Do-it-yourself garage roof repair using roofing felt: step-by-step instructions with photos and tips

Why is roofing felt the best choice for a garage roof?

The garage roof is the first barrier that protects your car from precipitation, temperature changes and mechanical damage. Over time, even the most durable roof begins to leak, crack, or peel off. Ruberoid remains one of the most popular materials for repairing garage roofs due to its availability, ease of installation and reliability. Unlike metal sheets or tiles, it does not require special tools and is suitable for roofs with any slope - from flat to pitched.

But why exactly roofing felt and not modern membranes or bitumen mastics? Firstly, this optimal price-quality ratio: a roll of material 1 meter wide and 10 meters long will cost 300–800 rubles, depending on the brand and density. Secondly, You can do roofing felt repairs yourself in one day, without resorting to the help of professionals. Finally, this material is rot-resistant, UV-resistant (if you choose a top layer with stone topping) and lasts up to 15 years if installed correctly.

However, not everything is so simple: errors during installation can negate all the benefits. For example, laying roofing felt on a damp base reduces its service life by 2–3 times, and improper overlap of joints leads to leaks after the first rain. In this article we will analyze the step-by-step technology for repairing a garage roof with roofing felt, select suitable materials and reveal the secrets of the durability of the coating.

What materials and tools will be needed?

Before you begin the repair, prepare everything you need. Not only the appearance of the roof, but also its tightness depends on the quality of materials. Here's the basic set:

• 📜 Ruberoid (brands RKP-350, RKK-420 or Euroroofing material) - for the lower and upper layers. Optimal density: 300–400 g/m².
• 🔥 Bitumen mastic (cold or hot) - for gluing roofing felt to the base. Alternative: gas burner for built-up roofing felt.
• 🛠️ Tools: knife for cutting roofing felt, roller or brush for mastic, spatula, hair dryer (if necessary).
• 🧴 Primer (primer) - for treating a concrete or wooden base before laying.
• 🧲 Metal strips and nails — for fastening the edges of roofing felt on pitched roofs.
• 🩹 Sealant (silicone or bitumen) - for sealing joints and cracks.

When choosing roofing felt, pay attention to its marking:

• 🔹 RCP - roofing felt with dusty topping (suitable for lower layers).
• 🔹 RKK — with coarse-grained topping (used for the top layer).
• 🔹 Euroroofing material - a modern analogue with polymer additives, more elastic and durable.

It is optimal to use for a garage roof two-layer installation: first layer - RKP-350, second - RKK-420 or Euroroofing material. This will ensure maximum waterproofing. If the roof has a slope of more than 15°, you can limit yourself to one layer RKK-420 with fusing.

Preparing the roof for repair: cleaning and leveling

80% of the success of the repair depends on the quality of foundation preparation. If you lay roofing felt on a dirty, uneven or wet surface, it will quickly peel off. Start with complete roof cleaning:

1. Remove debris, leaves and old pieces of roofing felt using a stiff brush or scraper.
2. Rinse the surface with water from a hose (if the roof is concrete) or vacuum it (if it is wooden).
3. Pay special attention joints and cracks - they need to be expanded with a spatula and cleaned of dust.

Next level the base:

• 🪨 On a concrete roof: seal the cracks with cement mortar (1 part cement to 3 parts sand) or a special repair mixture.
• 🪵 On a wooden roof: replace rotten boards, level the surface with plywood or OSB boards.
• 💧 If the roof is wet, dry it with a construction hairdryer or wait for sunny weather (the humidity of the base should be no more than 4%).

After leveling, apply primer (primer) - it will improve the adhesion of the roofing material to the base. For concrete, use a bitumen primer; for wood, use an antiseptic primer. Apply with a brush or roller in 1-2 layers, allowing each layer to dry for 2-3 hours.

⚠️ Attention: If there are traces of mold or mildew on the roof, treat it chlorine solution (for example, “White”) or a special antiseptic. Otherwise, the roofing material will begin to rot from the inside!

Roofing felt laying technology: step-by-step instructions

Now we move on to the most important stage - laying roofing felt. There are two main methods: for mastic (cold method) and fusing (using a torch). We will consider both options.

