Seal the ends of Pine T&G Porch?

August 26, 2016 6:52 AM

I just put in a new floor on my front porch. It's (nominal) 4x1 pine tongue and groove with the endgrain on the front edge. The floors on these kinds of porches rot at the edges pretty quickly, but it is the historical style. Can I seal the end grain with silicon caulk after painting? The other ends are against the house and would not be sealed. The porch will be heavily painted (primer x2, floor paint x2).
posted by OmieWise to Home & Garden (7 answers total)

Better a poly urethane floor finish would work but the best thing would be to treat the ends with a Clear Penetrating Epoxy Sealant or CPES before painting.
posted by Mitheral at 7:39 AM on August 26, 2016 [2 favorites]

Silicone isn't really made for that application. It'll look weird, and over time it will peel off. I agree with Mitheral; an epoxy sealant is the gold standard for what you want to do. You apply it before painting and paint over it.
posted by Anticipation Of A New Lover's Arrival, The at 8:21 AM on August 26, 2016

If you don't want to get as fancy as epoxy, end cut protectant (the stuff you use to protect the cut ends of pressure treated wood) wood probably be good enough considering the expected lifetime of the rest of the porch. Apply before painting, of course, and two coats probably wouldn't be a bad idea (it readily soaks into end grain).
posted by ssg at 10:05 AM on August 26, 2016

I think sealant applied after painting will be probably be of limited benefit, likely to flake off pretty quickly and look bad as well. It might be worth removing the paint with a power sander to apply a protective treatment to the end grain, before re-priming and painting. Otherwise I would just try and keep the paint up, or wait for it to start to degrade before doing the sanding/sealing routine.

FWIW, three years ago I did this project at my house, replacing the tongue-and-groove pine porch boards with new. I primed all sides before installation and put caulking between the tongues and grooves (big mistake was not using paintable caulk). After the boards were installed, I cut the exposed ends, ran a router to round them over, then used an expoxy sealant on the end grain before painting.
posted by exogenous at 10:38 AM on August 26, 2016 [1 favorite]

At some point you're going to really wish you never had done that. Silicone is really hard to strip away and/or repaint.

Your primer and deck paint are the appropriate means of sealing the wood.
posted by humboldt32 at 1:35 PM on August 26, 2016 [2 favorites]

i know you are probably set on painting your porch, but i think you will get better wear with a penetrating oil finish. HD is selling an "australian timber oil" which is probably fine. you could try a sem-transparent stain/sealant as well if you want a color. aside from not changing anything, the silicone caulk is unpaintable so you won't be able to repaint your porch. the nice thing about a penetrating oil is that you can easily reapply it easily every season, which will drastically extend the life of your porch.

the reason why the porch rots from the end is that either the porch roof doesn't extend far enough over the floor, the drip line is faulty, or the porch is getting backsplash from the ground. once water gets into the wood, your paint is sealing in the water as it is a membrane, rather than keeping it out... also, if your porch floor is douglas fir, paint generally doesn't adhere to fir very well, which will shorten the life again.
posted by ennui.bz at 3:53 PM on August 26, 2016 [1 favorite]

Response by poster: Thanks everyone. I have to paint for reasons having to do with the historical district I'm in. There is a drip edge problem, which I am correcting, but the porch still gets wet because of prevailing winds etc. I appreciate all of the responses here.
posted by OmieWise at 7:42 AM on August 29, 2016