Eco-Friendly Methods for Removing House Paint: Scrapping, Sanding, or Chemical Stripping?

Introduction

I worked as a carpenter for over fifty years, forty of them in the restoration field. Throughout my career, I have witnessed a wide range of methods for removing external house paint. My experience has led me to conclude that certain techniques can be detrimental, especially when it comes to pressure washing and chemical stripping.

Why Pressure Washing and Chemical Stripping Aren't Always the Best Choice

Pressure washing, a common method for removing paint, can have significant drawbacks. It can abrade the wood, forcing water into the wood, cracks, or joints in finishes. This can lead to long-term issues as water migrates out and causes additional damage. Moreover, pressure washing can even dislodge pieces of trim, and force water through penetrations like windows and doors.

Chemical stripping methods marketed as superior often contain caustic substances that are messy, environmentally harmful, and can cause serious health issues, such as skin contact, eye irritation, and fume inhalation. The residue also needs to be pressure washed, often at a lower pressure, which can further damage the substrate.

The Best and Least Popular: Scrapping and Sanding

While it may seem counterintuitive, manual scraping and sanding are often the best (though least popular) options for removing old paint. These methods ensure a thorough and controlled removal process that minimizes the risk of damaging the substrate or causing long-term problems.

To start, remove all easily accessible flaking paint with a scraper. Follow this by sanding the surface to achieve a smooth finish. This process is labor-intensive and physically demanding, but it is essential for ensuring a successful and long-lasting paint job.

Preparing for External Paint Removal

Before diving into the paint removal process, it's important to prepare the surface. First, soak the wall in TSP (trisodium phosphate) using a soaker hose. Let it sit for a few minutes, then agitate the wall with a broom or brush to remove stubborn spots. Finally, thoroughly wash the area.

A sub-2000psi pressure washer is typically used to clean the area, flaking off any loose bits of paint. However, at this pressure, any wood rot will be blown out, but the area will not be obliterated as it might with a higher-pressure gas unit.

Pay special attention to areas that show signs of rot. If rot is present, the affected area must be cut out and replaced as soon as possible. The surface should then be allowed to dry for at least a day, ideally a few days, before proceeding with further prep work, such as scraping or sanding, and priming if a color change is required.

Conclusion

While pressure washing and chemical stripping may seem like quick and easy solutions, they often lead to long-term problems. Manual scraping and sanding, although labor-intensive, provide a controlled and safer method for removing old paint. By following the steps outlined in this guide, you can ensure a successful and eco-friendly paint removal process that preserves the integrity of your exterior surfaces.