What do you pretreat concrete before pressure washing?

When it comes to pressure washing concrete, pretreating is an important step that shouldn’t be skipped. Properly pretreating concrete before pressure washing helps lift stubborn stains, prevent surface damage, and allows for much better cleaning results. Here’s what you need to know about pretreating concrete prior to pressure washing.

Why Pretreat Concrete Before Pressure Washing?

Pretreating concrete before pressure washing serves a few key purposes:

• Helps lift stubborn stains and debris – Pretreatment solutions contain chemicals that work to break down and loosen caked-on dirt, oil, grease, food stains, chewing gum, and other debris. This makes them much easier to remove with pressure washing.
• Avoids surface damage – Pressure washing without pretreating can damage the concrete surface by etching it. Pretreating helps prevent this.
• Improves cleaning results – When you pre-soften stains and contaminants, they are much more effectively removed by pressure washing rather than leaving them stuck on the concrete.
• Saves time and effort – The pretreatment does a lot of the hard work in breaking down stains so the pressure washer doesn’t have to. This makes the job faster and easier.

The bottom line is that taking the time to pretreat your concrete will mean a deeper, more complete clean when you pressure wash it. The pretreating products help loosen the stubborn dirt and grime so the pressure washer can do its job more effectively.

How to Choose a Concrete Pretreatment Product

There are a few different types of pretreatment products for concrete:

• Concrete degreasers – Designed to break down oil, grease, fat, and food stains.
• Concrete cleaners – Contain detergents and chemicals to help dissolve general dirt, grime, tire marks, etc.
• Concrete brighteners – Used to prep heavily stained or weathered concrete for pressure washing and remove ingrained rust stains.

When choosing a pretreatment product, consider the type of stains or contaminants you need to remove. A degreaser is ideal for oil/grease stains while a brightener works well for weathered concrete or rust stains. For general dirt and grime, a heavy-duty concrete cleaner is a good all-purpose option.

You’ll also want an alkaline-based pretreatment since alkaline is more effective at breaking down stains than acidic products which can potentially damage concrete. A pH of 11-12 is ideal.

Using the right product for your concrete ensures the pretreating stage effectively prepares the surface for pressure washing.

How to Apply Concrete Pretreatment

Here is a simple step-by-step process for pretreating concrete before pressure washing:

1. Sweep the concrete thoroughly to remove loose debris and dirt. This prevent clogging.
2. Use a garden hose to lightly wet down the surface. Don’t soak it, just dampen it.
3. Apply your chosen pretreatment product as directed on the label. Most products recommend diluting the solution with water first. Apply it evenly across the concrete surface using a pump sprayer.
4. Let the pretreatment sit and soak for 10-15 minutes. This gives the chemicals time to work.
5. For improved results, use a stiff bristle broom or brush to gently scrub the pretreatment over the concrete. This helps it fully penetrate.
6. Rinse thoroughly with a hose. Powerful stream hoses work best.
7. Allow the concrete to fully dry before pressure washing. This may take 24-48 hours if there was heavy pretreatment used.

Following these simple steps ensures you get the most out of the concrete pretreatment before bringing in the pressure washer. Letting the chemicals sit for 10+ minutes and scrubbing it in is key for effective stain removal.

Pretreatment Tips

Here are some useful tips to get the most out of pretreating concrete:

• Always read and follow the product labels for correct dilution ratios and application instructions.
• Wear gloves, eye protection, and other PPE when handling pretreatment chemicals.
• Apply an even coating across the entire surface to be cleaned.
• Pretreat on a warm, sunny day when the concrete is dry. Avoid windy conditions.
• Use a broom with stiff bristles to really work the pretreatment into the pores.
• Rinse thoroughly after letting the product sit for 10-15 minutes.
• Allow concrete to dry fully before pressure washing. 48 hours is ideal.
• Reapply pretreatment to any severely stained areas before pressure washing.

Taking the time to properly pretreat concrete before bringing in the pressure washer leads to far superior cleaning results. It just takes a little bit of work upfront to prep the surface.

