Home & Building Care · 7 min read

Can You Pressure Wash Brick? How to Clean Brick Homes and Buildings in Charleston Without Damaging Them

Brick is one of the most durable materials on a Lowcountry home or commercial building. It is also one of the easiest to damage with the wrong cleaning method. A high-pressure pressure washer can strip the face off a brick, wash out mortar joints, and leave permanent lines that look worse than the dirt ever did.

So, can you pressure wash brick? The short answer is: only with low pressure, the right nozzle, and the right cleaning solution. This guide explains what the brick industry and the National Park Service actually recommend, what is growing on your brick, and how to get it clean without shortening its life.

Brick has a faceThe fired outer surface is worth protecting.

Joints matterToo much pressure erodes mortar.

Gentlest methodIndustry guidance starts with the least aggressive option.

Older is softerHistoric brick needs extra care.

What the Experts Say About Pressure Washing Brick

The Brick Industry Association's Technical Note 20, Cleaning Brickwork is the standard reference for cleaning brick. It defines pressure ranges and is clear about where the line is:

Pressure Range (BIA definition)	PSI	Guidance
Very low pressure	Under 100 psi	Used for pre-wetting the wall before applying a cleaner
Low pressure	100 to 400 psi	Used for rinsing
Medium pressure	400 to 800 psi	May be appropriate for some brick, only if the brick manufacturer permits it
High pressure	Over 800 psi	Not appropriate for brick and may damage the brickwork

The same technical note recommends a 25 to 50 degree fan tip held at least 12 inches from the brick, and says not to exceed 400 psi at the nozzle unless the brick manufacturer allows it. For comparison, many consumer gas pressure washers are sold at pressures well above that range, which is how so many brick walls end up etched.

The National Park Service reaches a similar conclusion. Its Preservation Brief 1 on cleaning historic masonry recommends starting with very low pressure, even a garden hose, and generally going no higher than 300 to 400 psi. It warns that "power washing" at too high a pressure is very abrasive and can etch soft stone and some types of brick. The brief notes its guidance applies to all masonry buildings, not just historic ones.

What Happens When Brick Is Cleaned Too Aggressively

Loss of the brick face. Brick is a fired product, and its smooth outer surface acts as a protective skin. The BIA notes that aggressive cleaning can remove that outer surface, and NPS notes that roughened masonry holds dirt and is harder to clean in the future.
Eroded mortar joints. Mortar is softer than brick. NPS notes that mortar joints can make up as much as 20 percent of a brick wall's surface, so eroding them removes a lot of material and can let more water into the wall.
Visible lines and streaks. A narrow stream moved unevenly leaves stripes that do not wash out.
Water forced into the wall. Excess water can find its way through weak joints and around windows.
A surface that gets dirty faster. Roughened brick holds dirt and growth, making the next cleaning harder.

This is the same reason roofs and painted siding should be soft washed. Our guide on soft washing vs. pressure washing explains the difference, and can pressure washing damage your house? covers other surfaces at risk.

Brick Looking Green, Black, or Dingy?

PrimeSite cleans brick homes and commercial buildings across Summerville, Charleston, and the Tri-County area using low-pressure methods matched to the surface.

Call (843) 410-3603 Request a Free Quote

What Is Growing (or Forming) on Your Brick?

Identifying the problem first is one of the most important steps in both the BIA and NPS guidance. Different stains need different treatments.

What You See	Likely Cause	Typical Approach
Green or black film, worst on shaded walls	Algae, mildew, or moss from moisture and shade	Pre-wet, apply a cleaner suited to organic growth, low-pressure rinse
White, powdery deposits	Efflorescence: water-soluble salts carried to the surface by moisture	Dry brushing or a stiff fiber brush and water; fix the moisture source first
Orange or brown streaks	Rust from metal fixtures or iron in irrigation water	A targeted rust treatment, not more pressure
Gray, dingy overall look	General dirt, pollen, and pollution	Low-pressure wash, often with a mild detergent
Dark streaks below gutters or sills	Overflowing gutters or runoff	Clean the brick and fix the water source

Efflorescence deserves a special note. The BIA recommends identifying and correcting the source of water before trying to clean recurring efflorescence. Washing it off without fixing a leaking gutter or a sprinkler hitting the wall just means it comes back. For orange streaks, see PrimeSite's rust and stain removal service. Not sure whether the dark growth is algae or mold? Our algae, mold, and mildew identification guide can help.

