What paint should I use on treated posts outside?

Hey guys. I put in a bunch of posts on my dried out pond last summer, in hopes to put a deck on it this summer. Well, I special ordered some treated posts that were rated for under water application (I think they were called .02) and I thought that meant that they would be resistant to freezing and cracks.

I never filled the pond, but after the winter, some of the posts have huge cracks in them. Like, one of them looks like it's split right down the middle.
Now, that I see that, I figure I probably should have painted them before the winter.
Anyway, is there a way to fix them? Can I glue them back together and then paint them? If so, what kind of paint should I use? Water-based will make the cracks bigger if the paint gets in them, right? Should I used an exterior oil-based primer? Thanks.

 

You dont want to paint them. Treated lumber is injected with chemicals so they are saturated with water and painting them will just peel off as the water dries out.

Stain, yes, paint, no.

As far as the cracks, that's the nature of the treated wood, try to fill/repair and it will just fall out as the wood shrinks as water exits.

 

Those cracks are called checks. It's natural, but properly kiln dried and treated wood will make it minimal. Treated wood will not be impervious to the freeze/thaw cycle. If water gets into the cracks and freezes it will expand and proceed to crack the wood. It can get so bad that it will split the wood in half. However, that is not typical. You might consider a wrap that will hold the post together if it gets bad enough. Something like a water cured wrap sold in many home improvement stores.

 

I agree, stain but not paint. Waterbased stain will not make the cracks bigger.

Depending on the crack and how it's situated you might drill and bolt it to hold it together.

 

To add to Marksr's suggestion, you can also lag screw or bolt a plate between the crack.