Chapter 3: Roof Maintenance To Prevent Mold

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What Is The Main Function Of The Roof?

This chapter describes the makeup of a roof and the different components that need to be maintained in order to prevent water, moisture and or mold issues into the home.

The roof acts as a seal on most commercial buildings, or a shedding surface on houses and townhomes.

A flat roof typically contains many layers that must stop moisture or from seeping into the building below.

Sloped roofs act much like an umbrella. They are designed to divert water away from the home or building.

The performance of the roof will affect all parts of the building below. Essentially, the main function of a roof is to protect your home from the weather, especially rain, wind and of course water damage and/or mold inside the home.

What Makes The Roof So Vulnerable To Leaks?

The main reason we get water into the home is from water that seeps inside by roof damage or poor roofing installations. In addition, there are a number of systems inside a home that need to penetrate the roof for the home to function properly.

Although necessary, these systems can leave the home vulnerable to moisture ingress. Skylights and solariums (two commonly problematic roofing installations) will certainly leak when they have been neglected. They need to be inspected both from the inside of the home and the outside, on the roof surface.

In the Pacific Northwest, where I live, we get a lot of rain. During the winter, the continuous freeze-thaw action causes damage to the skylight penetration points, causing them to loosen. When this happens, water will find a way into the home.

To limit the potential of a skylight/solarium leak, be sure to have a skilled and experienced specialist build, and then continue to inspect/maintain them. Besides skylights, we should be concerned with a host of other penetration points, such as flashings, chimneys, vents, valleys, roofing materials and intersection points.

When any of these penetrations are breached, we get leaks and mold inside the home. Here is an excellent resource on a variety of roofing terms for you.

Conditions that cause roof damage and leaks:

All damaged, loose or disconnected roofing components will need to be replaced or repaired. Ideally, these repairs should be completed in the spring or summer in anticipation of the fall and winter rains.

Take a look at the photo of roof damage caused by raccoons discovered during a mold inspection. Thankfully, I was able to alert the homeowner quickly.

Imagine how much water would have poured into the home, if this hole wasn’t caught and repaired in short order?


What Causes Downspouts And Gutters To Fail?

When there is too much debris on the roof, the drains clog up, which causes water to pool along the surface of the roof.

The pooling water actually weighs on the roofing materials, like a mini swimming pool. All of this water weight causes pressure on the roofing materials until it slowly breaks down and causes a leak into the home.

When your gutters and downspouts are damaged, missing, too narrow or clogged, water will overflow, resulting in pooling against the foundation wall, or possibly leakage into the home or attic.

How Gutters And Downspouts Prevent Mold From Seeping Into Your Home

Gutters and downspouts work together to divert and remove large volumes of water away from the home. In order to function properly, all downspouts must be intact and properly connected at the gutters.

The downspouts should lead down into the drainage system below the ground. All drains below grade (underground) need covers to prevent clogging and or flooding.

It is common for your gutters to be clogged with debris or filled with water when they haven’t been cleaned for a few months.

You will need to clean them out at least 2 to 3 times per year, depending on the accumulation of debris from nearby vegetation.

If your home is situated by a forest or greenbelt, you will need to clean the roof, gutters and downspouts more often.

Gutters that are full of water and vegetation are heavy and will eventually come loose. This of course leads to potential water damage.

Is Roof Mold Really A Problem?

The short answer is no. Mold on your roof will not cause problems inside the home.

However, excessive moss growth, sharp twigs, broken trees, water damage, and leaks are much more problematic for the longevity of a roof.

This is especially true with asphalt shingles, for example. Over time the granules fall off the surface. This is bad news as they are meant to protect the roof surface. Take a look at the expired roof shingles in this photo.

So What Can I Do To Prevent This?

Annual inspections by a competent roofing inspector is the best way to keep your roof in good shape. Your roofing inspector will look at the overall performance of the roof and pin-point vulnerable areas along the surface. He will take a look at chimneys, pipe stacks, transitions, penetration points, skylights, valleys, gutters and downspouts.

After the roofing inspection, you can work on an action plan, or schedule so you’ll know what needs to be maintained/repaired and when to do so. The roofing inspector will likely ask you to keep the surface of your roof clean.

For dangerous or difficult jobs, I recommend calling in your roofing contractor to help you. Each type of roof installation and roofing type has different vulnerabilities. It is necessary to know what your roof is made of and how to be proactive when protecting the surface.

Your roof inspector will be able to guide you through this. Since asphalt shingles are one of the most common types of roof installs, I wanted to share a few thoughts on the subject.

Asphalt shingles can be great, and last a long time when installed properly. They are less likely to be invaded by critters compared to clay, shake or shingle roof – they are installed more evenly and tightly.

Moisture accumulation on the surface of your roof leads to algae and moss build up. Moss grows small roots into the surface of the roof, which will accelerate roof damage, while reducing the service life of the roof.

A common solution to prevent moss and roof mold is to use zinc strips. Zinc strips work well as a preventative measure to protect your roof surface. The zinc will effectively kill mold, mildew, algae, moss, lichen, and fungus. Consider this to be a protective barrier for your sloped roof.

There are a number of products that can be used to clean your roof, as well. Check the products section on this site for updates. Oxygen solution products are excellent for roof maintenance. You can clean your roof with Copper Sulphate to eliminate mildew, mold, algae and fungus. Your roof shingles will perform well.

Overall, the most important thing you can do to stop water into the home from the roof is to practice proper maintenance and repair issues as soon as possible.

In the next chapter, we are going to look at attic mold.