Pressure washing your driveway is an effective way to maintain the durability of concrete, enhance your home's curb appeal, and increase the asking price if you’re selling your house. Let's dive into the detailed steps to achieve a clean driveway.
1. Wear Safety Equipment
Safety gear is crucial when operating a pressure washer. Wear goggles to shield your eyes from flying debris, rubber gloves to protect against chemical burns and blisters, and a respirator if you're using potent chemicals. Wear sturdy, non-slip rubber boots for additional safety. You should also use earplugs to prevent hearing damage when operating a pressure washer.
2. Clear the Area
Clear the concrete before pressure washing. Begin by removing vehicles, bicycles, and other objects from your driveway. Sweep away loose debris like leaves, dirt, and small stones to prevent them from being scattered by the high-pressure water. If you own a leaf blower, you can use it to speed up the clearing process.
Use a weed wacker to cut back weeds and grass creeping onto your driveway. If your yard hasn’t been edged in a while, you may need a shovel to clear and bag the debris. To dispose of dirt and grass in San Antonio, you’ll need to drop it off at a private landfill.
3. Start Your Pressure Washer
Fully unravel your garden hose ahead of time to provide yourself with some slack and prevent it from getting tangled or kinked. Laying out your hose in a wide “S” formation is a great way to keep it organized. Connect one end of the hose to your home’s exterior water supply and the other end to your pressure washer.
If you’re using an electric pressure washer, you’ll need to plug it into an exterior wall outlet. The cord included with most pressure washers isn’t that long, so you’ll probably need an outdoor extension cable. Ensure water is running to the pressure washer before turning it on.
A gas pressure washer is pricier than an electric pressure washer but tends to be more reliable and last longer. Before using a gas pressure washer, make sure that it contains oil and that the gas has been topped up. Turn on the pressure washer, open the fuel line, and close the choke. Then, pull the rip cord to start the engine and open the choke to allow air into the carburetor.
Most consumer pressure washers include a built-in chemical reservoir, which you’ll fill with your concrete cleaner. This solution is injected downstream (after the pressure washer’s pump) into the water stream, allowing you to apply it to your driveway with the pressure washer’s spray wand.
4. Choose the Right Spray Nozzle
Pressure washers typically come with four common spray nozzles, each designed for different cleaning tasks. These nozzles are distinguished by the angle of the water spray they produce, affecting the intensity and spread of the water jet.
Here are the four standard pressure washing nozzles:
- Soaper (Black): The black nozzle is designed to apply soap and cleaning agents. It creates a wide spray pattern at low pressure, ideal for pre-soaking or applying detergents to surfaces prior to pressure washing. Attaching this nozzle to your spray wand will cause your cleaning chemical to dispense due to the low pressure.
- 40-Degree Nozzle (White): The white nozzle features the widest spray pattern, making it suitable for cleaning stairs, patios, and driveways. You should use this nozzle for general rinsing purposes as well. Start with your widest nozzle and resort to nozzles with a narrower angle as necessary.
- 15-Degree Nozzle (Yellow): The yellow nozzle offers a broader spray angle and is suitable for heavy-duty cleaning tasks. It's effective for stripping paint and removing stubborn grime and mildew.
- 0-Degree Nozzle (Red): The red nozzle produces a highly concentrated, narrow jet of water. It’s ideal for tackling tough stains and areas that are difficult to clean. However, its high intensity can damage soft surfaces, so it should be used with care.
5. Pre-Treat with Sodium Hypochlorite
Applying a concrete cleaning solution before pressure washing your driveway can help loosen tough stains and make pressure washing more effective. Before applying chemicals to your driveway, soak the grass and plants around the area with water, protecting them from the chemicals.
Attach the black nozzle to your pressure washing wand to dispense your cleaning solution. Some pressure washers may require you to adjust a dial to control the amount of chemical injected into the water stream. Refer to your pressure washer’s user manual for specific instructions about this step.
If you see a white and frothy chemical reaction taking place within 15 seconds of application, you’ve applied a sufficient amount of cleaning solution. Thoroughly soak your driveway in the cleaning solution and allow it to dwell for 15 minutes. During this time, spray your greenery with water again to prevent chemical damage.
