Garage roof leaks: 10 tips for what to do

9 min

When the roof of the garage is leaking, especially during the rainy or snowy season, you need to urgently fix the problem. Otherwise, with a high probability, all the property inside the premises will either be partially damaged or become completely unusable. Below we present important points and interesting, effective and practical solutions to this issue.

The main causes of the problem

  1. Insufficient slope angle. In this case, you can make an additional superstructure-frame made of wood and lay a new coating on it.

  2. Depressurization or poor sealing of joints. Here, only the analysis of the place with the problem, drying and laying of new material with new gluing of the seams.

  3. A small number of soft roof layers for a specific object. If the coating is recently laid, then you can simply try to supplement the missing layer. If the roof has already been used for several seasons, then most likely everything will have to be redone from scratch.

  4. Base defects. A soft frame under the roof or its breakage cause subsidence and breakage of the coating. In this case, you can try to either strengthen the base or redo it completely.

  5. Insufficient roll-type overlap. Alternatively, make a new coating layer on top. In most cases, you just need to do it again, but taking into account the technology.

  6. Physical defects in materials. This problem is solved by replacing part of the roof or the entire coating.

Roof types

To find the right approach, you first need to decide on the features of the roof structure and the type of roof. Then it will be relatively easy to choose a method of treatment. So:

If the roof of the garage and the house is piecework

Here, problems often arise at the place of joints and transitions. Less commonly, the cause is a mechanical defect (crack, hole). Damage from hail, wind, etc. may also occur. It is also important to evaluate the quality of the liquid flow from the surface. If in some places a lot of snow and leaves constantly accumulate, then this is one of the most vulnerable areas of coverage in general. The same nuances apply to designs with additional elements: a cuckoo, etc.

If the roof is pitched

  • Most often, in such structures, problems arise due to the absence of even a minimum angle of inclination of the roof. Puddles form after precipitation, water begins to seep into the room with poor joints, loose adhesion of roof sheets.
  • In some cases, the leak begins after a strong wind, when part of the coating is ripped off or undermined.
  • Another option is poor coating quality and frequent mechanical stress. For example, when a seasonal terrace is equipped on the roof, but during construction this moment was not thought out. Consequently, the strength of the roof is not designed for additional permanent loads and problems arise.

If the roof is gable

In such a system, problems with physical defects will be more frequent. Something broke, cracked, broke through with a branch, stone, hail, etc. Another option: failure due to a long service life, factory defect, improper installation. The joints are also considered weak: corners, turns, gutters, etc.

Further, different roofing options will be considered.

Council number 1. What to do with slate?

If the roof is covered with slate, then there are two variants of the problem:

  • Damaged slate sheets. To eliminate such a defect, you need to remove those parts that have cracks, holes, etc. After that, replace them with new, whole ones. If the leak was long and many sheets, albeit intact, but managed to get wet, damp, you need to remove all the “damaged” parts, dry well and then put back.

Important! If mold has formed on the sheets or a lot of dirt has accumulated, they must be rinsed before drying and installation.

In some cases, the sheets are repaired by old-fashioned methods: they glue the cracks with textile strips soaked in oil paint, work them with linseed oil or other moisture-protective substance. After that, the sheet is set back. To strengthen the protective properties, you can also paint the sheets on top.

  • Failure of waterproofing. After a gap is found, you need to act taking into account the coverage itself. The bottom line is this – find the reason. Eliminate dirt, mold, rotted elements and restore the integrity of the coating by patching a hole or joint and performing moisture insulation, one might say, sealing all seams.

Council number 2. What to do with shingles?

If the leak is small, you just need to replace the part with which you have problems. For this:

  • We take a nailer and remove all damaged shingles. The device must be handled carefully so as not to damage the whole elements.
  • Checking the lining. If there are signs of leaks in it, obvious delamination or divergence of the seams, then we apply bitumen-polymer mastic to these places.
  • We attach a new element that matches the color and shape.
  • We carefully process the joints.

In extreme cases, the roof is completely changed. Usually drastic measures are needed when working with very old or poor quality coatings. If a leak was found in this case, then the replacement of individual sections may be too dreary and time-consuming. Therefore, be careful about assessing the scale of work and the practicality of the chosen option for resolving the issue.

Council number 3. We quickly fix a soft roof

One of the options that is often found, but on old buildings. Many modern types of roofing show themselves to be more practical. Nevertheless, let’s figure out what to do if there are problems with such a roof. Need to:

  • Remove the damaged area.
  • Remove all moisture, dirt, mold.
  • Dry well.
  • Coat the seams and joints of the base of the slabs or other base with mastic or other moisture insulating substances.
  • Install additional means of preventing leaks (primers, etc.).
  • Lay out a new roof layer taking into account the technology. The overlap should be at least 15-20 cm.

Below is a video showing a practical way to fix a soft roof.

Look for alternatives to roofing felt if possible. Today there are many analogues of this roofing material in hardware stores. Be sure to ask a consultant to talk about the characteristics, advantages and disadvantages. The easiest way to try is to search the local shops if you want to “see and feel” what it is. Sometimes they offer different improved versions of roofing material, fiberglass, etc.

