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Discussion Starter #1
Hey guys and gals. I was hoping to get some input on protecting 4x4 fence posts from rot. They always seem to rot just below grade, making demo a snap. I think part of the problem is that the water may be sitting on the concrete just below grade, or that there is nothing protecting the wood from the freeze/thaw cycle (I'm in Ontario).

I have a project coming up, and we are building a fence right beside a swale. I haven't found anything local to serve my purpose. I had some thoughts on wrapping the post at grade with blue skin or spraying with rubberized tar. I'm not sure if the tar would be harmful to the surrounding area, though in this case there are no gardens or plants to really worry about.

Wood. Neighbours have wood, neighbours neighbours have wood. Wood. We're building with wood. I won't rule out a steel post in the future, or for the sake of discussion. Does anybody have any input? Or should we just expect to replace sooner than later....

What are your thoughts on preserving a wood fence post?
 

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Are we talking PT, cedar? I've seen people use a tar like product on timbers and it flaked off, all it did was trap moisture.
 

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Discussion Starter #4
Are we talking PT, cedar? I've seen people use a tar like product on timbers and it flaked off, all it did was trap moisture.
Pressure treated fence post. I'm curious how the tar could trap moisture? I think if it were applied just above grade to 6" or so below grade, it would protect from moisture.. no? I think I'm over thinking this...
 

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I think it may get pricey using steel posts. Though I do like the idea of steel posts with wood fencing.
Nah, the customer pays for it. They already know that wood sucks, after all that's why they need to replace the fence. Show them how steel is superior. I do it all day long with deck frames, can't imagine it'd be too hard with fence posts.
 

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24 years ago I built a fence around my property.

4x4 PT post, 2' deep, painted with Copper Green.

Just replaced two gate posts because my FIL let the wind catch them
and broke them.

Pulled the posts and they show NO signs of rot...

Nor do any of the others.
 

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That wood degredation is usually from wetting / drying cycles, and with PT SYP is much worse if it's exposed to direct sunlight. It's a little better if you raise the concrete above the soil surface, and slope it away from the post. If you're a glutton for work, you can drill a hole down the center of the post, and fill it with antifreeze every year.
 

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I've heard of wrapping the lower part of a post in galvi or copper, but haven't done it.
I've seen that, galv, but after 15 years the posts were rotted and broke off at ground level.
 

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24 years ago I built a fence around my property.

4x4 PT post, 2' deep, painted with Copper Green.

Just replaced two gate posts because my FIL let the wind catch them
and broke them.

Pulled the posts and they show NO signs of rot...

Nor do any of the others.
Also, the PT and wood from 24 years ago was quite different from today's...
 

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John Hyatt
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Copper green does work. Stops bugs and rot from going on in any wood and stops rot that has already started.

Joe Wood, www.woodsshop.com taught me the copper flat stock trick. Fastening the metal with copper nails a few inches above and below the contact area. The idea is the more copper gets wet the more it leaches and the more protection the post gets.

That came from old Japan, sometimes I think Joe was brought up in a oriental family in another life. Most all his work has that...slant..to it.

JonMon www.deckmastersllc.com
 

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Discussion Starter #17
These are all great ideas.

Painting with copper green sounds easy and reasonable. Though the 4x4 are usually already quite wet.

Wrapping in copper or galvanized steel is a good idea but might get pricey again.

I liked the idea of applying tar around grade, cheap, quick, maybe poisonous...

I find I smell like copper green for the rest of the day after using it.
 

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The PT of today is very different than 15 or so years ago and it will rot.

As I see it you have three choices:
1. Use PT 4x4 posts and watch them warp like a banana,
2. Use a schedule #40 or a .095 galvanized 2-3/8 inch post and wrap it in wood, here we would use cedar.
3. Up size your posts to 6x6's
4. If possible in your area use creosote to treat the bottom of the posts. There are a lot of rail road ties that have lasted decades.

Bob
 
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