How To Clean Your Walls In A Weekend: The Easy Guide

How To Clean Your Walls In A Weekend The Easy Guide

You are concerned about the dirt on the exterior walls of your house, but “I don’t know how to clean the exterior walls,” or “Won’t the dirt on the exterior walls come off without a high-pressure washer?” I am sure you are concerned about it.

However, you can start cleaning the exterior walls with tools you already have at home. Here, we will introduce how to clean the exterior walls by yourself and some points to keep in mind when cleaning.

By regularly cleaning without leaving dirt behind, you can delay the life of the exterior walls (prevention of deterioration), so please put it into practice.

However, it is best to ask a contractor to clean the exterior walls at high places because it is dangerous to do it yourself. Please refer to this page for a list of prices and other information!

Exterior Walls Will Accumulate Dirt and Deteriorate if Not Cleaned

If exterior walls are left uncleaned, they will become dirty as dirt from outside gets on them, and the outer walls deteriorate.

Let’s look at the causes of dirt on exterior walls and how not cleaning them can affect your home.

Causes of Staining on Exterior Walls

Although the causes of staining vary depending on the type of exterior wall and the environment in which the house is built, the following are the causes of staining of exterior walls.

Dust and DirtIt easily adheres to uneven exterior walls, making the house look gray, brown, black, and dull. The black outer wall stands out.
Exhaust GasSoot-like greasy stains appear over a large area, making it look dull and black. The white outer wall stands out.
MoldOccurs in areas with poor sunlight and airflow, such as the north side of a house. The white outer wall stands out because of the black dirt.
Moss/AlgaeOccurs in moist and sunny areas. green stain. It is more likely to occur near mountains.
RaindropDirt dripping under window sashes and vents. Dirt that has been washed away by the rain has accumulated under the protrusions. If you leave it alone, it will settle and become difficult to remove.
RustIt tends to occur on siding outer walls. Be careful as the red rust will move to other places.
Paint DeteriorationExterior wall paint deteriorates and fades due to long-term exposure to ultraviolet rays. If chalking occurs, immediate repainting is required.

The exterior walls of many homes become dirty from dust, dirt, and exhaust fumes. Depending on the location, mold, moss, and algae can develop and take root deep in the exterior walls.

If the walls have not been repainted in the past ten years, the paint may have deteriorated and cracked, allowing rainwater to seep through.

In the case of exterior siding walls, metal is prone to red rust as the coating deteriorates and rainwater seeps in.

Red rust can transfer to other areas and cause rusting, and red rust stains can be notorious even on non-metal sites.

Exterior Walls in These Environments Are Easily Stained

  1. Uneven exterior walls are prone to dust and dirt.
  2. White or black colored exterior walls quickly show dirt.
  3. Heavy traffic exhaust fumes easily stick to it.
  4. Facing north and close to mountains, mold, moss, and algae are easy to get on.

There are various types of exterior walls, including those that are stain resistant, but the outer walls listed above are relatively easy to stain.

If Left Untreated, It Will Deteriorate Faster

If you leave exterior walls uncleaned, dirt will settle in and become more difficult to remove, requiring more effort.

It takes more time and effort to clean, but not cleaning the exterior walls also means not maintaining them.

If you fail to notice even minor abnormalities in the exterior walls and leave cracks and deteriorated paint, rainwater can enter, causing mold and wood to corrode.

If this gets into the house’s interior, it will be unsafe to live in, and attempts to repair it will cost tremendous money! It is essential to clean and maintain the house regularly to prevent this from happening.

Tools Needed for Cleaning Exterior Walls

A high-pressure cleaner helps clean exterior walls, but you can also use tools you can prepare at home.

What to prepare

  • Soft sponge or brush (suitable for high places)
  • Bucket
  • Rubber gloves
  • Hose
  • Detergent as needed (mold, moss remover, etc.)
  • High-pressure cleaner (if available)

Since water and dirt will splash around when cleaning exterior walls, please be sure to wear clothes that can get dirty.

Also, prepare detergents and high-pressure cleaners according to the condition of the exterior walls (materials, etc.).

How to Clean an Exterior Wall


The following is an introduction to cleaning the exterior walls yourself. It takes time and effort but is less expensive than hiring a contractor. If you are good at DIY, or if the stain is partial, we recommend you do it yourself.

Cleaning Procedure

  • Check the condition of the exterior walls
  • Curing the surrounding area
  • Wash the exterior walls with water
  • Scrub mold and moss with a sponge or brush
  • Rinse with water

Check the condition of the exterior walls.

Before starting to clean the exterior walls, check the exterior walls themselves for cracks, chips, or other areas that need to be repaired.

Curing the surrounding area

Since water and dirt will splash around when cleaning the exterior walls, protect your neighbor’s house and other areas where you do not want them to fly away in advance.

Rinsing of exterior walls

First, wash the exterior walls with water. Most of the dirt can be removed here if your home has a high-pressure washer.

Scrub off mold, moss, and stubborn stains.

For mold, moss, and stubborn stains that cannot be removed by washing with water, scrub with a sponge or brush. Mold and moss can also be cleaned off by using an appropriate detergent.