Important! It is also important to use bitumen, mastic and other substances that are used for gluing joints correctly. There is no need to rush or try to pour / smear more – this can form air bubbles. You need to follow the instructions for using a specific material or consult a master

Quick solution to basic problems:

  • Bloating. We cut the place with an envelope, dry it, clean it, fill it with mastic, make a patch on top, which we also waterproof.

  • Cracks. Often formed due to too much tension and the use of a material that does not tolerate temperature changes or too high temperatures. To repair, we cover up all the cracks and put a layer of roofing material on top, which has the best characteristics.

  • Waves and creeps. Formed due to improper installation. To remedy the situation, you can put a layer of material on top, which must be fixed correctly. For this, additional fixing rails, etc. are used.

  • Loose fit. It is most often found at the joints with chimneys, gutters, etc. Formed due to the fact that fillets were not made in advance. To fix it, we remove the top layer of the coating, on a new layer we cut out the necessary areas in advance and put it according to technology.

Council number 4. Who knows what to do with shingles?

Follow the algorithm:

  • We find the problem area.
  • We remove part of the coating. It is important to take into account that ordinary tiles are laid according to a certain principle – so be careful.
  • We check the integrity of the insulation. We dry the site, update the waterproofing layer if necessary.
  • We put back the old tile or new, taking into account the color and other factors.

Garage roofs are usually not tiled. If the roof is old and you don’t want to risk it, then it is better to immediately contact someone who has experience in this matter.

Council number 5. We quickly fix metal roofs

Frequently used materials for a garage roof are corrugated board and metal tiles. Easy to install, neat in appearance, durable – they have found many fans among construction companies and individuals.

If something went wrong with such a roof, then:

  • If the damage is small, we use one of the options: small tow, rubber paint, waterproofing with any other substance that suits. In some cases, it is proposed to close the leak with roofing material from above, but this option will not be aesthetic.
  • If the leak is serious, and the sheets seem to be intact, then we remove the coating in the intended place and look for problems with the waterproofing layer and fix them.

If we talk about seam roofing, then the quality of rolling seams most often suffers. Either there was a defect in the sheet itself and it was not possible to connect it well with the neighboring one, or simply “they did not put the squeeze on it.” Most often, you need to go through the old sheets again with a special tool. If this does not help, then it may be worth changing a couple of sheets that do not fulfill their function.

Council number 6. If the problem is at the bottom

Holes often appear in concrete ceiling slabs or other ceilings. In this case, you first need to seal them in any suitable way and be sure to waterproof them.

Only patches made of hard, durable materials are suitable. Because when using soft coatings, it is possible to get sagging over time and, as a result, a new leak.

One of the options for solving the issue is presented in the video:

Council number 7. What to do if you still haven’t found the reason

There are three obvious options:

First. We leave everything as it is, wait for the problem to get worse and again look for a place that needs to be fixed. A passive approach that takes time, but sooner or later yields results. It will not work if:

  • The leak is already big.
  • There are many valuable things in the room that will deteriorate in high humidity.
  • The garage is rarely visited.
  • There is no way to escape at any moment and examine the object again.

Second. Radical. Replacement of the entire roof. With a competent approach and correct installation, a new coating, regardless of the type, will last a long time without problems.

Third. Call the master. This option will require additional expenses, but in 99% of cases it will give a good result. Moreover, only this way of resolving the issue can save personal time.

Council number 8. The reason was eliminated, but the roof still leaks

This means that the reason has not been eliminated, or it was not alone. In such a situation, we double-check the place of repair. If everything seems to be done well, then we look for other places with defects, etc. If the cause of the roof leak has not been found, then it is worth reviewing advice number 6 and choosing the appropriate option.

Council number 9. How to check the work of the wizard

At the very beginning, just visually. If, upon a cursory examination, no gnarled joints are visible, the seams are well joined and missed, then, in theory, everything was done normally. It will be possible to check the quality of work after the rainy or snowy season.

As a last resort, you can do something like an experiment: just water the roof with a hose for a while, but this is expensive, impractical and will definitely look strange.

So that there is no doubt about the quality of the wizard’s work, you should look for it according to reviews or recommendations of friends. If this is not possible, then rankings on different search resources can also help.

Council number 10. How often should the roof be inspected?

Many roofing materials function without problems for 10 years. But inspect for clogged drain, deposits of dirt and leaves, cracks, swellings, etc. worth once a year. Preferably after winter. Firstly, in warm weather it will be easier to fix the breakage. Secondly, at this time, it is easiest to notice a leak if there were heavy snowfalls, rains, etc.


It is important to take into account many nuances at the design and construction stage, then there will be fewer questions when using the building:

  • Installation according to technology is the key to the absence of leaks.
  • A proper building layout can prevent many roof problems.
  • Timely inspection of the roof will help to avoid “accidental” disasters after rain.
  • It is very important to make high quality waterproofing.
  • When choosing a roof covering, you need to proceed not only from the budget, but also take into account the features of the terrain, weather throughout the year, etc.
  • If it is not possible to study the issue well, then it is better to contact a specialist.

We wish you to equip your garage so that you do not need the advice in our article!

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Passionate about DIY for over 10 years and all the new tools, I give you through this blog all my advice, tips, tests in all areas: carpentry, electricity, masonry, gardening, home automation ...


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