How to clean an asphalt shingle roof

Asphalt shingles have several advantages that make them a great option for roofing materials. For example, they can easily be adapted to cover many different angles, shapes and sizes, and the wide range of tile shapes and colours can be used to create a great variety of designs. With asphalt shingles, you can give your roof the look you want and ensure that it’s watertight.

Asphalt shingles may require some minor maintenance to preserve their appearance and effectiveness. If you want to go about this the right way, there are a few key elements to keep in mind.

In this article, our roofing specialists explain how to properly clean an asphalt shingle roof.

What happens if you don’t clean your asphalt shingle roof?

One of the biggest concerns for homeowners who neglect to maintain their asphalt shingle roofs is moss growth. When moss grows and thickens on your roof over time, it can cause the shingles to deteriorate and lift.

This can lead to debris building up in areas that should be protected by the shingles, and it can also result in water accumulation on the roof, since moss can soak up moisture.

The moisture can rot the tiles and structure, reducing the lifespan of your roof. You may end up with roof leaks that allow water to infiltrate and damage the inside of your building, particularly the roof insulation.

Black algae, mould and similar problems are common on poorly maintained asphalt shingle roofs, so regular roof cleaning should be a priority.

How to clean an asphalt shingle roof without damaging it

Use the right cleaning product

Most methods for cleaning asphalt shingle roofs require the use of some type of chemical, particularly for algae stains and other aesthetic issues. It’s very important to avoid using undiluted harsh chemicals, which could shorten the life span of your shingles.

For best results, use a 1:1 solution of chlorine bleach and water in a sprayer. Climb up onto your roof (taking the necessary safety precautions to prevent falls and handle the chemicals properly) and spray your roof as carefully and thoroughly as possible.

After spraying the whole roof with the solution, let it stand for 15 minutes.

Use a hose rather than a pressure washer to rinse the roof

Use a standard garden hose to rinse the roof and wash away the cleaning solution. If there are still problematic spots after rinsing, go back up on the roof with a brush and scrub the shingles one by one.

If you use too much pressure on the shingles, you could cause irreversible damage, so avoid pressure washers and brushes with very stiff bristles.

Prevent moss

If you find that moss is growing too quickly on your roof, you might consider installing copper or zinc sheeting on each side of the roof, just below the ridge.

Particles of the zinc or copper will be released when it rains, changing the environment of the roof and making it much less prone to algae and moss growth.

Other tips, tricks and best practices for maintaining your asphalt shingle roof

In addition to general cleaning, there are other steps you can take to help prevent problems that commonly occur with asphalt shingle roofs.

Trim overhanging tree branches

If there are tree branches touching the roof or blocking its sunlight, trim them back. Generally speaking, more sunlight on a roof means less debris buildup and an environment that is generally less conducive to moss and algae growth.

Remove debris from your gutters

It’s also a good idea to get up on your roof with a leaf blower or soft-bristle broom to remove debris, particularly from your gutters. This promotes proper water drainage (which, after all, is one of the main functions of a roof!) and prevents the formation of moss and algae.

Worried about the state of your roof? Contact les Couvreurs Duro-Toit

If you can’t remember the last time you cleaned your asphalt shingle roof, it might be time to take care of it! If you follow the suggestions in this article, you will eliminate moss and debris that could make your roof deteriorate faster.

If you suspect that the state of your roof requires more than a simple cleaning, ask our specialists to inspect your roof to get a better picture of the situation. That way, you’ll know for sure whether your shingles have reached the end of their lifespan and you need to partially or completely redo your roof to avoid more serious problems.