Your patio is where you grill, entertain, and relax, so it’s easy to notice when it starts looking tired. Green algae, black mildew, weeds in the joints, and ground-in dirt can turn a nice outdoor space into something you’d rather avoid.

Pressure washing a patio can bring it back, but patios are built from many different materials, and each reacts differently to pressure. This guide covers how to clean each one, what pressure to use, and how to avoid the mistakes that cause the most damage.

Why Patio Cleaning Matters

A dirty patio isn’t just unattractive:

• Slip hazard: Algae and mildew make surfaces slick, especially when wet.
• Surface wear: Moss and organic buildup hold moisture against the material and can speed up deterioration.
• Weed growth: Dirt in the joints gives weeds a place to root and spread.
• Enjoyment and value: A clean outdoor space is easier to use and makes a strong impression on guests and buyers.

Know Your Patio Material First

Poured concrete is the most durable and handles higher pressure well, though it can still be etched if you use too narrow a nozzle or hold it too close.

Concrete pavers are tough but vulnerable at the joints. High pressure can blast out the sand between pavers, which loosens them and invites weeds.

Brick cleans up well, but old or soft brick and aging mortar can erode under strong pressure.

Natural stone such as flagstone, travertine, slate, and limestone is more delicate. Many natural stones are porous and can be scarred or stained by harsh pressure or strong chemicals.

Stamped or sealed concrete needs care, because aggressive washing can strip the sealer and dull the finish.

PSI and Nozzle Guide for Patios

As a general guide:

• Poured concrete: roughly 2,500 to 3,000 PSI
• Concrete pavers and brick: roughly 1,500 to 2,000 PSI
• Natural stone and older or sealed surfaces: roughly 1,000 to 1,500 PSI, or soft washing

Use a 25° or 40° nozzle for most patio work, and avoid narrow nozzles that can etch surfaces and leave lines. A surface cleaner attachment is the best tool for flat patios, because it keeps the spray at an even distance and helps prevent the striped look you can get from a bare wand.

What You Need

• A pressure washer suited to your patio material
• A surface cleaner attachment, plus 25° and 40° nozzles
• A patio or concrete cleaner (an oxygen-based cleaner is a gentler choice for stone)
• A stiff nylon brush for stubborn spots
• Polymeric sand if you have pavers
• Safety glasses, closed-toe shoes, and gloves

Step-by-Step: How to Pressure Wash a Patio

1. Clear the patio. Move furniture, grills, and planters. Sweep away leaves and loose debris.
2. Remove weeds. Pull weeds from the joints before washing so they don’t scatter dirt and seeds.
3. Pre-wet the surface and nearby plants. This dilutes cleaners and helps protect landscaping.
4. Apply a cleaner. Use a cleaner suited to your surface and let it dwell for the time on the label, without letting it dry. This does much of the work on algae and mildew.
5. Scrub tough spots. A stiff nylon brush helps loosen stains and heavy growth.
6. Wash in even passes. Use a surface cleaner or a wide nozzle, keep a steady distance, and overlap each pass slightly. Work from the high side to the low side so dirty water flows away.
7. Be gentle at the joints. With pavers and brick, avoid aiming pressure directly into the joints.
8. Rinse thoroughly. Wash off all cleaner and loosened dirt before it dries.
9. Let it dry fully. This is important before re-sanding or sealing.

How to Handle Common Patio Problems

Green algae and black mildew. A patio cleaner left to dwell works better than pressure alone. Soft washing is often a good option on delicate stone.

Moss. It grows in shaded, damp spots and in joints. Treat it with a cleaner, loosen it, and rinse it away.

Rust stains. These come from metal furniture, planters, or sprinkler water. Use a product made for rust removal, and avoid bleach, which can set the stain.

Oil and grease. Apply a degreaser, let it sit, scrub, and wash again. Older stains may need more than one attempt.

White chalky deposits (efflorescence). These are mineral salts that rise to the surface of concrete, brick, and pavers. They are removed with a cleaner made for efflorescence, not by pressure alone, and they can come back if moisture stays an issue.

Re-Sanding Pavers After Washing

If you have pavers, plan to refill the joints after cleaning. Sweep fresh polymeric sand into the dry joints, compact it, brush off the excess, and lightly mist it according to the product directions. The sand hardens, holds the pavers in place, and helps block weeds and ants. Skipping this step is one of the most common reasons paver patios look worse a few months after a wash.

Common Patio Pressure Washing Mistakes

• Using too much pressure. It can etch concrete, erode brick, and gouge soft stone.
• Blasting the joints. It removes the sand that locks pavers together.
• Skipping the cleaner. Water alone rarely kills algae and mildew at the root.
• Washing in direct sun. Cleaner can dry before you rinse and leave streaks.
• Using harsh chemicals on natural stone. Acids and strong bleach can etch or discolor it.
• Sealing too soon. Sealing a damp patio traps moisture and can cause a cloudy finish.

Should You Seal Your Patio?

Sealing is optional but worthwhile for many patios. A good sealer helps repel water and stains, enhances color, and makes the next cleaning easier. For pavers, sealing also helps stabilize the joint sand. Apply it only when the surface is completely dry, usually after a day or two, and follow the manufacturer’s directions. Most sealers need reapplying every few years.

Don’t Forget Walkways and Sidewalks

The same principles apply to walkways, steps, and sidewalks. They collect algae, tire marks, and grime, and slippery walkways are a safety concern. Use a surface cleaner where possible, work in sections, and take extra care near edges and expansion joints. If you share a sidewalk with the public, check local rules about runoff and chemicals before you start.

How Much Does Patio Pressure Washing Cost?

Prices depend on the patio’s size, material, condition, and any extra work like re-sanding or sealing. Many homeowners pay somewhere in the range of $100 to $300 or more for a typical patio, with large patios, delicate stone, and heavy staining costing more. Renting equipment can seem cheaper, but add cleaners, sand, sealer, and the risk of damaging the surface.

When to Hire a Professional

DIY works for small, sturdy concrete patios. Consider a professional when:

• Your patio is made of pavers, natural stone, or sealed material
• Algae, moss, or stains are heavy or keep coming back
• You want pavers re-sanded and sealed properly
• You don’t own a surface cleaner or the right equipment
• You’d rather avoid the risk of damaging an expensive surface

A trained crew knows how to match pressure, cleaners, and methods to each material. If you’d like it done right the first time, a professional patio and walkway cleaning service can restore your outdoor space and give you a free quote before starting.

Final Thoughts

Pressure washing a patio is a satisfying project, but the right approach depends on what the patio is made of. Know your material, use a wide nozzle or surface cleaner, treat algae with the right cleaner, protect the joints, and let everything dry before sealing. Done properly, your patio will look great and stay safer and cleaner for much longer.