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Painting Damp Wood

sammy's picture

Is there anything wrong with painting a damp porch fioor.

(post #62854, reply #1 of 11)

No problem at all ... go ahead and do it.  And then plan to do it again in about 6 months when all the paint blisters off.  But you'll save on paint initially, cuz it wont soak in, so a little goes a long way. 


 


Whenever you are asked if you can do a job, tell'em "Certainly, I can!"  Then get busy and find out how to do it.  T. Roosevelt

I'm sorry, I thought you wanted it done the right way.

(post #62854, reply #2 of 11)

I have an old church that I have been painting for eight years, so have have learned a lot about painting. I finally got a moisture meter [approx $25--or rent one] to make sure the wood is dry enough to paint. It has two probes that sink a little way into the wood. On older structures, the horizontal surfaces like window sills and water tables tend to crack and won't hold the paint due to expansion and contraction, so I treat them with liquid e.pox.e first. If your wood is damp you can put a work light/heat lamp on it for awhile, but be careful of fire. Also, cover it at night to prevent condensation getting it wet again before you paint it, depending on the season.

(post #62854, reply #3 of 11)

My opinion is that it will be OK as long as you are using water base paint.

(post #62854, reply #4 of 11)

My dear, I believe bad advice is what sent you to prison in the first place. Just trying to lengthen the stay?

"If you pick up a starving dog and make him prosperous, he will not bite you. This is the principal difference between a dog and a man." - Mark Twain

Real trucks dont have sparkplugs

(post #62854, reply #6 of 11)

I was sent to the big house because I took bad advice, not for giving it. Painting damp wood is done all the time here. It's hardly ever dry. Wet wood is another story though. How do you think houses get painted in Seattle or New Orleans? Never dry there either. But of course it is best to paint dry wood.


Edited 10/2/2004 8:38 pm ET by Martha Stewart

(post #62854, reply #7 of 11)

yeah ... but in New Orleans everyone's drunk all the time so no one notices.


or cares!


 


Jeff


Buck Construction, llc   Pittsburgh,PA


     Artistry in Carpentry                

    Buck Construction

 Artistry In Carpentry

     Pittsburgh Pa

(post #62854, reply #8 of 11)

The weather is damp here too, but no pro paints damp wood here.

I can think of three jobs where DIYs painted damp wood and it was coming backoff in 2 years. The pros jobs last more like ten or so.

 

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Oh Well,

We did the best we could...

(post #62854, reply #9 of 11)

How do the professional painters handle damp weather? I know you can't only work when wood is completely dry. Perhaps my idea of damp and yours are different. It sounds like my damp might be your dry.

(post #62854, reply #11 of 11)

we use tents, tarps, and pre-primed wood.

On repaints, we prime anyting exposed the same day it is scraped and sanded.

That way the water doesn't get into the wood

 

 <?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />


Welcome to the
Taunton University of
Knowledge FHB Campus at Breaktime.
 where ...
Excellence is its own reward!

 

 

Oh Well,

We did the best we could...

(post #62854, reply #5 of 11)

Damp as in the lingering effect of a light rainfall a few hours earlier?  Here adhesion of water based paints would not be (seriously) impaired.  It could conceivably even be improved.


I am thinking your question was more in terms of persistant dampness.  Then I'd take Ed Hilton's advice to which I will add that sealing a wooden surface that has on ongoing souce of moisture may cause damage to the wood as it cups.  

(post #62854, reply #10 of 11)

Excessively damp wood brings wood cellular chemicals to the surface as the moisture migrates from a more humid or damp environment to a less humid environment during the evaporative process. Such water vapor substrate permeability both attacks the paint film plus causes it's adhesive qualities to fail allowing the film to be "lifted" from the substrate.

Adsorption also occurs during early evening when the dew point is lower, so any painting to be done when the substrate is ready should be done late morning when the dew has burned off, yet stop painting in early afternoon so evening dew does not prevent the paint film to coalesce properly or it will fail.

So you have two main concerns, existing moisture content, and surface dew.

So assuming that the wood is not exceptionally damp, you will only have about a 4 - 5 hour window during which you can apply paint, less if you use a Xylene water bourne paint, since Xylene, while water soluble, when part of a paint ingredient, will not tolerate moisture on the substrate to be painted.

Finally, do not use an alkyd primer since they tend to dry more brittle or less flexible. Apparently, in your case, dampness is a static condition and an alkyd paint will split as the wood expands and then contracts as the wood moisture content varies substantially.

You might want to pose your question, geographical location, and more pertinent info on the paint forum.

http://www.painterschatroom.com/