Method 1: Laying on bitumen mastic (for beginners)

This method is simpler and safer, as it does not require working with open flame. Suitable for small garages with a flat or slightly pitched roof.

1. Application of mastic: Using a brush or roller, cover the base of the roof with bitumen mastic (consumption: ~1 kg per 1 m²). The layer should be uniform, without gaps.
2. Laying the first layer: Roll out a roll of roofing felt RKP-350 along the roof, starting from the lowest point (if the roof is pitched). Overlap between stripes - 10–15 cm. Press the roofing felt with a roller, squeezing out any air bubbles.
3. Sealing joints: Coat the overlaps with mastic and additionally glue them with strips of roofing felt 10 cm wide.
4. Second layer: After the first layer has dried (after 4–6 hours), repeat the process with roofing felt RKK-420, shifting the joints relative to the bottom layer by 30–50 cm.

Method 2: Fusing roofing material (for experienced ones)

This method is more complicated, but provides better waterproofing. You will need a gas burner and built-up roofing material (for example, TechnoNIKOL or Bipole).

1. Warming up the base: Heat the roof section with a burner to a temperature of 150–180°C (the bitumen on the roofing felt should begin to melt).
2. Deposition: Roll out the roll, simultaneously heating its underside and base. Move towards yourself to avoid bubbles forming.
3. Rolling: Roll the laid roofing material with a heavy roller for a tight fit.
4. Joints: Fuse the next sheet with an overlap of 8–10 cm, heating both layers.

For pitched roofs (slope >15°), additionally secure the edges of the roofing material metal strips in increments of 50 cm, nailing them with nails or self-tapping screws.

Parameter	Mastic method	Fusing method
Difficulty	Low	High
Service life	8–10 years	12–15 years
Cost	Low (mastic + roofing felt)	Medium (burner + built-up roofing felt)
Installation time	4–6 hours	2–3 hours
Suitable for slope	Up to 10°	Up to 30°

⚠️ Attention: When fusing roofing material do not overheat the bitumen - it can catch fire! Optimal burner flame temperature: 500–600°C. Keep a fire extinguisher or bucket of sand handy.

Common mistakes and how to avoid them

Even experienced craftsmen sometimes make mistakes when repairing a roof with roofing felt. Here are the most common ones and ways to prevent them:

• 🌧️ Laying on a damp base → Ruberoid will peel off after 1-2 seasons. Solution: Use a moisture meter or check the dryness of the base using the “folk method”: place a piece of polyethylene on the roof overnight. If there is condensation on it in the morning, dry it further.
• 🔥 Insufficient heating during fusion → Poor adhesion, bubbles. Solution: Warm up the base until light smoke appears from the bitumen.
• 📏 Small overlap of joints → Leaks at the seams. Solution: The minimum overlap is 10 cm for mastic and 8 cm for fusing.
• 🌀 Uneven base → Ruberoid breaks in places where there are differences. Solution: Level the roof with cement or plywood.
• ☀️ Working in hot weather (>30°C) → The mastic dries too quickly, resulting in unglued areas. Solution: Work in the morning or evening.

Another common problem is bubble formation after installation. They appear due to air remaining under the roofing felt. To avoid this:

• Roller rolling should go from the center to the edges.
• When melting, move the torch undulating, and not in a straight line.
• If bubbles have already appeared, puncture them, squeeze out the air and seal with mastic.

What to do if the roofing material begins to peel off after a year?

If the roofing material has moved away from the base, but the material itself is intact, you can try “resuscitation”:

1. Lift up the peeling edge and dry the base with a hair dryer.

2. Apply fresh mastic or melt the bitumen with a torch.

3. Press the roofing material with a roller and place a load on it (for example, sandbags) for 12 hours.

If the material crumbles, you will have to replace the entire sheet.

Roof care after repair: how to extend its service life

Even perfectly laid roofing felt requires maintenance. Here are some tips to help your roof last longer:

• 🧹 Cleaning: Remove leaves, snow and debris from the roof twice a year (spring and fall). Use a soft brush to avoid damaging the topping.
• 🔧 Inspection: Check your roof after heavy rain or hail. Pay attention to the joints and edges - this is where leaks most often begin.
• 🎨 Coverage update: Every 3–4 years, apply a layer of roofing material bitumen emulsion or liquid rubber - this will restore waterproofing.
• ❄️ Winter protection: Don't knock ice off the roof with a crowbar! Use anti-icing systems or sprinkle sand over the ice.

