Ultimate Guide to Roof Mold

What is a roof mold?

Are you concerned about the black streaks on your roof, its siding, deck, and patio, but you’re not sure what they are? Most people confuse algae with roof mold so below is a table to properly identify which is which.

algae vs mold

Based on the table above, unlike the algae, mold can cause health problems in the home like asthma, irritated eyes and throat, rashes, fatigue, headaches, and lung issues. That’s why it’s important to identify algae from a mold and determine what exactly the streaks on your roof are.

If the interior of your house is intact or unmarked, you’re more likely just dealing with algae.

Algae don’t harm your roof or your loved ones. They just look bad.

It is best to inspect your crawl spaces, which are the attics and basements a few times every year to be sure mold isn’t silently forming under your nose.

Aside from the signs above, you can spot a mold by looking out for the following:

  • gray or brown ceiling discoloration
  • obvious mold growth (brown, dark green, or black)
  • musty odor near the area of a leak or stain

How to remove them

Prevention is always better than cure

You read it right. The best way to deal with mold is to prevent the growth. You must conduct regular house and roof washes to make sure every part is sparkling and safe.

If ever a mold growth happens in your house or on your roof, it is easier to leave it to the professionals.

However, if you still prefer to ‘do-it-yourself’, you can use pressure washers and soft brushes to get rid of the mold.

Before starting, keep in mind that the most common mistake in using pressure washers in DIY cleaning is applying too much pressure. Aside from damaging your home, you can also hurt yourself when you use too much pressure. Yet, using too little pressure won’t remove the stains.

Then, follow the steps below to remove the mold.

  1. Assess the extent of the damage. Don’t just deal with the visible mold growth. What you see might not be the extent of the growth. Mold grows anywhere with water such as your attic, basement, roof, siding, deck. You should also look out for mold near leaking areas like the ceilings, floorboards, drywall, and insulation.
  2. Remove the mold growth. This only applies to mold growth in a small area. If the growth is too big to manage, call a professional immediately. The first step is to clean the affected area of the roof with a soft-bristled brush. You can also use pressure washers if your roof is not made of asphalt shingles. However, you can use bleach or sodium hypochlorite as a disinfectant on this type of roof.

If the damage is too big, you will need a new roof.

Mold growth is a serious problem and should be dealt with a professional. Moreover, if you do-it-yourself, you might miss spots and just focus on major parts of the roof. Some damage can be intensive and invisible to the untrained eye.

Professionals will not only remove the mold growth but also make sure they don’t come back.




This vital information is from Masterpiece Roofing & Painting, a Denver roofer that specializes in residential and commercial roof replacements, residential and commercial painting, siding, windows and gutter work.

How to Find and Repair a Leaky Asphalt Shingle

An asphalt shingle is a type of wall or roof shingle that uses asphalt for waterproofing and it is the best material you could use for your roofing system. They are available in many colors and are commonly used on sloped roofs, single homes, and small residential projects. An asphalt shingle is very easy and flexible to install.

Roof Leaks are the most hated words by homeowners since the roof is the main protection against harmful external elements. To guarantee that roofing systems are in their best shapes, roof inspection needs to be done at least twice every year, or every time there are shifts in weather cases.

Roofing leaks are caused by:

  1. improper roof installation
  2. wind or storm damage
  3. lack of maintenance

In addition, most roofs can only last up to 20 to 30 years so a leaking roof should be replaced immediately.

Even a small roof leak is critical for an entire building or home because constant water intrusion will move down from the attic to the foundation of the house. This will lead to costly damages you don’t even want to imagine.

How to find a leakage

Water stains that extend across your ceilings or spread down the walls are sure signs of leaks.

The following are the steps to track down a leak:

  1. Inspect the roof from the stains upward. Look for roof penetrations, which includes plumbing and roof vents, chimneys, dormers, or anything else that extends through your roof. You can find leaks just several feet below or at their right or left.
  2. If you can go to the attic, go up that area. Then, use a flashlight to for any evidence, which could be water stains, mold growth, or black marks.
  3. If you can’t access the attic, get up on the roof and inspect it closely.
  4. If still can’t find the source of the leak, hire or find a helper. Get on the roof with a garden hose while letting your helper stay in the house and wait for the drip to emerge. Starting in the lower areas, soak the are right above the leak. Isolate the areas by soaking the downward side of the chimney first, then each side, and the top of both side.
  5. When you find the area near the leak, inspect the shingles in that area. You can also remove the shingles to see if there discolored felt paper or water-stained or rotting wood.

Did you know that roof leaks can destroy insulation, stimulate mold growth, damage ceilings and walls, and cause the wooden framing to rot?

Because of that, it is wiser to repair a leaking roof or let a professional do the job as soon as possible.

Fixing Asphalt Shingles

  • The corners of asphalt shingles begin to curl over time. Smooth out any curled-back shingles carefully. Then, use a caulking gun to dab a roof sealant under the raised corners and press the shingles down. Next, use a trowel to cover the shingle’s edges with roof cement.
  • Shingles become elastic under warm temperatures but they are brittle in colder weather so you may need to soften curled shingles with a blow dryer. However, don’t use torches or more intense heat sources to avoid damaging the shingles.
  • Repair a crack with a bead of roof sealant using a caulking gun. Then, spread the top bead on both edges of the crack using a putty knife. Use asphalt granules accumulations to disguise your repair.
  • To replace broken or missing shingles, hire a professional roofer or buy a matching replacement in the hardware store. To remove a broken shingle, lift the edges of the shingle above it using a pry bar carefully. Remove the nails in the broken shingle’s corners, slide it out, and scrape the area beneath to remove any roofing cement leftover.


This valuable guide is from Calgary Roofing Done Right, your Calgary Roofing Contractor who specializes in working directly with homeowners (not with insurance companies or builders). They also focus on installing asphalt shingles for residential projects.