To Paint or Not to Paint that is the ?

ezrollin

Seaman
Joined
Jul 18, 2009
Messages
67
I'm redecking my 24' pontoon boat with 3/4" marine grade AB pt / kiln dried plywood.On the top side I'm putting Marideck vinyl using MD 101 adhesive.I have though of painting the bottom with a latex deck paint to keep out moisture and ward off fungus etc.Some think it's a good idea but others say no,wood has to breathe and that paint the bottom will trap moist inside the wood.Opinions are OK but I would like something based on facts as to the real facts.
 

Redneck_Randy

Petty Officer 2nd Class
Joined
Feb 7, 2011
Messages
183
Re: To Paint or Not to Paint that is the ?

Common sense. Look at it this way. Painting the bottom will create a bowl affect trapping water from draining out the bottom.
 

EGlideRider

Lieutenant Junior Grade
Joined
Dec 14, 2008
Messages
1,000
Re: To Paint or Not to Paint that is the ?

+1 for Redneck or you will be sorry.
 

ezrollin

Seaman
Joined
Jul 18, 2009
Messages
67
Re: To Paint or Not to Paint that is the ?

I found an interesting article on wood finishing that may be of interest to some of you,it certainly increased my knowledge.It states that if wood painted on all sides absorbs water thru cracks or breaks in the paint it will retain the water longer and can contribute to rot,although I don't know if a layer of water based adhesive an vinyl would have the same affect.I do know from observation that the bottom of pontoon boats with marine treated plywood seem very resistant to rot.I think I will only paint the outside edges,the edges absorb water much easier than the finished surfaces.http://www.toolbase.org/PDF/DesignGuide ... g_Wood.pdf
 

bigdee

Commander
Joined
Jul 27, 2006
Messages
2,667
Re: To Paint or Not to Paint that is the ?

Every old plywood deck that I have seen always shows rot on the top side and the bottom side usually looks surprisingly good.
 

PlanB

Seaman Apprentice
Joined
Mar 1, 2003
Messages
39
Re: To Paint or Not to Paint that is the ?

My ten year old pontoon deck is as good as the day I bought it (Misty Harbor). It stays 8 months a year bobbing in the lake. Looking at the bottom of the ply decking it would appear to be some type of pressure treated plywood as it has the greenish look similar to treated lumber.
 

rogerwa

Commander
Joined
Nov 29, 2000
Messages
2,339
Re: To Paint or Not to Paint that is the ?

Before you use the Marideck product, there is another product out there that will not a weld in the middle. My understanding is that Marideck has a weld seam in the middle. Another site carries a product that is made from a continuous sheet. PM me as I do not want to break link rules..
 
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