QUESTION FROM Paul

I used a water-based stain on my deck 2 years ago. Initially it looked good, but after a heavy snowfall melted it took most of the stain away and now it looks patchy.

A friend said I need to use an oil based stain, any recommendations?

ANSWER FROM POLICY-Wizard™

Hi Paul:

We should be able to help you. We can give you a much better answer once we understand you situation. So let's start with just a few questions:

1) What type of wood is your deck made of?

2) Could you please describe the process you used to apply the water-based stain (prep work you did, how many coats, were coats applied wet-on-wet, how soon afterwards did it rain, etc.).

Home-Wizard.com

FOLLOW-UP FROM Paul

Thanks for the response.

Unfortunately I've no idea what material the deck is as it was there when I bought the house. It looks like it's seen better days (I'll need to replace some pieces this summer).

For the staining I did, I first pressure washed (but gently) the deck. Then applied a deck cleaning agent.I applied 2 thin coat of stain using a long handled roller. The coats were applied a day apart. I still have some left over if the brand is important (I had thought of re-applying it but due to its performance I have decided to start-again). There wasn't any rain during the days it was applied.

Initially it all looked good, but as I mentioned we had some serious snowfall - for us anyway! - and when that melted it left obvious patches, literally looking like it had washed away the stain. Apart from some sheltered spots it is now pretty much all gone.

I've now pressure washed it again in preparation for removing some of the rotten boards and am therefore looking for a heavier, possibly colored stain, where I can blend old and new.

I appreciate your help and advice.

No rush - it'll be a couple of weeks before it's dry enough to attempt this project here!

thanks

ANSWER FROM POLICY-Wizard™

Paul:

From what you described, it sounds like the problem with your deck losing its stain in some locations may be caused by one of the two following scenarios:

1) not doing all of the steps required for staining your deck (or not doing them in the proper order); or

2) one or more of the steps not being done exactly properly.

Let's start with the first one. It sounds like you did a gentle pressure wash, then applied a cleaning agent, and then you stained the deck. Actually, the proper steps are: 1) sweep deck and rinse to remove debris; 2) apply a cleaner that is appropriate for the needs of your deck (given what it's made of, any mold or mildew, etc.); 3) scrub with a long-handled bristle brush; 4) power wash; 5) sand with a large orbital sander using 60-80 grit sandpaper; 6) apply stripper and then rinse; 7) apply brightener to return the deck to the proper pH after the stripper; and then finally 8) apply stain in accordance with the directions for the type of stain that you are using (which is different if you are using oil-based versus water-based, for example). Not doing all of these steps in this order maybe why you are have the problem with your stain not adhering in some areas.

Regarding the second scenario, your problem may be that one of the steps that you did was not done properly. For example:

1) If you did not completely strip away the old stain before re-staining. The correct way would be to thoroughly sand your deck, then apply the stripper, then apply the brightener to re-balance the pH and to open the wood pores . . . and then to apply the stain. Trying to get new stain to adhere to old stain may have caused your problem.

2) If you used water-based stain over an oil-based stain (or vice versa). If you are not sure what was there before, it could be possible that it was oil-based before, and you tried to put water-based stain on top of it (without completely stripping off the oil-based stain below it).

3) If you did not exactly follow the directions for the particular stain that you were using. For example, some stains have to be applied "wet on wet," where as others need to be applied "wet on dry."


Regarding your question of "oil-based stains versus water-based stains," the answer is a bit complicated. In the past, oil-based deck stains have been the preferred method to stain a deck, however these days the recommendation has changed to synthetic resins and a new generation of water-based stains. Originally, oil-based stains were preferred because they penetrated the wood well and were longer-lasting than water-based stains. However the problem with oil-based strains is that: 1) because they are made with natural resins, they attract mold and algae; 2) they are harder to work with; and 3) they are environmentally very un-friendly. In particular, to counteract the mold and algae problem, manufacturers put algaecides and mildewcides in these products, which are toxic and leach out of the wood over time, leaving the wood exposed and causing problems for barefoot children and the environment. As a result, a number of states prohibit the use of almost all oil-based stains. The good news is that there are new "synthetic resin" stains which have been developed that don't have the mold and algae problems of oil-based stains. And there are also a new generation of water-based stains which allow these stains to penetrate like an oil-based stain. So, the bottom line is that you should look at the new synthetic resin or water-based stains, and you should talk to your local paint store to see what would work best for your particular decking material, local weather effects, and how often you are willing to re-stain your deck.

One additional thought, you said that you were going to replace some of your boards. If you can take one of the old boards into your local paint stores, they should be able to tell you what your deck is made of, so that you can purchase the correct finishing products for it.

As I mentioned earlier, we are working on an article and video about outdoor decking that will be in our June Newsletter. It should be ready in about a week, and I will send it to you as soon as it is available.

We hope this is helpful. If you have any additional questions, just let us know.

Home-Wizard.com