How to Clean Mold Off Your Gutters

Man and Woman cleaning mold from gutter

Gutters are great at keeping your home’s foundation free from moisture, but over time they collect grime and mildew. Fortunately, getting rid of this filth is not that hard. Let’s dig in, see what you’ll need, and how you can clean mold off your gutters without damaging them. 

In this article:

Why Do Gutters Get Mold?

White Gutter
Photo by: pointnshoot – Flickr – CC BY 2.0

Mold is a fungus that grows in damp, warm, humid conditions. It spreads by water, air, and insects and multiplies at a super fast rate through spores. When your gutters start to collect moisture and debris, it creates an ideal breeding ground for mold. Mold starts to grow beneath your gutters and slowly develops a grimy coat all over them. Generally, there are three main reasons why this would happen:

  1. Your gutters are old
  2. Gutters are not installed properly
  3. Gutters are not maintained adequately

Gutters tend to get clogged with leaves, dirt, and other debris cascading down the roof. If they’re not regularly cleaned and unclogged, they collect organic matter. Such buildups trap moisture and offer excellent growing conditions for mold spores.

Homeowners who have old and aging gutters need to be more careful. Older gutter installations have segmented pieces and they lack proper air circulation to keep the gutter dry. As gutters age, the connections start loosening and create small gaps. 

These gaps eventually fill with plant matter and collect moisture, making the perfect environment for mold growth. 

The same happens when your gutters aren’t installed properly. Small gaps can trap dirt and moisture, and invite mold.

What Happens to Moldy Gutters?

A few dangers of mold formation on your gutters include:

  • Mold leaves stubborn stains and other cosmetic damage to your roofline, soffits, and fascia.
  • It weakens shingles and seeps into the structure.
  • Mold dampens interior walls and damages paint.
  • It rots wood. If your house has a wooden foundation, clogged, moldy gutters are a huge concern.
  • Moldy gutters make cozy living spaces for ants, termites, roaches, mosquitoes, and other insects. You will likely be dealing with a painstaking infestation if your moldy gutters are left unattended. 

How to Clean Mold Off Your Gutters

Cleaning gutters is an unpleasant chore. Many homeowners leave that to professionals, but with the right tools and instructions, removing mold is not too hard. Let’s see what you’ll need for this DIY job:

Materials and Tools You’ll Need

Here’s what you should have:

  • A sturdy ladder
  • Gloves and goggles
  • Adequate clothing (shirts and pants should not be loose as they can snag and cause falls)
  • Garden hose
  • A scrubbing brush and scoop
  • Bleach 
  • Sprayer 

Safety Precautions

  • Place your ladder on a stable, flat surface to keep it from shifting or wobbling. Always use a ladder stabilizer if you’re working over a window.
  • Do not attempt to stretch or overreach when you’re on the ladder. You can easily lose balance and injure yourself. Instead, get down and move the ladder every few feet as you clean.
  • Wear protective clothing that fully covers your body.
  • Wear non-slip shoes or boots so there’s no risk of slipping.
  • Schedule your gutter cleaning for a dry, sunny day because working in wet conditions can be risky.
  • Use safety glasses and gloves to protect your eyes from the cleaners, insects, dirt, small rodents, sticks, and animal waste.
  • Work with a spotter.  

Step-by-Step Instructions to Clean Mold From Gutters

Here are simple steps to remove mold from your gutters:

  • Prepare the Potion: Mix one part bleach and three parts warm water. The amount of mixture needed depends on the length of the gutters. You might need two rounds of this if the gutters are caked in mold. But keep in mind that increasing the potency of your mixture won’t make much difference, so it’s better to stick with safe amounts of bleach in your mix. Add this cleaning solution to a spray bottle. 

Note: This solution can also be used to remove oxidation

  • Ascend the Ladder and Scoop the Debris: Climb up the ladder and remove the gutter guards, if there are any. Then, use a gutter scoop to remove leaves and other debris from the gutter. Work from the corners toward the center so you don’t clog the downspouts in the process. Scoop debris from one corner to the middle, stop, shift to the opposite corner and work toward the middle again. Collect all the debris in a bucket. 
  • Rinse: Once you remove all the debris, rinse your gutters thoroughly with a hose. Some people also use pressure washers, but pressure washing can damage gutters and weaken connectors. 
  • Spray All Mold-ridden Areas: The first spraying is supposed to kill and weaken the mold rather than remove it. Use an extendable sprayer and douse all moldy parts of your gutter. SAFETY NOTE: Remember, that this solution includes bleach, which can be harmful to eyes and skin. Wear goggles, gloves and protective clothing.
  • Let It Sit: Wait 10-15 minutes for the bleach mixture to settle in.
  • Scrub, Scrub, Scrub: Use a scrub brush and douse it in the cleaning solution. Get up the ladder and thoroughly scrub the mold until it’s completely off the surface. Make sure you don’t scrub too hard or apply too much pressure as it can warp, loosen or break the gutter connections. 
  • Spray Again: This time, rinse the problem areas of the gutter with your bleach solution. Most of the mold should be gone by now, but the rinse will kill the remainder that you might’ve missed while scrubbing. 
  • Wait and Give a Final Rinse: Let the gutters soak for another 15-20 minutes after you apply the bleach mixture. Scrub off if there’s still any mold visible and then rinse with the hose. 

The Best Time to Clean Mold Off Your Gutters

Ideally, you should clean your gutters twice a year, once in fall when all the leaves have fallen, and then again at the end of spring. But don’t wait. If you notice a growing buildup, break out the bleach and hose. 

Fall and spring produce the most debris – leaves, acorns, and dead tree limbs. Spring also fills gutters with pollen, fallen flowers, and seed pods. So, this recommended declogging and cleaning timeline makes sure that you remove the maximum debris.

Spring and fall are also perhaps the wettest times of the year, which is ideal for mold formation. And if you clean your gutters at the beginning of these seasons, they will back up in no time. 

Frequently Asked Questions

Can you permanently remove mold from gutters?

No. Mold will return whenever the environmental conditions are favorable, i.e., moist, damp, and humid. 

Are mold and mildew the same?

Mold refers to all species of microscopic fungi that grow in hyphae, the multicellular filaments. Mildew refers to a specific kind of fungus or mold. It’s often generically used for mold with flat growth habits. 

The Final Word

This detailed guide will help you clear up all the gunk from your gutters and keep them looking sharp. But if you don’t like to get your hands grimy, call in one of our home improvement experts for their exceptional cleaning services. 

Main Photo by: Picryl


Farah Nauman

Farah Nauman is a freelance writer and an accountant based in Pakistan. She spends most of her time combating the South Asian heat and being a mom to her three fluffy cats and a dozen little Aloe Veras in her house.