The garage roof is not just the upper boundary of the building, but a critical element that ensures the safety of the car and tools. In conditions of changeable climate, when showers give way to frosts, it is the roofing carpet that takes the brunt of the elements. Usage roofing felt remains a classic and time-tested solution for flat and pitched roofs of outbuildings. This is a material that has proven its effectiveness for decades when installed correctly.
However, the modern building materials market offers many modifications of bitumen coatings, and it is easy for a beginner to get confused in the abbreviations and markings. The quality of the chosen canvas directly determines how often you will have to climb onto the roof with a blowtorch in your hands. In this article, we will analyze which material is suitable for your case, how to prepare the base, and what nuances of technology cannot be ignored so that the roof lasts at least 10 years.
It is worth understanding that saving on roofing materials often leads to double costs in the future. A leaking roof can ruin not only the interior decoration, but also the car itself, causing corrosion of the body. Therefore, the approach to selection welded material must be balanced and technically competent.
Types of roofing felt and their characteristics
Traditional roofing felt is a cardboard base impregnated with bitumen. However, pure bitumen tends to crack in the cold and leak in the heat. That is why modern technologies have introduced polymer additives, creating a group of materials often called “euroroofing material”. The main difference lies in the base: if earlier it was cardboard, now they use fiberglass, fiberglass and polyester. These materials do not rot and have high tensile strength.
When choosing a coating for your garage, it is important to pay attention to the markings. The letter “K” in the designation indicates a coarse-grained coating that protects against ultraviolet radiation, and “P” indicates a dust-like coating, usually used in the lower layers or for internal waterproofing. For the top layer of a garage roof, it is critical to use a material with a protective coating, otherwise the sun's rays will destroy the bitumen in a couple of seasons.
⚠️ Attention: Do not use roofing felt marked “P” (pulverized coating) as a top coat on an open roof. It is intended only for lining work or temporary waterproofing and will quickly deteriorate when exposed to the sun.
There is also a division according to the type of bitumen modifier. SBS-modified materials (styrene-butadiene-styrene) are more elastic and better tolerate low temperatures, which is important for northern regions. AMS-modified (atactic polypropylene) withstand high temperatures better, but become brittle in severe frost. For a garage in the middle zone, the best choice is often the SBS modification based on fiberglass.
Selection criteria: which roofing felt is best for a garage
The specific type of roofing felt you choose depends on the design of your garage roof. If it is a flat roof with a slight slope, the requirements for tightness and tensile strength increase. In this case, weldable materials based on fiberglass. They are able to withstand deformations of the base without ruptures, which often happens when garage walls shrink or thermal expansion of floor slabs.
For pitched roofs, where the angle of inclination exceeds 15 degrees, you can use lighter options based on fiberglass. However, it is important to consider the method of fastening here: on steep slopes, fusing can be difficult, and sometimes it is necessary to combine methods or use mechanical fasteners in addition to bitumen mastic.
When purchasing rolls, be sure to check the production date. Bituminous materials are not recommended to be stored for more than 18 months, as they may stick together in the roll or lose elasticity even before installation. High quality roofing felt should unwind easily at temperatures above +5°C without cracking at the bends.
When buying a roll of roofing felt, unfold its edge: if cracks are visible on the surface or the topping easily crumbles when slightly bent, the material is old or defective, you should not buy it.
Comparison table of roofing materials
To organize the information and help you make the right decision, here is a comparison of the main characteristics of various types of roofing materials used for garages. It is important to understand the difference between service life and price, since cheap material will require replacement after 3-5 years.
| Material type | Base | Service life (years) | Temperature |
|---|---|---|---|
| Ruberoid (classic) | Cardboard | 5-7 | -20...+50°C |
| Rubemast | Fiberglass | 8-10 | -25...+60°C |
| Linokrom / Bikrost | Fiberglass | 10-12 | -30...+70°C |
| Technoelastic / Uniflex | Polyester | 15-25 | -40...+90°C |
As can be seen from the table, the transition to the basics from fiberglass and polyester significantly increases the durability of the coating. Polyester has the best elasticity, making it ideal for roofs subject to vibration or ground movement. However, for a standard garage cooperative, the optimal price/quality ratio often becomes Linocrom or similar mid-grade materials.
Preparing the base and necessary tools
The quality of laying roofing felt depends 80% on surface preparation. The base must be dry, clean and level. If you are laying roofing felt on concrete slabs, you must seal all cracks and potholes with cement mortar or special repair compounds. The presence of sharp protrusions or stones can damage the integrity of the carpet when heated or during use.