Rinse with water

Finally, rinse the exterior walls with water to finish the process.

Exterior Wall Cleaning Precautions

Some people use ladders or stepladders for high areas when cleaning exterior walls. Still, it is perilous for amateurs to do so because it is difficult to even for contractors (see: fatal accidents due to falls).

When cleaning high points on exterior walls, ask a professional contractor to do the work.

Do not scrub exterior walls rigid (coating will come off).

The material of exterior walls is coated to resist stains, so be careful not to scrub hard. In particular, the joints are vulnerable to irritation and will be torn to pieces if rubbed hard.

Use high-pressure cleaners with caution.

High-pressure cleaners are powerful but can cause noise, splashing, and damage to exterior walls.

It is a good idea to inform your neighbors about the noise and splashing and to protect your property.

Do not keep hitting the same spot to avoid damaging the exterior wall, and if you can adjust the pressure, try using weak force while removing it.

Protect the skin from detergents

Some detergents used to remove stains from exterior walls can be very irritating. When using detergents, please wear rubber gloves to avoid contact with your skin and be careful of splashing dirty water.

Cleaning Methods Suitable for the Material of the Exterior Wall

Cleaning methods vary depending on the exterior wall, and amateur judgment can harm the life of the outer wall. When cleaning by yourself, please pay attention to the material of the exterior wall.

Tile exterior walls

Tile exterior walls are durable, water-resistant, low-maintenance, and robust and can be washed with a brush or high-pressure washer. Since they are not painted, exterior wall cleaning detergents can be used without paint deterioration. However, some chemicals may cause exterior walls to become dull and white, so check the tile material carefully and test it in an inconspicuous area before use.

Siding exterior wall

There are different types of exterior siding: ceramic siding, metal siding, wood siding, and resin siding. About 70% of Japanese homes are built with ceramic siding, which is superior in cost, functionality, design, fire resistance, and earthquake resistance.

The surface of exterior siding walls is coated, so cleaning with brushes, high-pressure washers, or other strong irritants will shorten the life of the exterior walls. Use a soft sponge and weak water pressure to wash.

Mortar exterior walls

Although many types of mortar are now available that are less prone to cracking, mortar is still more prone to cracking than other exterior wall materials. When cleaning, wash with a soft material or flush with weak water pressure.

If cracks have developed, cleaning will allow detergent and water to get into the cracks, causing mold and corrosion. If the cracks are significant, it isn’t easy to repair them, so ask a contractor to fix them before cleaning.

Frequency and Timing of Exterior Wall Cleaning

These days, most exterior walls are stain-resistant, so there is no need to clean them as long as the stains are not noticeable. When stains become noticeable, check and clean them once or twice a year. If the house has not been cleaned in the ten years since it was built, it is recommended to clean it immediately.

When cleaning, check the exterior walls for any abnormalities. If there are cracks or other fissures, water may enter the house during cleaning, so repair the exterior walls before cleaning or leave it to the contractor.

After Cleaning the Exterior Walls, Let’s Waterproof Paint Them to Prevent Stains!

When cleaning exterior walls with a high-pressure cleaner, the protective coating on the surface of the exterior walls may be removed. This makes the exterior walls susceptible to dirt even after they have been cleaned, so it is recommended that a protective coating be applied after high-pressure cleaning.

Waterproof coating after high-pressure cleaning

Most exterior walls are coated with a protective coating to repel dirt. Over time, the antifouling effect gradually wears off, and the use of a high-pressure cleaner can hasten its lifespan.

If the exterior walls are not cleaned with a high-pressure washer before the waterproof coating is applied, the walls will be more susceptible to staining because they are less able to repel water, and the water will seep through and cause mold and moss!

If mold and moss get deep into the building materials, they will rust, affecting the house’s life.

Apply low-staining paint

When painting after cleaning exterior walls, it is recommended to use “low-staining paints” that are stain resistant. Low-staining paints are as follows.

Choose a color that does not show stains easily.

Although it is essential to choose paint with antifouling and self-cleaning effects, if the color of the exterior wall is conspicuous, the stain will eventually stand out.

As mentioned at the beginning of this article, most stains on exterior walls are black or green. Depending on the environment of the house, black mold can quickly grow, and if the house is near a mountain, green moss will adhere. However, making stains less noticeable can make it harder to notice mold and deterioration, so be sure to check and maintain your colors regularly.


We have learned that you can clean your exterior walls yourself as long as you take precautions for safety and use cleaning methods appropriate for the materials of your exterior walls.

The antifouling effect begins to fade after about 5 to 7 years of construction, so check the exterior walls twice a year starting about this time. Please ensure no cracks or other damage before cleaning the exterior walls, as this can cause mold and corrosion. If you cannot clean it yourself, such as in high places, we recommend hiring a contractor, although it will cost more. If it has been almost ten years since the house was built, it will require maintenance, so it is a good idea to have it cleaned and repaired.

If you choose the color of the exterior wall based on the characteristics of your area and the type of dirt it is prone to, the dirt will be less noticeable.

Please use this article as a guide for cleaning, keeping your exterior walls beautiful, and protecting your lovely home for a long time!