Replies

1. 
   YesMaam27577 | Nov 10, 2009 03:31am | #1

   Water in wood when its painted will not be likely to rot the wood.

   Instead, it will cause the paint to peel.

   I won't be laughing at the lies when I'm gone,
   And I can't question how or when or why when I'm gone;
   I can't live proud enough to die when I'm gone,
   So I guess I'll have to do it while I'm here. (Phil Ochs)

1. 
   timc | Nov 10, 2009 04:09am | #2

   Is there any way to avoid that? Are there products e.g. primer and top coat that you would recommend? Is there really only one way to avoid peeling i.e. by using dried lumber?

1. 
   YesMaam27577 | Nov 10, 2009 06:46pm | #4

   Water in wood will always "try" to get out when the air is dryer.Water in the air will always "try" to get into wood when the wood is dryer.(Water in the form of moisture or vapor)In both cases, the water WILL succeed. Regardless of whatever paint or coating you put on the wood.And when water exits wood through a painted surface, it has the effect of pushing the paint off with it -- blisters and cracks will eventually appear, or outright peeling.But the good news is that paint will slow the transfer process.But the bad news is that if there's a lot of water in the wood when you paint it (like there is with green wood, or new treated wood), you've acceelerated the peeling process.Because the water WILL succeed in getting out, taking the paint bond with it.

   And I've never seen or heard of any product that changes that. If there were, why would lumber mills still have kilns, and huge amounts of inventory air drying?

   I won't be laughing at the lies when I'm gone,
   And I can't question how or when or why when I'm gone;
   I can't live proud enough to die when I'm gone,
   So I guess I'll have to do it while I'm here. (Phil Ochs)

2. 
   DonCanDo | Nov 10, 2009 04:23am | #3

   It's true that latex paint breathes better than oil paint, but there are limits to how much moisture can escape without causing peeling.  I don't know what those limits are and I suspect it's unknowable because of variables like humidity, temperature and sun.

   Generally, it's better to use an oil-based primer for exterior surfaces so you may wind up with peeling even if the material were appropriately dry.

   If you must use green wood, can you wait before painting it?  In the summer, it would not be unrealistic to wait months.  In the winter, you would need to wait until spring.