Before starting work, the surface must be thoroughly cleaned of debris, dust and old peeling waterproofing. The ideal option is to use an industrial vacuum cleaner or a powerful broom. After cleaning, the base must be primed bitumen primer. The primer binds residual dust and improves the adhesion (adhesion) of the base material to concrete.
☑️ Preparing the roof for installation
To work you will need a specific set of tools. The main one is a gas burner with a propane cylinder. You also need a hook for rolling out the roll, a spatula for rolling seams and a knife for cutting the material. Do not forget about personal protective equipment: work on the roof should be carried out in thick clothing and shoes with non-slip soles.
⚠️ Attention: It is strictly forbidden to fuse roofing material onto a wet base. When heated, water trapped under the bitumen layer will turn into steam, which will lead to swelling of the roof and the formation of bubbles that will burst at the first frost.
Laying technology: step-by-step instructions
The process of installing roofing felt using the fusing method requires compliance with the temperature regime and sequence of actions. First, the roll is rolled out over the surface for fitting and cut to size, taking into account the overlap. The material is then rolled back towards the center, leaving a small area free to begin work. Heating is carried out evenly, melting both the bottom layer of the roll and the base.
It is important not to overheat the bitumen, otherwise it will lose its properties, but underheating will lead to poor adhesion. An indicator of proper heating is the melting of the protective film with the manufacturer’s logo or the appearance of a glossy sheen of bitumen. After warming up, the roll is slowly rolled out, pressing it to the base and smoothing it from the center to the edges to remove air.
The nuances of working with adjacencies
In places where they adjoin walls or pipes, roofing material is placed onto a vertical surface to a height of at least 15-20 cm. To do this, use additional strips or make an “approach” of the main sheet, heating the corner with a burner especially carefully.
Laying is usually done in two layers. The first layer (lining) is laid with an overlap of 10 cm, the second (finishing) - with an overlap of 15 cm, overlapping the joints of the lower layer. This creates a monolithic, waterproof carpet. After cooling, the seams must be additionally coated with bitumen mastic to ensure tightness.
The main secret of durability is high-quality heating of the seams. It is the joints that are the weak link of any soft roof, so they need to be given maximum attention during installation.
Typical errors and coating service life
The most common cause of leaks is poor preparation of the base or violation of fusion technology. Mistakes, such as laying on a wet surface, insufficient heating of the seams or skimping on the number of layers, nullify all efforts. They also often forget about parapet covers or protection of vertical sections where water constantly flows.
The service life of a roofing felt roof directly depends on the quality of the material and climatic conditions. Classic cardboard-based roofing felt lasts about 5 years, after which it requires major repairs. Modern materials based on fiberglass with polymer additives (TechnoNIKOL, Linokrom) are capable of serving for 10-15 years or more without the need for intervention.
- 🏗️ Using cheap cardboard-based materials for major repairs.
- 🌧️ Ignoring the roof slope and organizing stagnant water zones.
- 🔥 Overheating of bitumen, leading to loss of elasticity and cracking.
- 🧹 Lack of regular cleaning of the roof from leaves and debris, which causes rotting and moisture retention.
Regular inspection of the garage roof at least twice a year (in spring and autumn) will allow you to timely identify minor defects and eliminate them with local repairs, without leading to a large-scale leak.
Frequently asked questions (FAQ)
Is it possible to glue roofing felt to cold mastic without a torch?
Yes, such a method exists, especially for materials with a self-adhesive layer or when using special bitumen mastics. However, the reliability of the adhesive connection in vertical and complex areas is often inferior to the fusion method. For a garage where maximum tightness is important, fusing is preferable.
How many layers of roofing felt should be laid on a flat roof?
According to building codes, it is recommended to lay at least two layers on flat roofs. The first layer performs the function of leveling and additional waterproofing, the second is the main protective one. At junctions and funnels, the number of layers is often increased to three or four.
At what temperature can roofing felt be laid?
The optimal temperature for working with deposited materials is from +5°C to +25°C. At lower temperatures, bitumen becomes brittle and does not heat up well, and at too high temperatures (+30°C and above) there is a risk of overheating and deformation of the material during installation.
What is the difference between Bikrost and Technoelast?
The main difference is in the material class and base. Bikrost is an economy-class material, often based on fiberglass, with a shorter service life. Technoelastic is a premium polyester-based material with a high content of polymer additives, providing high elasticity and a service life of up to 25 years.