Concrete is a durable, low-maintenance material both indoors and out, and it's fairly resistant to staining. But it's also porous, which means it gradually soaks up dirt over time — and once mildew takes hold, it's both unattractive and a potential health concern. Here's how to clean it the right way.
What To Use
A pressure washer is the most effective tool for the job — it makes quick work of dirt, mildew, and grime, and it isn't difficult to use well once you know the right pressure and cleaning solution to pair with it.
For cleaning solutions, bleach, ammonia, or a commercial concrete cleaner all work depending on the situation. For a particularly tough stain, a mixture of hydrogen peroxide left to sit for about a day, then gently scraped off, can do the trick. Trisodium phosphate mixed with water is another option for general dirt and staining. Muriatic acid can tackle the toughest stains, like dried grout or rust, but it's best reserved for exterior concrete only.
Stamped or polished concrete needs a gentler touch — a mop and a bucket of water with a mild cleaner is usually the safer route, since bleach or ammonia's higher acidity can damage those finishes.
Steps For Cleaning Concrete With A Pressure Washer
Step 1: Clear The Space
Remove anything that might get in the way — vehicles, toys, outdoor furniture, or equipment.
Step 2: Prep Your Equipment
Attach the hose and nozzle, then give the concrete an initial pass to clear away loose debris like grass, pebbles, or dirt.
Step 3: Apply Detergent
Switch to a soaping nozzle so the detergent is applied evenly rather than blasted on. Check your equipment's manual for guidance on the right cleaner for your surface.
Step 4: Let It Sit
Give the detergent at least five minutes to work before rinsing — that dwell time is what actually breaks down stains and grime.
Step 5: Rinse It Off
A surface cleaner attachment covers a wide area efficiently and reduces the risk of accidentally damaging the concrete yourself. A rotary nozzle is another good option for stubborn spots. Once you're satisfied, give the whole area a final, thorough rinse.
After You're Done
Once your concrete driveway or patio is clean, applying a sealant helps protect it from future staining — a paint roller makes quick work of it, just be sure to cover the edges. Resealing every two or three years, paired with regular pressure washing, keeps concrete looking good for the long haul.