Will Cypress rot?

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Forum topic by bingo296 posted 785 days ago 4586 views 0 times favorited 10 replies Add to Favorites Watch
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2 posts in 786 days

785 days ago

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

View Dallas's profile


2869 posts in 1120 days

#1 posted 785 days ago

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!

View HerbC's profile


1162 posts in 1492 days

#2 posted 785 days ago

+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!"

View kizerpea's profile


746 posts in 1000 days

#3 posted 785 days ago

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….


View waho6o9's profile


4837 posts in 1210 days

#4 posted 785 days ago

Use 2 part poly urethane. Easy peasy and clean.

Secure set is used in industrial applications as well.

View DKV's profile


3076 posts in 1137 days

#5 posted 785 days ago

I use metal post supports.

-- 2014 will be a different least for me it will.

View BentheViking's profile


1752 posts in 1197 days

#6 posted 785 days ago

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

View nailbanger2's profile


959 posts in 1776 days

#7 posted 785 days ago

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

View RickLoDico's profile


55 posts in 1694 days

#8 posted 784 days ago

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.

View Doss's profile


779 posts in 897 days

#9 posted 784 days ago

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

View eric122's profile


92 posts in 1643 days

#10 posted 744 days ago

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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