How Brick Should Be Cleaned

Following BIA and NPS guidance, a proper brick cleaning generally looks like this:

Identify the brick and the stain. Sand-finished, coated, glazed, and older soft brick need gentler handling.
Test a small, inconspicuous area first and let it dry before judging the result.
Protect windows, doors, metal, and plants from cleaning solution.
Saturate the wall with water at very low pressure so the brick does not absorb the cleaner.
Apply the cleaning solution by brush or low-pressure sprayer and let the chemistry do the work. The BIA says to keep application pressure at 50 psi or less.
Do not let the solution dry on the brick.
Rinse thoroughly at low pressure with a wide fan tip held back from the surface.
Manage runoff so cleaning solution does not go into storm drains or damage landscaping.

Products and Tools to Avoid on Brick

Muriatic (hydrochloric) acid. The BIA says not to use unbuffered muriatic or hydrofluoric acid. NPS warns muriatic acid can dissolve lime-based mortar, damage brick, and leave chloride deposits.
Wire brushes. They scratch the surface and can leave metal particles that rust and stain.
Sandblasting and other abrasive blasting. Both the BIA and NPS advise against it for general brick cleaning.
Zero-degree or turbo nozzles. These concentrate pressure into a tiny point and cut into masonry.
Cleaning in freezing weather. Both sources advise against water cleaning when freezing temperatures are expected. That is rare in the Lowcountry, but worth knowing for the occasional cold snap.

Older and Historic Brick Needs Extra Care

Charleston and the surrounding Lowcountry are full of older brick homes, churches, and commercial buildings. The National Park Service points out that soft, incompletely fired brick from the 18th and early 19th centuries can be especially vulnerable, and that lime mortar joints are easily eroded by aggressive cleaning. For buildings with historic significance, both the BIA and the National Park Service recommend involving a restoration specialist to choose the cleaning method.

Older homes and buildings also raise another question: paint. If brick trim, sills, or nearby woodwork on a pre-1978 building has been painted, lead-safe practices matter. PrimeSite is an EPA Lead-Safe Certified Firm (NAT-F339054-1). Read more in our guide to lead-safe pressure washing for older Charleston homes.

Brick Homes vs. Brick Commercial Buildings

On a home, brick is usually mixed with painted trim, vinyl or fiber cement siding, and windows, so the crew has to switch methods as it moves around the house. PrimeSite's house washing service uses soft washing for these mixed exteriors. On commercial buildings, the scale is larger and the work often happens around business hours and foot traffic. See PrimeSite's commercial building washing. Brick pavers and walkways are covered under driveway and concrete cleaning.

The Bottom Line

Brick can be cleaned safely, but not with the high-pressure blast most people picture when they hear "pressure washing." The guidance from the Brick Industry Association and the National Park Service is consistent: identify the stain, test first, use the gentlest method that works, keep pressure low, and let the right cleaning solution do the heavy lifting. Done that way, brick comes out clean and keeps the protective face it needs to last for decades.

Get Your Brick Cleaned the Right Way

PrimeSite Pressure Washing is locally owned in Summerville and cleans brick homes and buildings throughout Charleston, Mount Pleasant, North Charleston, Goose Creek, and Folly Beach.

Call (843) 410-3603 Request a Free Quote

Frequently Asked Questions

Can you pressure wash brick?

Yes, but only at low pressure with the right nozzle and cleaning solution. The Brick Industry Association says high pressure over 800 psi is not appropriate for brick, and recommends not exceeding 400 psi at the nozzle unless the brick manufacturer allows it.

What PSI is safe for cleaning brick?

BIA guidance uses under 100 psi for pre-wetting and 100 to 400 psi for rinsing, with a 25 to 50 degree fan tip held at least 12 inches from the surface. The National Park Service recommends starting below 100 psi and generally staying at or below 300 to 400 psi.

What is the white powder on my brick?

It is usually efflorescence, which forms when water carries soluble salts to the surface. Light deposits can often be dry brushed off, but the source of moisture should be fixed first or it will return.

Should I use muriatic acid to clean brick?

No. The Brick Industry Association advises against unbuffered muriatic acid, and the National Park Service warns it can dissolve lime-based mortar and damage brick.

How do you remove green algae from brick?

Pre-wet the wall, apply a cleaning solution suited to organic growth, let it work without drying, then rinse at low pressure. Improving drainage and reducing shade helps slow regrowth.