Renew Garage Roof And Completely Renovate – Instructions

Renew Garage Roof And Completely Renovate – Instructions

A garage roof must be renovated at regular intervals so that it retains its impermeability. If the damage is too severe or if you want to make a change, then a complete renewal is necessary. In this guide, we will present you with various options for bringing the garage roof back into shape.

Various materials are possible for the garage roof. It is often a flat roof that needs to be protected against the weather. Water ingress would cause permanent damage to the roof, so adequate protection must be provided here. After completion of the renovation or renewal, you can apply either gravel or greenery. This increases the protective effect. Special mats are offered for greening , which you can plant. Gravel can often also be required for weighting and thus fulfills a wide range of tasks.

The renovation of the roof

When renovating, it is important to fix all the damaged areas. Leaks allow moisture to enter and thus spread the damage. At the latest when the water penetrates through the roof, a garage roof renovation is necessary. In order to limit the extent of the damage, you should carry out regular inspections of the roof and rectify danger spots immediately. The special thing about the renovation is that you can often keep the old covering and repair individual areas. This reduces costs and effort.

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Replacing the garage roof

If you renew the garage roof, you have the choice of whether you want to keep the old covering or decide on a new variant. When renovating, you get the opportunity to improve the weather protection and to optimize the climate through greening. During renewal, the old covering is removed and a new covering is applied.

Liquid plastics are suitable for making the roof watertight when refurbishing for permanent protection against the ingress of water . Rain, snow and hail can cause moisture to penetrate and cause severe damage. Suitable sealants combine with the substrate during renovation and thus prevent water from penetrating. It is best to combine a fleece with a layer of liquid plastics, this will give you the best effect. In any case, make sure you choose the right products, as not all products are suitable for every surface. The cost of liquid plastics is around 15 euros per liter. With this amount you can repair about 5 to 8 square meters.

Tip: AXOL is a versatile product that is suitable for concrete, wood, metal or fiber cement, for example. Apply the fleece and apply the liquid plastic with a brush or roller.

Before applying the new covering, you must thoroughly clean the surface. After you have removed the rough remains of the old covering, you can work with the high-pressure cleaner. Use a suitable nozzle and pay attention to the appropriate distance. In general, a minimum distance of at least 60 to 80 centimeters is recommended to avoid damaging the roof.

Lay bitumen sheets

Bitumen membranes can be used both for renovation and for complete renewal. For work you will need the following materials:

  • gas burner
  • bitumen membranes
  • Messer

Proceed as follows when laying the bitumen sheets:

1st step: Position the first bitumen sheets on the roof.

2nd step: Heat the underside of the bitumen membrane with the gas burner.

3rd step: Lay the second panel as close as possible to the first panel. The overlap should not be more than 20 centimeters.

4th step: Heat up the abutting edges so that they can be connected with a welding track.

5th step: Proceed according to the first steps over the entire roof area and cover the roof with the bitumen sheets.

Step 6: Apply a second layer of bitumen sheeting. Lay individual strips perpendicular to the first row so that there is an offset of 90 degrees. This increases the tightness of the layers and improves stability.

Tips for laying the bitumen sheets:

  • Begin the work from the lowest point of the roof.
  • Only roll out larger lengths of around 2 meters and then start heating the underside or the base.
  • Ensure sufficient heating so that the material bonds well to the substrate.
  • Two lanes should not overlap by more than 20 centimeters.


On average, you have to reckon with material costs of around 5 to 10 euros per square meter.

advantages and disadvantages

Roofing felt is characterized above all by its low price and ease of processing. The high maintenance requirements and the tendency to cracks or softening of the material are disadvantageous. Under the influence of great heat, waves can form in individual lanes. However, regular inspection and renovation measures will give you good protection for the roof. This is protected from moisture from rain.

Attention: Should waves form, then there is no longer any protection from the rain at these points.

Roofing felt

For the covering with roofing felt you need the following materials:

  • Bitumen
  • Roofing felt
  • roofing nails
  • broom
  • pneumatic nailer

Step 1: Sweep the roof thoroughly with the broom. It must be free of dirt particles and gravel and greenery must also be removed.

2nd step: If you recognize any damage after cleaning, then repair them with a bitumen coat. Bubbles have often formed, which have also become or will become problems. They are caused by exposure to high temperatures. Prick or cut open the blisters and use cold tar to bind the material to the ground.

3rd step: Now lay out the first panel. This must not be too flush with the existing tar paper. A displacement of around 10 centimeters is ideal.

4th step: To apply the roofing felt, place it in the desired position and fix it with the help of roofing felt nails.

Step 5: Once you have applied the first piece, step on the roofing felt with one foot.

Tip: In any case, make sure you have a secure footing and the load-bearing capacity of the roof.

Step 6: Lay the tar paper piece by piece.

Tip: Make sure there is an overlap of around 10 centimeters to ensure a tight shape.

7th step: Once the laying is complete, there are usually overhangs on the sides. You now have to glue these with bitumen.

Cost of the roofing felt

You can get roofing felt for around 10 euros per square meter. There are also costs for the nails. These are usually offered in sets, with 100 pieces being available for around 5 euros.

With the help of the roofing felt nail you can attach the roofing felt to the wooden formwork. They are also used to fix slabs of slate. The easiest way is to attach the nails with a pneumatic nail gun. Individual nails are combined with a wire to form the so-called nail belt. The nails are relatively short designs. They are around 20 to 35 millimeters long and have a broad head. This is necessary so that the roofing felt is not torn out by wind and weather influences. To protect against rain, the roofing felt nails are often copper-plated or hot-dip galvanized.

Difference roofing felt and bitumen

Roofing felt is also known as tar paper. It is cardboard soaked in bitumen. It serves as a moisture barrier during roof construction. Fine gravel, slivers of slate or coarse-grained sand can be incorporated to improve the function. This improves UV resistance and abrasion resistance. Roofing felt can be used under roof tiles to form a second layer of covering. However, it can also be used as the only protective layer on garage roofs, gazebos and similar buildings. This makes it more susceptible to weather influences. A bitumen membrane is thicker than roofing felt and is welded. Roofing felt is placed loosely and nailed.

The peculiarities of the material and environmental protection

In the early 1970s, the tar paper was soaked in coal tar. This contains many toxic substances such as polycyclic aromatic hydrocarbons. The materials include anthracene, benzopyrene and naphthalene. As the environment was polluted by its use, this manufacturing process has now been banned. However, existing roofs often contain roofing felt soaked in coal tar, which must therefore be disposed of properly. This is hazardous waste which, depending on local regulations, must be disposed of directly at the landfill. Modern versions are made with the help of bitumen. Tar is no longer used, although the name has been preserved.

Garage roof renovation – do it yourself or hire a specialist?

If a specialist company is commissioned, the costs for the working hours and possibly the travel costs are added to the prices mentioned. The exact cost depends on the company. On average, you have to reckon with expenses of 50 to 100 euros per working hour and person. Smaller renovations can usually be carried out by yourself without any problems, for larger work you can call in a specialist for support if necessary.