played (in the case of roofing membranes) or have played (in the case of roofing membranes) an important role in the protection of roofs and surfaces.
The roofing membrane, a traditional method used for decades that stood out for its accessibility and initial effectiveness, eventually began to show limitations. The evolution of waterproofing systems with the appearance of waterproofing sheets has made it possible to offer much more efficient and durable solutions adapted to current construction needs.
Today, we analyze the differences between traditional roofing membranes and waterproofing sheets, highlighting their advantages, disadvantages and the best solution for today’s waterproofing.
Table of Contents
What is roofing felt?
Asphalt roofing membrane is a waterproofing material that belongs to the category of asphalt waterproofing solutions and serves to prevent leaks. Asphalt waterproofing uses materials derived from asphalt to create a waterproof barrier to prevent water seepage.
What types of asphalt waterproofing are there?
There are three types of asphalt waterproofing:
Asphalt Waterproofing Paint
Asphalt waterproofing paint is a product that can be applied on wood, metal surfaces, fiber cement and cementitious materials. Although it can be used as a primer and adhesive base, its waterproofing function is the most used, although it requires several coats and even the application of geotextile products as reinforcement.
Bituminous or bituminous bituminous roofing
Based on the use of bituminous products, this waterproofing roll waterproofing is used on decks, roofs and foundations to protect the structure from moisture and seepage. It is composed of pure oxidized asphalt and a base of organic felt or fiberglass. It is usually installed with a blowtorch by thermowelding in overlaps.
Reinforced Asphalt Sheeting
Similar to the previous option but with a reinforcement for greater strength. To obtain a higher waterproofing capacity, it usually requires an additional layer, which makes installation more expensive. Unlike the waterproofing membrane, the
What are the main disadvantages of roofing felt?
This waterproofing solution has certain disadvantages that have been accentuated over the years.
- Durability: Currently, the useful life of asphalt waterproofing is a maximum of 5 – 7 years.
- Degradation due to exposure to extreme climates, for example under continuous sunny weather conditions.
- It is common for cracks to appear, causing water seepage due to the combination of the climate and the structural movements it must withstand.
- Slower, dirtier and riskier installation process, using a blowtorch and butane, e.g. on asphalt fabrics
- In certain roofs it does not guarantee watertightness.
- Regular maintenance: it requires repairs and may even need to be reapplied, so even though it is economical in the short term, the investment is the same in the long term.
Feel free to read more information on our blog about the prices of waterproofing systems.
Differences between roofing membrane and waterproofing membrane
Although roofing felt has been a classic method of protecting roofs and surfaces, its limitations in durability, flexibility and resistance to temperature changes and solar radiation have made its effectiveness increasingly questionable.
If we compare the asphalt fabric with waterproofing sheets, the latter are presented as a more effective and reliable solution, more flexible and adaptable to different crack shapes and with a long-lasting waterproofing, safer installation and less maintenance.
In addition, they not only act as a barrier against leaks but are also suitable for renovation and rehabilitation works as they can be applied over existing surfaces, making them a more efficient and modern alternative and the best waterproofing material available today.
Below is a comparison of the differences between traditional roofing felt and Guru’s Water-Stop waterproofing membrane, where the main characteristics, advantages and applications can be seen.
