How To Remove Lichen Off Your Roof

How to Easily Remove Nuisance Lichen Off Your Roof

If it seems like a never-ending battle between your scrubbing brush and the lichen on your roof, this article is for you. While you may think scrubbing and scraping is the answer, let us introduce you to our biodegradable Wet & Forget Exterior formula perfectly fit for the job - with no scrubbing required.

Before we get into this convenient process, let's sum up what lichen is and how it can damage your roof.

What is Lichen?

Lichen is a Waxy Growth That Looks like  Cauliflower

Lichen is a hard, crusty, leaf-like growth that is made up of fungus and algae. It can take the form of many colours, with its appearance ranging from green to grey to orange. Beyond its colour variation, there are three main types of lichen; foliose, fruticose, and crustose.

  • Foliose lichens can be rigid, leafy or flat and have a distinct bottom and top.
  • Fruticose lichens often resemble shrubs or corals with round or flat branches.
  • And crustose lichens often appear as patches with a crusty top layer.

For more information about the different types of lichens, check out the Lichens of New Zealand Guide.

What Causes Lichen to Grow on My Roof?

For lichen to grow, it simply needs fresh air, water, and sunlight - all of which it can easily find on your roof. As a result, your roof is highly vulnerable to becoming covered with lichen.

Is Lichen on My Roof Damaging?

When lichen is left untreated, it can cause some serious damage to your roof. 
Removing Lichen Protects the Longevity of Your Roof

Removing Lichen Protects the Longevity of Your Roof

Firstly, lichen holds moisture against the surface. When this moisture is exposed to cool temperatures it can then freeze causing the roof shingles to bend, warp, shift, or crack. From this, the life-span of your roof may drastically decrease.

The build-up of lichen on your roof may also affect the gutters ability to manage rainfall. As a result, you could end up with blocked gutters or a leaky roof.

Another major factor to consider is the unattractive appearance of lichen. If you're selling your house in the near future, keep in mind that potential buyers will be discouraged by the presence of lichen on the roof. As not only does it look bad but it indicates that they’ll likely have to perform repairs, ultimately decreasing the value of your property.

For those who aren’t planning on selling anytime soon, you’ll still probably want your house to look good - which is yet another reason why the lichen has got to go.

How do I Remove Lichen Off My Roof?

Due to its fungus-algae make-up, lichen can be an absolute nightmare to remove. Although you can attempt to scrap and brush away the growth, this can be an insanely time-consuming process nor very effective - as even if you've removed all visible lichen, smaller patches of the growth will cause it to grow back quickly.

Plus, by brushing or scraping the lichen, you also risk damaging the top layer of the roof (and trust us you’ll need to brush very hard in an attempt to remove this crusty concrete-like growth).

So, what’s the alternative?

Good news!  Our non-acidic, non-caustic, bleach-free Wet & Forget formula offers a convenient and safe alternative cleaning method.

How does it work?

Get Rid of Nuisance Lichen

When the Wet & Forget formula is applied to the roof, it begins to remove the dead lichen. Each time it rains, the effective combination reactivates helping to eliminate the growth without having to whip out your scrubbing brush - which makes the cleaning process, a whole lot easier.

Our Wet & Forget Outdoor formula is available as either a 5L Concentrate or a ready-to-use Rapid Application. Although the dilutions are different, both products have identical ingredients and give exactly the same coverage.

If you’re using the 5L Wet & Forget Concentrate you’ll need to complete the following steps:

  1. Choose a cool, dry day to apply the product (where no rain is predicted for the first five hours).
  2. Mix one part Wet & Forget to five parts water in a garden sprayer - e.g. 1L Wet & Forget to 5L water.
  3. If you have lichen, visualise the different sections of the roof you need to spray. Work to a pattern and spot spray the lichen in each section. This will help to soften the lichen’s outer shell. Respray the whole area again after about 15-20 minutes. 
  4. Completely saturate all these sections with the product.
  5. Let mother nature do its thing.
  6. Treat in a year or at first sight of re-growth.

Alternatively, if you’re using the Wet & Forget Rapid Application, you’ll need to complete the following steps:

  1. Choose a cool, dry day to apply the product (where no rain is predicted for the first five hours).
  2. Attach your hose and get ready to spray.
  3. If you have lichen, visualise the different sections of the roof you need to spray. Work to a pattern and spot spray the lichen in each section. This will help to soften the lichen’s outer shell. Respray the whole area again after about 15-20 minutes. 
  4. Completely saturate all these sections with the product.
  5. Let mother nature do its thing.
  6. Treat in a year or at first sight of re-growth.

The Rapid Application reach nozzle offers up to an 8-metre reach, which means you can spray the lichen without having to use a ladder.

Tips for Application

  • As mentioned above, you’ll want to select a cool, dry day to apply Wet & Forget. To do so, you need to check the weather forecast and ensure no rain is predicted (or at least for the first five hours). Often, it’s best to spray your roof in the morning or evening when the temperature is at its lowest.
  • When applying Wet & Forget, make sure to thoroughly saturate the entire roof, to ensure that the product has reached every growth.
  • Make sure the surface is dry to avoid evaporation. If the surface is heavily covered in lichen, you will benefit from reapplying the product one month after the first application.
  • Remember to be patient when waiting for results. Generally, you can expect it to take two-three months, but this will differ depending on the amount of lichen.
  • On the topic of time, don’t wait until your roof is completely covered before taking action. The longer you wait, the more damage you risk.
  • For those using a garden sprayer and ladder, be mindful of where you’re placing your ladder. For more information about using a ladder safely, check out ACC’s ladder safety guide.

Ready, set, clean!

We hope you’re feeling more knowledgeable and ready to say goodbye to that awful blanket of lichen on your roof. If you have any more questions, don't hesitate to contact us using our online forum.  For those ready to start cleaning, find your closest retailer using our Store Locator or buy online today.