6. Pressure Wash the Driveway
Begin by edging the perimeter of the driveway with your 45-degree nozzle. Use the pressure washer to clean along the edges and corners where the driveway meets the grass or landscaping. This helps prevent overspray onto adjacent areas and ensures crisp, detailed edges.
For the main area of the driveway, use a surface cleaner attachment. This tool, resembling a large disc, has spinning nozzles underneath and provides a consistent, even clean. It covers a larger area than a standard spray nozzle, making cleaning quicker and reducing the likelihood of striping. When shopping for a surface cleaner, match the PSI rating of the surface cleaner to your pressure washer.
Push the surface cleaner from one end of the driveway to the other, slightly overlapping each pass for a thorough clean. Move slowly and at a steady pace to avoid cleaning one area too much; this can lead to the formation of rings.
Use the 15-degree or 0-degree spray nozzle to clean stubborn stains or missed spots. Adjust the distance and angle of the nozzle to effectively clean these tough areas without damaging the concrete.
7. Spot Treat Oil Stains
Before you pressure wash your driveway, you should start by spot-treating oil stains. Pressure washing an oil stain without using a degreaser will be minimally effective. Degreasers are formulated to break down and lift oil off concrete surfaces.
Dilute the degreaser as indicated on the container and apply it to the stained surface. Most commercial degreasers should applied at a ratio of 4 parts water to 1 part degreaser. Heavier oil stains may require you to apply at a water to degreaser ratio of 1:1.
Then, scrub the area with a deck brush. You should repeat this process multiple times for the best results. Depending on the age of an oil stain, you may not be able to remove it entirely, so aim for improvement rather than perfection.
After spot-treating your driveway, rinse away residual degreaser using your pressure washer’s 45-degree nozzle.
Oil stains are removed more effectively using hot water, but most hot water pressure washers cost thousands of dollars. If you're dealing with heavy oil stains, you may want to consider hiring a pressure washing service near you.
8. Remove Rust Stains
Rust stains reveal themselves when you remove built-up mold and mildew on your concrete. You can remove rust using an oxalic acid treatment. Oxalic acid is effective in dissolving rust (iron oxide) from concrete. It’s typically sold in powder form and requires you to mix it with water.
Mix 16 ounces of oxalic acid per 1 gallon of water in a garden sprayer. Use a paint mixer drill bit to blend the solution for best results. Spray the oxalic acid onto the rust stain and allow the chemical reaction to do the work. The rust stain should disappear in 1-2 minutes. Apply a second coat if the first treatment doesn’t completely remove it. Oxalic acid is an extremely potent chemical, so use a respirator.
Once the rust is removed, rinse the surface and surrounding greenery with water. Oxalic acid can damage plants, so this is a critical step.
9. Rinse with Water
After agitating dirt, grime, and stains, rinsing helps to remove the loosened debris and chemicals, leaving the surface clean.. Using a wide fan nozzle with moderate pressure ensures that the contaminants are flushed away without damaging the surface of the driveway. It's important to start rinsing from the highest point and work downwards, guiding the runoff towards drainage areas to prevent streaks and ensure an even, thorough clean. Proper rinsing not only enhances the appearance but also prevents the buildup of cleaning agents, which could cause discoloration or residue over time.
10. Post-Treat with Sodium Hypochlorite
After pressure washing, you may notice some light striping. Apply another coat of concrete cleaner and let it sit to remove these stripes. Do not rinse off the cleaning agent. It will continue to brighten the surface as it dries. Stay off the surface until it's dry, ideally waiting 24 hours before driving over it. The following "After" image was taken before post-treating the concrete, so you can still see some light cleaning stripes.
Can You Soft Wash a Driveway?
Pressure washing a house requires a different approach, and in some cases an alternative cleaning method called soft washing. Soft washing uses low pressure water mixed with sodium hypochlorite to perform the entire cleaning process. You can soft wash a driveway, but it often requires multiple chemical applications. Soft washing is the recommended cleaning method if a driveway is less than five years old, or if the cream layer hasn't worn down yet.
Regular pressure washing maintenance keeps your driveway looking pristine and extends its lifespan. Guardian Pressure Washing provides a professional power washing service to San Antonio residents. Get a free estimate online or call us at (210) 560-5966 for more details.
