Why Pretreating and Post-Treating Are Essential for Professional Pressure Washing Results
Pressure washing is a powerful cleaning method that can restore the appearance of your home’s exterior, driveways, sidewalks, and other surfaces. However, to achieve the best results—especially on stubborn stains, grime, or biological growth like mold and mildew—it’s crucial to understand the importance of pretreating and post-treating. These steps are not just optional; they are essential for ensuring a thorough, long-lasting clean. In this blog post, we’ll explore why pretreating and post-treating are vital in the pressure washing process and how they can significantly enhance the effectiveness of your cleaning efforts.
Why Pretreat Before Pressure Washing?
Pretreating involves applying a chemical solution to the surface before pressure washing. This step is vital for several reasons:
Breaks Down Tough Stains:
Concrete, wood, and other porous surfaces can absorb dirt, oil, grease, and other substances deeply. Pretreating helps loosen and emulsify these contaminants, making them easier to remove during pressure washing. Without pretreatment, high-pressure water might only remove superficial dirt, leaving behind embedded stains.Saves Time and Effort:
Pretreating reduces the amount of time and pressure needed to clean a surface. By breaking down grime beforehand, the pressure washing process becomes more efficient, often cutting cleaning time by half or more.Protects the Surface:
Using the right pretreatment can help protect delicate surfaces from damage caused by high-pressure water. For example, on wood decks, pretreating can soften dirt and mildew without stripping the wood’s protective sealant.
For concrete driveways, a common pretreatment solution includes a mix of sodium hypochlorite (SH, commonly found in liquid pool chlorine) and dish soap. A recommended SH concentration is 2-4% (equivalent to diluting 12.5% pool chlorine to about 1 part chlorine to 3-5 parts water) mixed with 2 ounces of Dawn dish soap in a 2-gallon sprayer. This solution effectively kills mold, mildew, and algae while breaking down grease and oil stains. After applying the pretreatment, allow it to dwell for 5-10 minutes to maximize its effectiveness.
The Pressure Washing Process
Once the pretreatment has had time to work, you can begin pressure washing. Start from the bottom of the surface and work your way up to ensure the cleaning solution remains on the surface as long as possible. Using a surface cleaner attachment can provide a more uniform clean and help prevent striping. For best results, use a pressure washer with sufficient gallons per minute (GPM)—ideally 5.5 GPM or higher for commercial-grade machines.
Why Post-Treat After Pressure Washing?
Post-treating involves applying another chemical solution after pressure washing. This step is often overlooked but is crucial for several reasons:
Removes Residual Stains:
Even after pressure washing, some stains or contaminants might remain. Post-treating helps break down and remove these lingering issues, ensuring a truly clean surface.Kills Bacteria and Mold:
A post-treatment solution can eliminate any remaining bacteria, mold spores, or algae, preventing quick re-growth. This is especially important for surfaces like driveways and sidewalks, which are prone to biological growth.Enhances Longevity:
By killing off any remaining contaminants, post-treating helps keep your cleaned surfaces looking better for longer. It also reduces the likelihood of streaking or discoloration.
For driveways, a post-treatment solution typically uses a similar SH concentration as the pretreatment (2-4% SH, or 1 part 12.5% pool chlorine to 3-5 parts water) with dish soap to reduce striping and ensure a thorough clean. For particularly stubborn stains, a stronger mix of 5-6% SH (approximately 1 part 12.5% pool chlorine to 1-2 parts water) may be used for targeted treatment, applied sparingly to avoid surface damage.
Pretreating and Post-Treating for Concrete Driveways
Concrete driveways are particularly prone to stains from oil, grease, tire marks, and biological growth like mold and mildew. Pretreating with a solution of sodium hypochlorite and dish soap can effectively break down these substances. After pressure washing, applying a post-treatment solution helps kill any remaining bacteria and prevents quick re-soiling, ensuring your driveway stays cleaner for longer.
Step-by-Step Guide for Driveway Cleaning:
Pre-Treatment:
Remove debris (e.g., rocks, mulch) from the driveway.
Pre-wet surrounding grass with a garden hose to minimize chemical absorption.
Mix a pretreatment solution with 2-4% sodium hypochlorite (e.g., 0.5-0.6 gallons of 12.5% liquid pool chlorine diluted with water to fill a 2-gallon sprayer, plus 2 ounces of Dawn dish soap).
Apply the solution evenly across the driveway and let it dwell for 5-10 minutes.
Pressure Washing:
Use a surface cleaner attachment and start washing from the bottom, moving upward to maintain the cleaning solution’s effectiveness.
Post-Treatment:
Apply a post-treatment solution with 2-4% sodium hypochlorite (same dilution as pretreatment) to reduce striping and kill remaining bacteria.
For stubborn stains, use a targeted 5-6% SH solution (e.g., 1 part 12.5% pool chlorine to 1-2 parts water) sparingly.
Safety Note:
Always wear safety goggles and gloves when handling chemicals and operating a pressure washer. Keep children and pets away from the work area. Sodium hypochlorite is corrosive; avoid overuse or prolonged exposure to surfaces and vegetation.
Conclusion
Pretreating and post-treating are integral parts of the pressure washing process that can significantly improve the quality of your cleaning results. By using the right sodium hypochlorite concentrations, you ensure that your surfaces are not just clean but also protected and maintained for longer periods. At Record Pressure Washing, LLC, we incorporate these best practices into every job to deliver the highest quality service to our customers. Whether you’re tackling a driveway, sidewalk, or deck, understanding and implementing pretreating and post-treating with proper SH percentages will make all the difference in achieving professional-grade results.
Additional Tips
Safety First: Always wear protective gear like gloves and goggles when handling chemicals and operating pressure washers.
Test First: Before applying any chemicals, test a small area to ensure they are suitable for the surface.
Hire Professionals: For the best results, consider hiring a service like Record Pressure Washing, LLC, where our experts handle all the details for you.
FAQs
What chemicals should I use for pretreating concrete?
A common pretreatment for concrete includes a 2-4% sodium hypochlorite solution (e.g., 0.5-0.6 gallons of 12.5% liquid pool chlorine diluted with water, plus 2 ounces of Dawn dish soap in a 2-gallon sprayer). For specific stains, specialized cleaners may be needed.Is post-treating necessary?
While not always necessary, post-treating with a 2-4% SH solution enhances the longevity of your clean by removing residual stains and killing bacteria or mold, ensuring surfaces stay cleaner longer.Can I pressure wash without pretreating?
Yes, but pretreating with a 2-4% SH solution makes the process more effective, saves time, and ensures better results, especially for tough stains.How long should I let the pretreatment sit?
Typically, 5-10 minutes is sufficient for the chemicals to break down dirt and stains.What safety precautions should I take?
Always wear protective gear like gloves and goggles, and ensure the area is clear of people and pets while working. Use sodium hypochlorite carefully to avoid damage to surfaces or vegetation.