Hello, We had a new deck installed in the summer of 03, and had it painted in summer of 05 with Sherman and Williams water based semi-transparent stain. The deck is treated southern yellow pine. Two problems:
-We now have sap coming out of the knotts etc. More so on the areas exposed to direct sun. What to do?
– Some of the stain is pleeling off. Not related to above. What gives and what should be done other than scrape and repaint.
Thanks Rod
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Replies
Leave it alone and let it weather naturally.
Rod-
Is the deck PAINTED or STAINED? You mention both and there is a HUGE difference, but from your description, it's not clear. If it is peeling off, it is paint not stain. My advice, either live with it or scrape ALL of the paint off and then STAIN the deck. Paint will blister and bubble I guara-darn-tee it. No matter what you do, I have NEVER seen paint hold up on the flat surfaces of a deck. Water gets under it and bubbles it off. Paint doesn't soak into the wood, it sits on top and water can break the bond of paint and wood, especially on horizontal surfaces. STAIN on the other hand, soaks into the wood. You can get it in differnt levels of opaueness, but if you want color you want STAIN.
Mebbe Pro-Dek will come by, he's probably stained a deck or two and could reccommend something good. I think the guys here at one time liked Cabot stains. I use the Olympic from Blowes and it does pretty well on my pine deck. It needs redoing now, but I last stained 6 years ago.
I think that you put it on too thick.
With a semi-transparent stain there shouldn't be anything to scrape.
because of foot traffic and moisture on that horizontal surface, most deck finishes will only last a few years anyway.
The peeling could be related to the resins in the SYP. you should dry and sand any surface first before finishing. but SYP is one of those woods that is especially difficult because of the resins. The planer blades turned some of them on the surface to a wax that repels finishes. Sanding will open the pores and give some tooth or mechanical bond to the finish you chose.
Finally, I wonder why you would have used lumber with knots for a finished surface. In SYP, the sap can continue to bleed out for a dozen years. If you choose to paint, there are sealers that can help prevent some of that, but not all. One option might be to drill a small hole though the offensive knots in hopes that the sap will drain below instaed of puddling in a tacky pool
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A traditional fix for sap bleeding in the pines is to shellac the knots before painting. If you're using a stain product, this would prevent the stain from penetrating, so you'd have to stain first, and shellac afterward. But obviously, you'd have to shellac the entire deck and not just the knots, or you'd have an uneven finish.
Even so, as Piffin mentioned, deck finishes subject to shoe-traffic don't last very many years. The toughest deck finising product I know of other than epoxy floor paint is Sikkens Rubbol Dek. You might want to look into that. I don't know if it would stop the sap bleeding, though. Call Sikkens and ask them. Their technical advice service is pretty good.
Dinosaur
A day may come when the courage of men fails,when we forsake our friends and break all bonds of fellowship...
But it is not this day.
Thanks for the comments. The stain was probably but on too thick. As to the sap, I will probably scape and use alchol, I do not follow the suggestion to use shellac. I have used shellac to seal a pine outdoor table top the the result was a disaster. I now think of shellac as an organic product for interior use only. Is there something I am missing? Rod
When you say the result was a disaster, what exactly happened?
Dinosaur
A day may come when the courage of men fails,when we forsake our friends and break all bonds of fellowship...
But it is not this day.
You can't stop the sap from draining. But it is cleanable. Scrape off what you can with a putty knife, then use denatured alcohol to wash off the rest. Until all the sap is drained for the wood you'll have to continue doing this occasionally.
Nothing will stay on PT yellow pine for very long. It is a very fast growing species and the variation between summer and winter growth means splitting and checking. If you intend to paint or stain it, you will have job security for a long time.
Beat it to fit / Paint it to match
Turpentine is very effective in removing the sap.