How to Clean a Brick Patio in Houston (And Why It's Harder Than It Looks)

If you have a brick patio in the Houston area, you already know the drill. One season it looks great. The next, it's covered in a dark film of algae, mold, or that stubborn orange-brown stain that seems to appear out of nowhere. You're not imagining it — brick is one of the most porous outdoor surfaces there is, and our Gulf Coast climate is basically a perfect storm for everything that makes it look terrible.

This guide walks through what's actually happening to your brick, what it takes to clean it properly, and when it makes sense to handle it yourself versus calling in a professional.

The combination of high humidity, warm temperatures, and frequent rain creates ideal conditions for biological growth. Algae, mold, mildew, and lichen all thrive in these conditions — and brick's rough, porous surface gives them plenty of places to grip and spread.

In neighborhoods like Sugar Land, Missouri City, and Pecan Grove, where mature trees provide shade over patios and outdoor living spaces, you'll often see green or black discoloration develop within a single season. Shaded areas stay damp longer, which accelerates growth significantly.

There's also the issue of efflorescence — those white, chalky deposits that appear on brick surfaces. This happens when water moves through the brick and carries dissolved salts to the surface. It's harmless structurally, but it looks rough and is notoriously stubborn to remove without the right approach.

Before you grab a pressure washer, it helps to identify what you're cleaning:

• Green or black film — algae or mold. Common on shaded patios and north-facing surfaces.
• White chalky deposits — efflorescence. Requires a mild acid treatment, not just water pressure.
• Orange or rust stains — often from iron in the soil or nearby metal fixtures. Needs a specialized rust remover.
• General grime and dirt — the everyday buildup from foot traffic, pollen, and weather.

Each of these responds differently to cleaning methods, which is why a one-size-fits-all approach often leaves homeowners frustrated.

Brick can handle pressure washing, but it requires more care than concrete. Here's what matters:

Use the right pressure. Too much pressure — anything above 1,500–2,000 PSI on older or softer brick — can erode the mortar joints and damage the brick face itself. This is one of the most common DIY mistakes. The goal is to clean the surface, not blast it.

Keep the nozzle moving. Holding the spray in one spot concentrates pressure and can etch the surface. Use a wide-angle tip (25–40 degrees) and keep the wand moving in consistent strokes.

Pre-treat biological growth. For algae and mold, a pre-treatment with an appropriate cleaning solution — applied and allowed to dwell before rinsing — does most of the work. Trying to remove heavy biological growth with water pressure alone usually just spreads it around.

Rinse thoroughly. Any cleaning solution left on brick can cause discoloration or accelerate efflorescence. A thorough rinse is just as important as the cleaning pass.

For a small patio with light surface dirt and no significant biological growth, a homeowner with a decent consumer-grade pressure washer can get reasonable results. It takes time, the right nozzle, and some patience.

Where DIY tends to fall short:

• Heavy algae or mold that's been building up for multiple seasons
• Efflorescence that keeps coming back (often a sign of a drainage or moisture issue)
• Large patios or outdoor living areas where consistency matters
• Older brick or soft mortar that needs a gentler touch

Professional equipment runs at higher flow rates (not just higher pressure), which means faster, more thorough rinsing and better results on stubborn staining. A professional also knows how to adjust technique for different brick types — something that's easy to get wrong without experience.

If your patio in Katy, Richmond, Rosenberg, or Brookshire hasn't been cleaned in a few years, or if you're seeing significant biological growth, it's usually worth having a professional assess it before you risk damaging the surface.

Sealing is optional, but it can make a real difference in how long your patio stays clean. A quality penetrating sealer reduces the porosity of the brick, making it harder for algae and mold to take hold and easier to rinse off surface dirt.

In the Houston climate, a sealed brick patio typically stays cleaner longer between professional cleanings — which saves money over time. If you're going to seal, make sure the brick is completely dry (usually 24–48 hours after cleaning) and use a product rated for exterior masonry.

If your brick patio has seen better days, our residential pressure washing service covers patios, walkways, driveways, and other outdoor surfaces throughout the greater Houston area. We work in Richmond, Sugar Land, Katy, Rosenberg, Missouri City, Pecan Grove, Fulshear, Brookshire, and surrounding communities.

We'd love to earn your trust — and your review. If you've had work done with us and haven't had a chance to share your experience, it means a lot to a small local business. Leave us a Google review here — it takes less than a minute and helps other Houston-area homeowners find reliable service.