Exterior Wall Painting

How Do I Clean The Exterior Wall Before Painting?

So you’ve finally decided to give your exterior walls a fresh coat of paint. Congrats! A new paint job can do wonders for your home’s curb appeal and make the whole place feel new again.

But before you start slapping paint on the siding, there’s an important first step: cleaning the walls. If you want your new paint to adhere properly and look its best, cleaning and prepping the walls is essential.

Dirty, grimy siding won’t give you an attractive end result no matter how much time you spend painting. The paint won’t stick as well to dirt and debris, and any imperfections on the wall will show through.

But don’t worry, cleaning your exterior walls before painting isn’t difficult. With a little time and the right approach, you’ll have your siding looking fresh and ready for its close-up in no time. So grab your cleaning supplies, turn on some tunes, and let’s get scrubbing! By the end of this, your walls will be sparkling clean and primed for a flawless new coat of paint.

Clean Walls Thoroughly

The key to a smooth paint job starts with a clean surface. Give your exterior walls a good scrub down before you even think about picking up a paintbrush.

First, use a pressure washer or hose to remove any loose dirt or debris. If there are any areas of stuck-on grime, scrub them off with a degreaser and stiff brush. Rinse well when done.

Next, inspect the walls for any cracks, holes or damage and patch them up. Caulk around windows, doors, siding, and trim to seal any gaps or seams. This prevents moisture from getting in and also provides a smooth base for your topcoat of paint.

Now give the walls a once over with sandpaper or steel wool, roughing up the surface a bit. Wipe away dust with a tack cloth. This light sanding helps the new paint adhere better.

Before painting, clean the walls one more time with a mixture of detergent and water or a specialized wall cleaner. Use a sponge or scrub brush to remove any remaining dirt or debris. Rinse with a hose and let the walls dry completely.

Repair Any Damage to the Wall Surface

Before you can start painting, you need to thoroughly clean the exterior walls to provide a good surface for the paint to adhere to.

Inspect the Wall Surface

Walk around the entire exterior of the house and inspect the wall surface closely. Look for any damage like cracks, holes, or peeling paint that needs to be repaired. Check places where water may have caused damage like near gutters or downspouts. It’s best to do repairs before cleaning and painting for the best results.

Remove Loose Paint and Debris

Use a putty knife, wire brush, or paint scraper to remove any loose paint, dirt, or debris from the surface of the walls. Be very thorough, as anything left on the wall can affect how well the new paint adheres. Wipe away everything with a tack cloth to leave a smooth, clean surface.

Clean and De-Gloss the Walls

Scrub the entire wall surface with a detergent and water using a scrub brush to remove built-up grime and de-gloss the walls. Rinse well with a hose to remove all dirt and residue. Let the walls dry completely before painting. For glossy walls, you may need to lightly sand to rough up the surface so the new paint has something to grip onto.

Seal any Cracks or Holes

Inspect the walls again for any cracks, holes or imperfections and seal them with caulk, spackle, or concrete patch compound, depending on the material.

Let all sealants dry as directed before painting over them. Your exterior walls are now clean and prepped, ready for a new coat of paint! With the proper cleaning and surface preparation, your paint job will last for years to come.

Remove Loose Paint and Debris

Once you’ve cleaned the exterior walls, it’s time to remove any loose paint or debris before painting. This step is important to ensure good adhesion of the new paint coat.

Remove loose paint

Use a putty knife, wire brush, or paint scraper to remove any loose, peeling, or bubbling paint. Work slowly and carefully so as not to damage the surface underneath. For large areas of chipping or peeling paint, you may need to use an electric paint stripper, heat gun, or chemical stripper to fully remove it. Make sure to clean the area thoroughly after stripping the paint.

Any remaining loose paint will prevent the new paint from properly sticking to the wall surface. Take your time to do a thorough job. It may feel tedious, but your patience will pay off with a smooth finished look.

Clean debris

Wipe down the entire wall surface with a damp rag to remove dirt, cobwebs, and other debris. For stuck-on messes, you may need to scrub a bit harder. Use an old toothbrush to clean cracks and crevices.

Rinse the wall with water to wash away remaining dirt and grime. Let the wall air dry completely before painting.

•Remove cobwebs in corners and eaves with a broom. Vacuum surfaces if needed.

•Clean mildew or mold with a bleach solution. Rinse well with water.

•Remove any nails or staples and patch holes with spackle or caulk.

•Wipe away chalk marks, crayon, or other stains. An abrasive sponge may be needed.

•Sweep porches, patios, and walkways surrounding the wall to remove additional debris.

Scrub Away Built-Up Grime and Mold

The exterior walls of your home take a beating from the elements, accumulating built-up grime, mold, and mildew over time. To ensure the best results from your paint job, you’ll need to thoroughly clean the walls first.

Use a pressure washer or garden hose to spray away loose dirt and debris. For stuck-on messes, make a cleaning solution of detergent (like dish soap) and water. Use a scrub brush to loosen caked-on grime and stains. Rinse well with water to remove all remaining detergent residue.

Check for any mold or mildew spots, especially in areas that don’t get much sun. Mix one part bleach to three parts water and scrub the moldy areas with the solution. Rinse completely with water after a few minutes. Be very careful using bleach, as it can damage plants and the surface below. Ventilate the area and consider wearing gloves and eye protection.

Look for any cracks, holes or damage in the siding or stucco and make necessary repairs. Seal or patch these areas so you have a smooth surface for the new paint to adhere to. Caulk, wood filler, or concrete patch compound can be used, depending on the surface material.

Rinse the Walls With a Power Washer

A power washer is the best tool for thoroughly cleaning exterior walls before painting. Rinsing with a power washer removes built-up dirt and grime, loose paint chips, and debris that could affect how well the new paint adheres.

To rinse with a power washer, first set it to a low pressure setting, around 500 to 800 PSI. Start at the top of the wall and work your way down using even, overlapping passes. Keep the wand 6 to 8 feet from the surface as you work. At a lower pressure, the power washer will clean the wall without damaging it.

Pay extra attention to any spots that look particularly dirty or where the existing paint looks loose or chipped. Go slowly over doors, windows, gutters, and trim to avoid damaging them. Rinsing these areas is important since the new paint needs to adhere properly in order to protect from water damage.

For stubborn dirt or stains, increase the pressure in small increments, but never go above 1500 PSI. Be very careful if increasing the pressure, as higher settings can potentially damage the wall surface. An alternative is to pretreat any stubborn stains before power washing. Let any pretreatment soak in as directed before rinsing.


So there you have it, a few tips to get your exterior walls squeaky clean before painting.

While it may seem like a tedious task, taking the time to properly clean and prepare the surface will make a huge difference in the end result. Your paint job will last longer and look more professional. Get out there on a nice day, turn on some tunes, and get scrubbing.

Before you know it, you’ll be rolling on that first coat of paint and seeing your house transform before your eyes. A little elbow grease now means enjoying your freshly painted exterior for years to come. The effort will be well worth it!

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Advanced Painters

Advanced Painters are professional painters and decorators in the Home Counties. From exterior painting and rendering, to uPVC window spray painting and interior decorating, we produce high quality finishes that will transform the appearance of your property.

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