Okay, I thought I'd offer an experience I had cleaning my pine shed . This shed is 3-4 years old and had no sealer applied. Because this is my own, I was able to try a few things in different areas to determine the results.
First, I applied EFC-38 on the front of the shed using the recommended 8oz per gallon. Using a hand pump sprayer, I gave the front a good coating and allowed to dwell for 15-20 minutes. Any longer and it would have dried. After rinsing thoroughly I allowed the shed to dry. Sad to say there wasn't a significant change. I applied a second coat and contributed some muscle and a scrub brush. Yes, it did look better but no much. I was very disappointed.
Second, I decided to give the EFC-38 another try on another side of the shed by increasing the mix to 12 oz per gallon and following the same process. Again, I was disappointed. The grey remained, maybe a little lighter in some small areas on each board but nevertheless it was still grey with all of the (mold, mildew, algae) along the bottom two feet of the wood.
Third, I decided to apply a bleach mixture (50/50) of household bleach to water. As soon as the bleach hit the wood the color came up and the mold began to disappear. I allowed the bleach to stand for 10 minutes before rinsing and rinsing and rinsing away. Now the entire shed looks super.
So, what is it that I should take away from this? I expected EFC-38 to deal with faded, grey wood and it didn't. I expected this product to cut through any mold, mildew..etc but it didn't. Even my test area (small) using HD80 didn't eliminate the greying and instead made it darker. That stumped me. Using an inexpensive solution of 50/50 bleach solved the problem.
Okay then, when do I use EFC-38? Why didn't it work on a pine shed that was grey and molded from four years of sun and shade exposure? I don't have confidence in doing a customer's deck with this product having gone through this experience.
I could really use the wisdom of those folks beating the drum for this product and it's sister product HD-80. Where did I go wrong... or did I? I am truly looking forward to the feedback and lessons this forum can supply.
Paul