How to Prevent Moss on Roof Growth

What You'll Need
Wood saw
Zinc strips

Anyone who lives in a damp climate will already understand the implications of moss on roof problems. Adverse weather has a tendency to attract moss onto the shingles, and it soon begins to looks ugly. Eventually, you will have to climb up to the roof to remove the moss yourself. This is something that you will usually need to do a couple of times a year if you have a big problem and removing moss is an awkward and potentially dangerous chore. Wouldn’t it be better if there was a way to stop moss forming on the roof in the first place?

Step 1 - Understanding Moss

Moss is a plant without roots. This means that it needs flowing water in order to reproduce and survive and provides a great indication as to why you won’t find moss on an area of a roof that receives a large amount of sun. Although mosses are vital to ecosystems, they’re not particularly vital to roofs.

In fact, moss can cause lasting damage to a roof over the course of several years as it grows between the standard composition shingles.

Step 2 - Eliminating Moss

Before you can begin the ongoing prevention of moss from your roof, you will first need to get rid of the moss that’s already there.

The simplest way to do this is to climb onto the roof with a length of hose attached to a water source and wash the moss off. Most of it should come off quite easily although you might have to scrape out a few stubborn areas using your scraper. Start near the peak of the roof and work you way down to avoid damaging the shingles. If you’re uncomfortable on the roof, or if the pitch of the roof is too steep, you might want to hire a professional for the job. Be aware that some of that moss will fall into your gutters which means you’ll need to clean those out too.

Step 3 - Keeping the Moss Off

The more sun that can reach your roof, the less moss you will have there. Your first job should be to cut down any branches that overhang and shade your roof. A wood saw is ideal for this task.

If you’re considering a new roof, look into having a metal roof added to your home. Moss does not stick to metal. Unfortunately, the main problem is that a metal roof will cost a great deal more than a new shingle roof. However, this is offset by the fact that a metal roof will rarely need to be replaced. If you’re intending on keeping your house for many years, the costs could end up around the same.

Step 4 - Using Chemical Bases

Zinc is very good at keeping moss of roofs. You have 2 alternatives available when using zinc.

  • The first is a pesticide which you can buy in most hardware stores. This has zinc sulphate among its active ingredients. The problem with this is that zinc is water soluble and in large quantities, it can be highly toxic. It will keep the moss off your roof, but it will eventually run into the ground water.
  • A better choice is zinc strips. These are, on average, around 3 inches wide and you can nail them a little below the peak of the roof. As rain crosses the zinc, it dissolves a little of it and helps keep the moss away. The quantities are so small that there’s no need to worry about toxicity levels.