What Pretreatment Products to Use

Some of the top-rated and most effective concrete pretreatment products include:

Concrete Degreasers

• Simple Green Concrete Cleaner
• Krud Kutter Original Concentrate Degreaser
• Zep Purple Heavy Duty Cleaner and Degreaser
• Spray-N-Wash Max Concrete & Driveway Degreaser

Concrete Brighteners

• Defy Concrete Brightener Cleaner
• SureClean Concrete Brightener
• CLR Calcium, Lime, and Rust Remover
• Wet & Forget Moss, Mold, Mildew & Algae Stain Remover

All-Purpose Concrete Cleaners

• Concrete Cleaner and Etch from Homax Products
• CHI Over and Done Concrete Cleaner
• Simple Green Concrete and Driveway Cleaner
• 30 Seconds Outdoor Cleaner Concentrate

Be sure to match the right product to the specific stains on your concrete. Test on a small inconspicuous area first before full application. Always follow label instructions closely.

DIY Homemade Concrete Pretreatment Recipes

You can also make effective concrete pretreatment solutions at home using common household ingredients. Here are a few options:

Baking Soda Degreaser

• 1 cup baking soda
• 1/4 cup liquid dish soap
• 2 gallons hot water

Mix ingredients in a bucket and apply to oil-stained concrete. Let sit 15 minutes before rinsing. Scrub with a broom.

Vinegar Brightener

• 2 parts white vinegar
• 1 part water

Combine in a spray bottle and spray over rust stains or weathered concrete. Let sit 30 minutes before rinsing thoroughly. Reapply as needed.

All-Purpose Cleaner

• 1/2 cup TSP substitute (e.g. Soilax)
• 1/4 cup automatic dishwasher detergent
• 2 gallons hot water

Mix together in a bucket and apply to dirty or stained concrete with a mop or brush. Rinse thoroughly after 15 minutes.

These homemade cleaners offer an effective and affordable alternative to commercial products. Adjust recipes as needed to suit your concrete cleaning needs.

How to Pressure Wash Concrete After Pretreating

Once your concrete has been pretreated and allowed to fully dry, follow these tips for pressure washing:

• Use a pressure washer with at least 3000 PSI. Electric pressure washers around 1.5-2 GPM are suitable for residential use.
• Choose a fan tip nozzle between 15-25 degrees. The spray should be angled, not direct.
• Keep the nozzle 6-12 inches from the concrete surface.
• Apply the spray evenly in overlapping paths.
• For oil stains, spray at a 45 degree angle near the stain to lift it.
• Take care around cracked or pitted areas. Avoid spraying directly into cracks which can etch the surface.
• Rinse thoroughly, going over the concrete 2-3 times to remove all pretreatment residue.
• Let concrete dry fully before sealing, painting or continued use.

Pressure washing at the proper distance and angle consistently across the concrete will provide the best final rinse. Take care around landscaping, plants, siding or cars you don’t want accidentally sprayed.

Troubleshooting Pretreatment Issues

If your concrete pretreating isn’t going as well as planned, here are some troubleshooting tips:

Issue	Solution
Pretreatment not effective on stains	Ensure you used the right product for the stain type. Let sit for 15-20 minutes before rinsing. Use a stiff broom to scrub it in for heavy stains. May need a second application if the stain is old.
Concrete turning white	Rinse thoroughly after pretreating. Avoid acidic-based pretreatments. Only apply in recommended dilutions.
Pressure washer not removing pretreated stains	Let concrete dry fully after pretreating before pressure washing. Heat water for gas pressure washer for highest cleaning action. Move nozzle closer for stubborn stains and fan spray at an angle.
Nozzle clogging frequently	Make sure concrete is swept before pretreating. Use a wider angle nozzle. Don’t hold nozzle too close to the surface.

With a little troubleshooting, you can get great pretreating results. Test products and techniques in an inconspicuous area first.

Conclusion

Preparing concrete surfaces with the proper pretreatment before pressure washing makes a big difference in the final clean. Taking the time to apply a degreaser, brightener or heavy-duty cleaner before rinsing allows the chemicals to break down stubborn stains so they can be completely removed. Matching the right pretreatment product to your type of concrete staining and following label dilutions and directions will ensure optimal cleaning results.