Hiring any roof cleaning service might be very expensive, so one question that may come to your mind is – how can you clean your roof by yourself? We’re going to answer that question in this article and give you helpful tips on how you can best clean your roof(DIY) without spending a fortune.

There can be many stains on your roof and every stain has its different cure. In most cases, the below stains can be found on your roof:

  1. Black Stains
  2. Moss Stains

How to Clean Black Stains

Black stains on an asphalt roof are caused by algae. If you reside in a wet area of the country, you’ve most likely seen unpleasant dark streaks on asphalt shingle roofs. Though typically attributed to an accumulation of dirt, defective shingles, mold, or mildew;  the most frequent cause of roofing discoloration is actually a type of bacteria known as Gloeocapsa magma, which is spread through airborne spores.

While algae growth on a roof does little actual damage, the resulting stains can negatively affect the overall appearance and potential resale value of your home.

Areas Liable to Algae Stains

You might have noticed that algae stains are often missing beneath the metal flashing around chimneys and vents. This is because copper and zinc, which are commonly used in galvanized sheet metal, are toxic to algae. Each time it rains, small amounts of these metals are washed down the roof, preventing algae growth.

Algae Resistant Shingles

In recent years, roofing makers have begun combining a mixture of copper granules into roofing products to provide algae-resistant shingles. If you live in a vicinity susceptible to algae lagegrowth, be sure to request these algae-resistant shingles when you are replacing your roof.

Clean Algae Stains With Chemical Treatment

Algae stains can be removed by chemical treatment but they tend to reappear over time. Whereas an occasional improvement won’t hurt your roof, recurrent use of harsh chemicals, or the erosive effects of pressure washing, will harm or shorten the lifetime of asphalt shingles.

Although there are many products on the market specifically designed to get rid of algae stains from roofs, like Wet & Forget Outdoor Cleaner,  a mix of trisodium orthophosphate(TSP), bleach, and water can remove stains. Using oxygen bleach can lighten stains and is less damaging to the environment, but it may not produce results as quickly or dramatically as chlorine bleach.

In addition, the presence of a galvanized vent can inhibit algae growth due to its metal composition.

Required Items

Here’s what you need to get to clean your roof:


Working on a roof is dangerous, and it becomes even a lot more venturesome once wet, thus it requires adequate safety precautions. Avoid cleaning on steep roofs, wear slip-resistant shoes, and use a security rope wherever required. Additionally, when working with harsh chemicals, it’s important to protect your skin and eyes.

Bleach will harm or kill alternative plants besides the algae, thus wetting down any grass, shrubs, or other plants wherever runoff may occur before and after applying bleach is necessary. Covering bushes with plastic after moistening them can also provide extra protection.

Cleaning Method Number 2

It’s best to scrub your roof on a cloudy day to prevent the cleaner from evaporating too quickly. If you recognize the manufacturer of your shingles, contact them or check their website for specific recommendations on improvement. When using a commercial roof cleaning product or oxygen bleach, be sure to follow the instructions provided on the container.

While the formula for cleaning a roof with bleach can vary, a basic solution is:

  1. 1-quart bleach, 6% Sodium Hypochlorite(NaOCl)
  2. 1-gallon water
  3. 1/4 cup of trisodium phosphate(TSP) or alternative heavy-duty cleaner (don’t use a cleaner that contains ammonia or isn’t suggested for commixture with bleach, as they can produce toxic chlorine gas)
  4. Pour the ingredients into a pump-sort garden sprayer, mix well, and spray.

Once you have applied the solution to the roof, let it sit for about 15 minutes, then rinse off with a hose.

Moss Stains

Greenery overhead should be limited to leaves emerging from tree canopies. If mossy foliage is furnishing your roof, it’s time to start cleaning.

Moss grows in areas untouched by the sun, thus it will develop at a speedy pace on tree-shaded and north-facing roofs. Spreading moss will quickly cover roof surfaces, filling in voids between shingles and tiles and reaching underneath and lifting roofing materials. The lifting of shingles permits rainwater and other moisture to flow into a roof’s structure causing decay and deterioration.

Before you clean moss off a roof, you will need to think about how you would kill the plants and remove the dead layers of moss. Later, you’ll need to implement some preventive measures to prevent it from gaining future toeholds.

Experts recommend saving roof moss removal for a cloudy day. Roof-cleaning products, which should soak into the moss and algae for at least 20 minutes, won’t evaporate as quickly as they might on sunny days. Moss can be removed physically (with water and a stiff brush), chemically, or by using a combination of both methods.

Use the least-toxic moss killer;  chemical solutions can harm the environment and potentially damage vegetation under the roof overhang. If you choose to use a bleach solution or alternative readymade roof moss treatment, protect nearby plants with plastic cloth. It is also a good idea to pre-wet plants, shrubs, and tiny trees with water—the coating of water can dilute chemicals spilling downward from the roof overhang.

Some readymade cleaners—like Wet and Forget Outdoor Moss, Mold, Mildew, and Algae Stain Remover—can be mixed and applied per the manufacturer’s directions and left to kill the algae with no removal needed. Others, like Bayer’s 2-in-1 Moss & Algae Killer, are often available on the market in ready-to-go sprays that attach to your hose. Be careful to follow the mixing and application recommendations to ensure your safety and prevent damage to roof tiles, shingles, and nearby plants.

Alternatively, you can create a less toxic moss remover—which is typically less toxic than its chemical counterparts. Chemical bleach removes mosses, fungi, and mildew, however, it can be harmful to plants if not diluted properly. Combine one quart of bleach with one gallon of water and ¼ cup of industrial quality cleaner like trisodium orthophosphate(TSP) (don’t use ammonia-based cleaners as they produce nephrotoxic fumes once mixed with bleach).

Or, for a plant-friendlier solution, mix one cup of bleach and one liter of water. Home improvement expert Bob Port Vila suggests combining eight ounces of Dawn Dishwashing Liquid or 1½ to 3½ cups of white distilled vinegar with two gallons of water. Pour solutions into a pump garden-style sprayer; a backpack sprayer can be safer to use if you’re climbing and standing on a ladder.

Once you have selected your moss-removing solution, it is time to get started. Follow the step-by-step guide to remove moss and other debris accumulated atop your house!

The Eco-friendly, Non-bleach, Low-Pressure Roof Cleaning Method

Roof cleaning companies that use this technique use top-grade eco-friendly products that don’t contain nephrotoxic chemicals like chlorine bleach, phosphates, or alternative chemicals that may kill vegetation and bemire waterways. Additionally, this method uses a low-pressure rinsing system, avoiding the use of high-pressure washing or brushing.