mildew?

[rickt761 14]

I recently sealed a deck with Cabot Decking Stain. We poured all five one gallon cans into a 5 gal. bucket and stirred to get the proper consistancy.The deck looked beautiful. Two days after we got done I got a call from the deck owner telling me that there is a white film over much of the deck and that sections of the deck looks like it needs a second coat. Needless to say I went over there to see for myself. Sure enough there was a white film in areas and plain water would not wash it off. There also were areas that looked like it wasn't totally sealed. We hand brushed the entire deck so I know that proper amount of sealer was used over all the deck.We also waited two full sunny days before sealing.

Some info that may contribute to this problem.

1. They are on a well so we were limited to how much water we could use.

2. We were not allowed to use any stripper or other chemicals other than soap. The deck had not been sealed for at least five years so most all old sealer came off.

3. Most of the problem area is where the most traffic occurs; to and from the door.

My questions are could that film be mildew? If so will bleach take care of it? If it isn't mildew what is it? How can I get rid of it? Can I apply a second coat over the questionable areas that look like they didn't seal right? They were not areas that might have still had some old sealer.

Any help will be greatly appreciated.

[big mike 14]

We were not allowed to use any stripper or other chemicals other than soap.

Why?

This sends a red flag up. What "soap" did you use, and did you rinse or neutralize? Also, what Cabot's product did you use? What was in the 5 gallon bucket prior to you mixing up stain? Mildew does not form that quickly, so I wouldn't worry about that.

Too many questions to give you a realistic answer. Do you have photos?

[Danny Bates 14]

Sounds like a moisture problem to me.

[rickt761 14]

Mike the reason we were not allowed to use chemicals is because immediately below the deck are dog kennels and she didn't want any chemicals to go there. This is an animal santctuary. We were originally going to attach a tarp to the underside of the deck but after close examination we felt that we can get by with just using laundry soap (generic) and water then diluting the soapy water when done. Almost all the existing sealer came off. The areas where it didn't come off we sanded. The wood in several places were time worn (dried out). She did not want to go to the expense of replacing those boards. It got up to about 84 degrees with high humidity that day though we were done before it got that hot.As I explained she was on a well so we had to wash the deck in stages for fear that she would run out of water or put the level too low.

The boards that were weather worn are some but not all the boards that look like they could use a second coat. As I explained we hand brushed the whole deck so we gave ample sealer everywhere.

The white film is puzzling because it appeared within two days of finishing. I usually use Wolman F & P and I have not had this problem with their product. But then again I am not sure it is a product problem. We did not neutrilize because with the exception of soap we did not use anything but water and sealer.

By the way the five gallon bucket we poured the sealer into was brand new so it had no prior ingrediants in it.

I hope this helps you understand my situation a little better.

[Adrian 155]

Mike the reason we were not allowed to use chemicals is because immediately below the deck are dog kennels and she didn't want any chemicals to go there. This is an animal santctuary. We were originally going to attach a tarp to the underside of the deck but after close examination we felt that we can get by with just using laundry soap (generic) and water then diluting the soapy water when done. Almost all the existing sealer came off. The areas where it didn't come off we sanded. The wood in several places were time worn (dried out). She did not want to go to the expense of replacing those boards. It got up to about 84 degrees with high humidity that day though we were done before it got that hot.As I explained she was on a well so we had to wash the deck in stages for fear that she would run out of water or put the level too low.

The boards that were weather worn are some but not all the boards that look like they could use a second coat. As I explained we hand brushed the whole deck so we gave ample sealer everywhere.

The white film is puzzling because it appeared within two days of finishing. I usually use Wolman F & P and I have not had this problem with their product. But then again I am not sure it is a product problem. We did not neutrilize because with the exception of soap we did not use anything but water and sealer.

By the way the five gallon bucket we poured the sealer into was brand new so it had no prior ingrediants in it.

I hope this helps you understand my situation a little better.

Rick761, please go to "my controls" and complete your signature line.