Will Cypress rot?

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Forum topic by bingo296 posted 07-04-2012 12:01 PM 5894 views 0 times favorited 10 replies Add to Favorites Watch
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2 posts in 942 days

07-04-2012 12:01 PM

My wife has voluteered me to build a pergola for her. I am thinking about using rough sawn cypress for it. I will be using 4×6’s for the corner posts. Will they rot if set in the ground on a gravel bed with concrete poured around them? If so, what could I do to prevent rot but still use the cypress?

-- Save The Planet,

10 replies so far

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3285 posts in 1276 days

#1 posted 07-04-2012 12:11 PM

Everything will rot… even stainless steel if given long enough.

The best way I’ve found is to pour your footers, then embed a metal post support to keep the post out of the dirt and moisture.

-- Improvise.... Adapt...... Overcome!

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1246 posts in 1648 days

#2 posted 07-04-2012 02:36 PM

+1 on using the brackets.

Also, try to ensure you get posts that are “heart” cypress, with little or no sapwood. The heart is very durable but the sapwood will not hold up well.

Good Luck!

Be Careful!


-- Herb, Florida - Here's why I close most messages with "Be Careful!"

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746 posts in 1157 days

#3 posted 07-04-2012 02:38 PM

seal the bottom of the post with a oil based paint….the end grain is like a drinking straw…it will suck water up the post like a wick..if the top will b exposed seal it with candle wax…thats why lumber is painted on the end..hope this helps….


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5456 posts in 1366 days

#4 posted 07-04-2012 03:17 PM

Use 2 part poly urethane. Easy peasy and clean.

Secure set is used in industrial applications as well.

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3196 posts in 1293 days

#5 posted 07-04-2012 03:38 PM

I use metal post supports.

-- Have fun and laugh alot. Life can end at any moment. You old guys out there know what I mean...

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1757 posts in 1353 days

#6 posted 07-04-2012 06:47 PM

Don’t use cypress. Most of it comes from the wetlands along the gulf coast that are one of the biggest barriers to preventing hurricanes from doing damage to the area. I am by no means a tree hugger (I don’t think any woodworker really is), but just encouraging you to go with something like cedar that is a little less environmentally damaging.

-- It's made of wood. Real sturdy.--Chubbs Peterson

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971 posts in 1933 days

#7 posted 07-04-2012 07:05 PM

If you use metal post supports (and I do recommend them), seal any gaps with silicone to prevent water from getting in and sitting there. I can’t tell you how many porches I’ve found with rusted away Simpson strong tie buckets. They are not easy to re-install down the road!

-- Wish I were Norm's Nephew

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55 posts in 1850 days

#8 posted 07-06-2012 01:30 AM

Use Locust if it’s available in your area. Either Black or Honey will last for many years, even untreated, in direct contact with the soil.

-- He who fights with monsters might take care lest he thereby become a monster. And if you gaze for long into an abyss, the abyss gazes also into you.

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779 posts in 1054 days

#9 posted 07-06-2012 01:41 AM

You probably need to mention what area you live in so we can get an idea of how much sun and rain and snow… whatever you get.

It will rot, just slower than most species. Old-growth is the best, but obviously that’s not a great option for something like a pergola and definitely not cheap. The next best is heartwood as mentioned above.

You can get something like Woodlife Classic to further the rot-resistant characteristics of the cypress. You’ll still want to use something in the end like kizerpea said (using oil-based exterior paint base or colored) to seal out water.

Anchors as mentioned above work great.

If you’re going to all this effort, you least I’d do is get the anchors. If you can’t do that, I hope your soil drains well. You can then use concrete, but I’d definitely seal the wood with something a few days before you plan on putting them in. I put some fence posts in with about 3 or 4” of gravel at the bottom of the hole and then filled the rest with sand (about an inch) then concrete with a sloped top running away from the post. The previous posts lasted 12 years and they were still solid when I took them out.

-- "Well, at least we can still use it as firewood... maybe." - Doss

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94 posts in 1799 days

#10 posted 08-14-2012 03:49 PM

you could use anchor seal on the exposed ends of the post to seal them from moisture you could also use western larch lumber it is a pine but do to the high sap content the bugs and termites dont like it i made a set of steps for my aunt n uncle almost 12 yrs ago now and they are still holding up great alittle weatherd but still sound n solid u can use thompsons advanced water seal to maintain the nice dark ornage color of larch good luck 2nd wood choice would be old growth white oak its great for outdoor use or spanish cedar will work

-- eric underwood

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