If small cracks appear on the roofing felt, they can be fix it yourself:

1. Clean the crack from dirt and dry it.
2. Fill it up hot bitumen mastic or roof sealant.
3. Glue a 10x10 cm roofing felt patch on top.

To extend the life of the roof you can use protective coatings:

• 🛡️ Acrylic paint for roofing felt — protects from UV rays and gives an aesthetic appearance.
• 💎 Liquid rubber — creates an additional waterproofing layer.
• 🧱 Stone chips — increases resistance to mechanical damage.

Repair cost: comparison with other materials

One of the main advantages of roofing felt is its availability. Let's compare the cost of repairing a garage roof (area 20 m²) using different materials:

Material	Cost (per m²)	Service life	Difficulty of installation
Ruberoid (2 layers)	150–300 ₽	10–15 years	Low
Bituminous shingles	400–800 ₽	20–25 years	Average
Corrugated sheet	350–600 ₽	15–20 years	High (requires welding)
PVC membrane	500–1200 ₽	25–30 years	High (experience required)
Liquid rubber	600–1000 ₽	10–15 years	Medium (needs equipment)

As can be seen from the table, roofing felt is the most budget option, but it loses in durability. However, if we consider that You can do roofing felt repairs yourself, without involving a team, the final savings will be 50–70% compared to other materials.

Cost of materials for a 20 m² roof:

• 📜 Ruberoid RKP-350 (2 rolls of 10 m each) - 1200–1800 ₽.
• 📜 Ruberoid RKK-420 (2 rolls) - 1600–2400 ₽.
• 🧴 Bitumen mastic (20 kg) - 800–1200 ₽.
• 🧴 Primer (5 l) — 300–500 ₽.
• 🛠️ Tools (if out of stock) - 1500–3000 ₽.

Total: repairing a garage roof with roofing felt will cost 5000–9000 rubles (excluding tools). For comparison, calling a crew to lay corrugated board will cost 15,000–25,000 rubles.

FAQ: Answers to frequently asked questions

Is it possible to put roofing felt on old roofing felt?

Yes, but only if the coating is old didn't swell and didn't crumble. Before laying a new layer:

1. Clean the roof of debris and loose pieces.
2. Prime the old roofing material with bitumen primer.
3. Lay a new layer perpendicular old one so that the joints do not match.

If the old coating is in poor condition, it is better to remove it.

Which roofing material is better: domestic or imported?

Domestic roofing felt (for example, TechnoNIKOL or Aquaizol) is not inferior to imported ones in quality, but costs less. Imported analogues (for example, ICOPAL or SOPREMA) differ:

• Higher elasticity (does not crack in the cold).
• Improved UV protection.
• Long service life (up to 20 years).

For a garage, a domestic brand of roofing felt is sufficient. RKK-420 or Euroroofing material.

What to do if the roof leaks after repair?

Causes of leaks and solutions:

• 💧 Poorly taped joints → Heat the seams with a torch and roll them with a roller.
• 🕳️ Cracks in roofing felt → Fill with bitumen mastic and apply a patch.
• 🏗️ Damage to the base → Disassemble the covering, repair the roof and lay the roofing material again.

If the leak is severe, check internal drainage - the drains may be clogged.

Is it possible to paint roofing felt?

Yes, but only acrylic paint for bitumen surfaces (for example, Tikkurila Kiva or Dali). Paint:

• Protects against UV rays.
• Extends service life by 2–3 years.
• Gives the roof a neat appearance.

Before painting, clean the roofing material from dust and prime it.

How long does it take for roofing felt to dry after installation?

Drying time depends on the installation method:

• 🧴 On mastic: 12–24 hours (full setting - 3 days).
• 🔥 Fusing: Cools down in 1–2 hours, complete polymerization takes 1 day.

In rainy weather, drying time increases by 1.5–2 times.