|
Feature |
Traditional Bitumen Tarpaulin |
Water-Stop Waterproofing Film (Guru) |
|
Base material / reinforcement |
Organic felt, reinforced cardboard, sometimes fiberglass, impregnated with oxidized asphalt. |
Multilayer thermoplastic membrane (EVA, polyolefins), with nonwoven fleece (polyester / polypropylene) on both sides. |
|
Waterproof |
Good at the beginning, but with time it deteriorates (cracks, dryness, stiffness) allowing leaks. |
High from the start, maintains properties for longer against movement and cracking, continuous barrier. |
|
Thickness / weight |
Thicker, heavier; variety of thicknesses but typically bulkier than Water-Stop. |
Very thin (~0.57 mm), light (~270 g/m²) and with a structure that facilitates easy handling |
|
Flexibility / adaptation |
Less flexible; the fabric may tear, dry out, crack with structural movements or temperature changes. |
High flexibility, it allows to adapt to corners, curves, changes of plane… |
|
Installation |
Usually requires heat (hot asphalt or torch), more laborious maneuvering, safety risk, plus support preparation. |
Installed without fire, with type C2 cementitious adhesive; faster installation, less skilled labor, can be placed over existing surfaces in some circumstances. |
|
Durability |
Shorter useful life; deterioration with sun exposure, environmental changes, requires maintenance or replacement after a few years. |
Longer service life under good installation/protection conditions; less maintenance. |
|
Initial cost |
Lower start-up cost; relatively inexpensive materials, known technique. |
Higher material cost (although savings when considering durability and lower maintenance). |
|
Added vertical height / thickness |
It can add considerable thickness if multiple coats, protection, finishing, etc. are required. |
Reduced thickness, ideal for renovation, so as not to raise the level of doors, frames, etc. too high. |
|
Ideal applications |
Flat roofs without much structural movement, areas where the initial cost should be very low, temporary repairs. |
Walkable terraces, swimming pools, showers, wet areas, renovations where the height of the pavement is to be maintained, structures with regulatory requirements, places with risk of cracks or need for adaptation, intensive use. |
|
Environmental impact / recycling |
Low sustainability. Generates asphalt residues and smoke during installation. |
High sustainability; recyclable or reusable materials, fire-free installation, lower environmental impact. |
In addition, if you are interested about it, we recommend this related article about EVAC films.
Although it depends on the needs of each project, the disadvantages of the asphalt fabric and its limitations make professionals, more and more, opt for new options to offer the best waterproofing solutions to their clients. If you are looking for quality waterproofing, long-term efficiency and continuous protection, the waterproofing membrane is positioned as the most reliable and modern option.
Frequently asked questions about roofing membranes, roofing membranes and waterproofing membranes
Which is better, roofing membrane or waterproofing membrane?
The waterproofing membrane offers greater durability, flexibility and resistance to the sun and temperature changes. Its installation is safer because it does not require fire and needs less maintenance. The asphalt fabric can be more economical at the beginning, but its useful life is shorter.
How long does a tarpaulin last?
Under normal conditions, roofing felt has a useful life of 5 to 7 years. With the passage of time, it dries out, cracks and loses its waterproofing capacity, causing leaks.
What are the main disadvantages of roofing felt?
Its main disadvantages are its low durability, degradation due to solar exposure, cracks due to structural movements, slower and more dangerous installation with a blowtorch, and the need for frequent maintenance.
What are the advantages of a waterproofing membrane over roofing membrane?
Modern waterproofing sheets, such as Water-Stop, are lighter, more flexible and durable. They are installed without fire, with cementitious adhesives, and are better adapted to irregular surfaces and structural cracks.
Can a waterproofing membrane be laid over an old asphalt membrane?
Yes, in many cases it is possible to install a waterproofing membrane over an existing asphalt membrane, provided that the surface is clean, stable and properly prepared.
What is the difference between an asphalt sheet and the Water-Stop waterproofing membrane?
The asphalt sheet is composed of modified bitumen and requires heat to install, which makes its application slower and more dangerous. The Water-Stop waterproofing membrane, on the other hand, is installed with cement glue, without fire, is more flexible, lighter and maintains its waterproofing properties for many more years.
How long does an asphalt sheet last versus a Water-Stop waterproofing sheet?
An asphalt sheet has an average service life of 7 to 10 years, depending on solar exposure. In contrast, the Water-Stop waterproofing membrane can maintain its properties for more than 20 years thanks to its multilayer thermoplastic composition and resistance to UV rays.
Can asphalt sheeting be used on walkable terraces?
It can be used, but requires additional layers of protection and regular maintenance to avoid cracking. The Water-Stop waterproofing membrane is more suitable for walkable terraces, as its flexible structure and reduced thickness guarantee a lasting watertightness even under pavement.