We just used this on our 13 year old deck that had 3 or 4 layers of stain and I'm quite pleased with this stripper. We, liberally, applied the stripper with a sprayer. Let it sit for 15 minutes making sure it stayed wet by spraying more stripper if needed. Scrubbed the area with a brush and then hit it with the pressure washer. For the most part, with just one application, almost all the stain was removed. We would definitely use this product again.