How should I seal my outdoor Cypress porch posts?

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Forum topic by rachelpres posted 04-20-2017 02:48 AM 6299 views 0 times favorited 4 replies Add to Favorites Watch
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2 posts in 1208 days

04-20-2017 02:48 AM

Topic tags/keywords: cypress posts columns cure cured spar varnish oil linseed oil mineral spirits unfinished cypress raw cypress paint stain question rustic finishing veneering

Hi everyone. I’m new to this site, but I have enjoyed reading all the information so far. From everything that I’ve read, it seems like the best thing to use for sealing my outdoor cypress porch posts/columns would be to use spar varnish. We are building a new home and I have a lot of cypress: I have six (6) 13”x13” cypress posts across the front porch of my home with an 8”x13” header. I also have a side stoop post and 3 back porch posts that are 10”x10” square. And last but not least, I have eleven (11) cypress lentils above my windows across the front of my house. I love the weathered look of the unfinished cypress, and I also love the way it looks when it gets wet. I was advised by my house painter to use a marine varnish to just seal the posts. Since then, I have taken it upon myself to do a little research because we spent a lot of money on this wood and would like to maintain the integrity of the wood while also protecting it from the south Louisiana heat and humidity.

One website I came across suggested using Epifanes Marine Varnish in clear. Another video I came across suggested using equal parts boiled linseed oil and mineral spirits with 1/2 part marine (spar) varnish. Being that I am not really inclined to do all this work myself (because it’s a lot of wood, but I will if I have to) I would like to make sure that my painter isn’t just going to spray on a random marine varnish and call it a day.

Has anyone on here cured and sealed raw cypress posts and how did you do it? What are your suggestions?

Thanks in advance!


-- Live Your Life! You only have one! Rachel, Louisiana

4 replies so far

View papadan's profile


3584 posts in 4174 days

#1 posted 04-20-2017 03:15 AM

Hello Rachel and Welcome to Lumber Jocks. You said you like the weathered unfinished look of the cypress. I agree completely with you. Get a 5 gallon bucket of Thompsons water seal. It can be brushed on, but I prefer to spray it on. I use one of those pump up garden sprayers and just soak the wood down with it. It’s water based and water clear, wont change the look of the wood but will seal it from rain and sun damage. Repeat application every 2-3 years and your home will always look great.

View Aj2's profile


3184 posts in 2604 days

#2 posted 04-20-2017 03:41 AM

I think your nuts for spending any time or money toward a clear finish.Either leave them natural to turn gray or paint them and they will outlast any wood around them that’s not cypress.
I don’t know why papadan is recommending Thompson water seal is a very weak outdoor finish.

-- Aj

View papadan's profile


3584 posts in 4174 days

#3 posted 04-20-2017 03:57 AM

Thompsons is a weak product, that is why I said to reapply every 2-3 years. It will seal out the rain without changing the looks of the wood. Staying dry inside the wood is what prevents rot.

View Snipes's profile


459 posts in 3051 days

#4 posted 04-20-2017 06:50 PM

The problem with varnish is that it forms a film, so when it needs to be redone it can be a big chore.. I personally would not use a varnish but instead an oil or siding sealer of some sort. Penofin and sikkens are a couple of good ones, I’ve also used a behr product with good luck. If I were to use a varnish it would be the epifanes that you mentioned. Good Luck

-- if it is to be it is up to me

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