Tips for roof cleaning

Many people don’t consider the work that goes into maintaining a roof until there is a problem. It doesn’t hurt to periodically inspect your roof to see if there is anything that needs to be done or if it is holding up under the weather and elements. Having someone look at it can help keep costs down as problems will be detected before they become big issues that will require a lot of money and time to properly fix.

How to clean a roof

Your roof type will determine the best method to clean it. Know what material your roof is made of before you get on it for cleaning. Here are the most common ways to remove built-up algae from your roof:

• Pressure washing the roof. This will work best when you are dealing with a metal or tiled roof.
• Chemical washing is best for any type of roof. Make sure it is safe to use with your roof and that it will be effective for your problem.

How to pressure wash it

First, acquire a pressure washer. Consider all the options you have, whether it is to rent or purchase a pressure washer. Once you have the pressure washer, do the following:

• Start at the peak. This way you will work down and shoot the dirty water off the roof and avoid getting it under the shingles.
• Do a small area first. Use medium pressure and keep the head about 30cm from the roof. Lower the wand to the roof until you are able to remove the mould and algae. Make sure to not use too much pressure and damage roofing materials.
• Stand on a dry area while pressure washing. Only stand on areas already clean once you have started as algae becomes very slippery when it is wet.

Using chemicals

The best option to use when doing chemical cleaning is chlorine. You can also use a weak solution of sodium hydroxide, however this is the more dangerous of the two options. Protect yourself from chemical burns by donning eye and hand protection.

Be safe

• Have a spotter. If the roof has a steep pitch make sure that you have someone near to watch and get help if necessary.
• Make sure the chemicals you use will not harm you or the plant life below as you spray it off the roof.
• Make sure to use minimal pressure with the pressure washer. It will help you control it and will reduce any harm you may do to your roof.

Removing moss 

In addition to adding a rustic and charming look to your roof, moss may actually be damaging your roof. You’ll want to have any visible moss removed as quickly as possible to reduce your chance of roof damage. 

Why should you remove moss?

The damage caused by roof moss actually comes from rain water runoff. Large sections of moss can impede the flow of water from your roof. These sections of moss act like a dam and cause the water to back up under the shingles on your roof. Additionally, These pools of water take longer to dry and reduce the life of your roof. Over time, large patches of moss can cause roof damage and leaks. When you find small patches of moss, it’s a good idea to have them removed before they become larger and start causing these problems.

How to remove moss from your roof

While a pressure washer can remove moss from your roof, it can also damage your roof. It’s best to have a professional pressure wash your roof to remove moss to avoid major roof damage. When done right, a high-pressure jet of water will lift the moss from your roof. Done improperly, your roof will be damaged or removed along with the moss.

Another option is to scrub the moss from the roof using a broom or brush with stiff bristles and soapy water. While it’s more difficult to damage your roof while removing moss in this way, it’s also a difficult and slow-going job.

If you catch the moss early enough, you can remove it by treating your roof with a solution of copper sulphate. Simply mix 45 litres of water with 2 kilogrammes of copper sulphate and apply the solution to your roof according to the product’s instructions. This will provide enough solution for an average size roof. However, larger or smaller roofs can adjust this recipe to suit their needs.

Stopping moss growth

The best way to stop moss from growing on your roof is to treat your roof with zinc carbonate on a regular basis. If you don’t feel like mixing up a batch and spraying it on your roof regularly, then you should consider using zinc strips. Simply install zinc strips at special places along your roof and wait for rain. Every time it rains, the zinc strips will release zinc carbonate which will wash over your roof. This reduces the amount of future moss growth with one easy installation.

Should you hire someone to clean your roof?

It’s much safer and easier to hire a professional to clean your roof. Scrubbing your roof by hand from a ladder is a precarious task, and improper use of a pressure washer could remove your roof along with the moss, algae or dirt. Instead, most people opt to hire a professional pressure cleaner or a roof maintenance company. Their experience enables them to remove moss with minimal damage to their roof. They’ll also be able to make recommendations for preventing or slowing future dirt and moss build up.