How to clean a roof?

How to clean your roof like a pro after winter?


Just as you clean your car at regular intervals to remove dirt, debris, and the like, cleaning your roof is important not only to ensure it is always in good condition but also to restore its luster. But what does it take to clean your roof? When should it be cleaned? With what? By whom? We tell you everything!

When to clean your roof?

It is recommended to clean your roof at least twice a year, namely in spring and autumn.

Why is that? Because you can also take the opportunity to inspect it before the cold weather arrives, to make sure there are no cracks or tears that could lead to water infiltration.

And during spring cleaning, you can also carry out another inspection, this time to ensure that the weight of snow and ice has not caused any damage to your roof.

For the best conditions, make sure you clean your roof on a dry, cool and windless day. It is no secret that standing on your roof in windy conditions can be very dangerous, even on a flat roof!

Steps to follow for a good roof cleaning

A thorough and proper roof cleaning involves more than just removing leaves and debris; there are several steps that must be followed to complete the task:

  • Cleaning with a Kärcher,
  • Application of moss deterrent or fungicide,
  • Water-repellent treatment,
  • Painting to re-waterproof (if necessary).

Cleaning with a kärcher

Cleaning with a Kärcher, or if you prefer, a pressure washer removes dirt, debris and moss (if any) quickly and efficiently. But when you say pressure washer, you say… pressure, and hence possible damage.

Indeed, the force of the spray could damage the roof, especially if you are cleaning tiles. It is best to ensure that the jet is of adequate strength before you start!

If you have a flat, TPO or EPDM roof, be sure to refer to the manufacturer’s recommendations before using a pressure washer, as it could damage your membrane.

Application of a moss deterrent and fungicide

Once the roof has been cleaned, a moss killer product should be applied to gradually eliminate the remaining moss on your roof and prevent it from reappearing. A fungicidal treatment will prevent the proliferation of fungus and algae.

If you have a flat roof, choose a suitable moss deterrent product that will not damage the type of material used (membrane, asphalt, etc.).

Water-repellent treatment

This treatment will reduce the porosity of the roof and increase its waterproofing. Again, make sure you use the right product for the type of material covering your roof!

Re-waterproofing the roof

You may need to waterproof your roof again to fix or prevent minor leaks. There are various products and paints on the market to deal with this.

Man eliminating stagnant water on flat roof

What about elastomeric or asphalt and gravel roofs?

To clean an elastomer roof, start by using a leaf blower followed by a good sweep. Then, seal any joints damaged by winter weather with a sealant and add granules on spot where the membrane is lacking any. This will get you through the next year with confidence!

For asphalt and gravel roofing, also remove debris, check joints on the flashing and check the bituminous flashings around the perimeter. Then, where the paper is burned, split or cracked, repair with plastic cement and cotton. Caution: Using water, brooms or leaf blowers is not recommended as with other types of roofing.

What products should i use to properly clean my roof?

To carry out a thorough cleaning of your roof, you need to use cleaning products designed for this purpose and able to dislodge the dirt and mold embedded in your roof.

Afterwards, the application of a moss-deterrent product and a waterproofing product will protect your roof from the weather and prevent the onset of problems.

Call in an expert or do it yourself?

It is possible to clean your roof yourself, provided you have the right tools and know how to proceed (and of course, follow the safety rules).

If in doubt or if you don’t have the right equipment, it is best to call in roofing specialists. Not only do they have all the necessary equipment, but they will know which techniques and products to use, depending on the type of roof and its coating.

In summary

In order to preserve your roof and ensure that its lifespan is optimal, it is important to take good care of it. The following points will give you the best chance of success:

  • Cleaning twice a year, in spring and autumn, ideally with a pressure washer,
  • Inspection to ensure that no breaks or tears have occurred,
  • Application of a moss deterrent,
  • Application of waterproofing (if required),
  • In the case of an asphalt and gravel roof, do not use water or a broom.

And if your roof is past the spring-cleaning stage, our specialists can help you with maintenance and repair work. Don’t hesitate to contact us!

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