How to Clean Pavers: Remove Moss & Weeds, Kill Algae, Control Pests, & Remove Oil from Any Hardscape

Let’s take a look at a few different ways to clean your pavers.

Spot Cleaning

It’s pretty common for some weeds to sprout up in the sand joints of your paving stones. The easiest way to tackle the problem is to spray them with a weed killer and then remove them once they’re dead. But if there’s only a handful of them, it’s pretty simple to manually go around and pluck them out. If you want to reduce the chance of weeds returning later on, you can look into an antifungal sealer or something similar to reduce your weeds and help with maintenance.

Moss growing in your sand joints is another common problem. If you just have a little bit of moss, the easiest and fastest way to get results involves mechanically scraping the moss away with a screwdriver or a scraping tool. Just make sure that when you’re scraping it away, you try not to scratch the top of the paving stone and just focus on the sand joints. 

If you have a decent amount of moss on your paving stones, mix some 50/50 bleach and water to kill that moss a day prior to rinsing it off. If you have a high-pressure garden hose, you’ll more than likely get a lot of it off, making it much easier. But if your entire paving stone project is completely covered and moss is growing in those sand joints, go further down this article to where we share about large surface cleaning. The fastest, most efficient way to clean off a bunch of moss is by using a surface washer attachment attached to a pressure washer.

Under a paving stone driveway, you can count on some occasional oil stains from a leak in a vehicle; or maybe near your backyard barbecue you’ll see grease stains from food. The easiest way to remove oil stains is by using SEK Surebond’s Oil Extractor. It’s a cool product and super easy to use. All you have to do is apply it to the oil stain area and let it work for about 10 minutes without drying out. If it starts to, just reapply the product, and after that 10 minute time frame you can rinse it away and repeat the process until the oil stain is completely lifted. It’s super easy and works better if you scrub it, but you should be left with a really good result after using it once or maybe a few times.

Acid Washing

Efflorescence is something you might want to do spot cleaning for on your paving stones. Efflorescence is usually a white or sometimes blue, hazy substance that is naturally derived from the cement in your paving stone. It emerges either through excessive moisture or improper curing of the product. The best way to remove efflorescence is to let it be removed naturally through lots of rainfall over periods of time. If you live in a climate where you don’t have rainfall, or your patio or walkway is covered, then one option is to wash those paving stones with heavily diluted muriatic acid. In our example we used 19 parts water to one part acid. We put it into a watering can and dumped it onto the dry paver surface or small area.

If you’re doing some small spot cleaning, you’ll want to let it sit for 30 seconds to one minute and then rinse it off with water. You can repeat that process until the efflorescence is all the way gone or it looks better. What you’re basically doing is deteriorating the surface of that stone to make it look a couple years old, or weathered, but it should look better than the white hazy efflorescence that you would otherwise have. 

Make sure that if you use muriatic acid, you also use proper PPE, including chemical resistant gloves, safety glasses, and a vapor respirator—specifically an N100 vapor respirator—because this is a harsh chemical. Try to avoid metal finishings like galvanizing or powder coating because it can promote rust.

Large Surface Cleaning

If you have so much moss in your sand joints that it’s basically covering your whole project, you’ll want to consider using a pressure washer. With a pressure washer, the main thing to keep in mind is that you don’t want to exceed about 2000 PSI, especially if you have really new or fresh paving stones. You can certainly exceed that, but be mindful that you may remove some larger aggregate from those paving stones just because it’s a lot of pressure. 

You can do the job with a wand, it would just take a lot of time to be thorough and consistent. We like to use a surface washer attachment because it uses two heads that distribute the pressure. It’s close to the ground and  super even. If you move at a nice, slow and steady pace, you’ll be very efficient in cleaning all the moss and surface lichen off your paving stones. You’ll still need a wand to go back and hit your edges, but you’ll most likely be left with a really clean project.

After you finish surface washing your entire area, you can take the wand attachment and spray your edges anywhere the surface cleaner couldn’t reach. Once everything finally dries out, you can spot check everything to make sure all the moss is gone. Then you can top off your joints with sand. You won’t need a lot of joint sand because you washed some out and put some back in through the process, but you want to top off your joints for optimal structure and aesthetics.