# preserving wood copper naphthenate



## peteuga (Dec 10, 2004)

We are planning to start constructing a bridge on a bike / hiking trail. I am reading the USDA Standard Plans for Single Log Stringer Trail Bridge, and it says I should preserve our wood and it recommend copper naphthenate. Does anyone have experience with this stuff? Where can you buy it? 

The trail is in the Atlanta, GA area, we have white oaks, red oaks, hickory, hornbeam, American hornbeam dog wood, and some cedars in the area. Opinions on which is best?

I would like to find one freshly blown over so I don't have to cut a living tree. Span is going to be 10-12 feet.


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## LarryFahn (Jul 19, 2005)

White Oak is your best bet that I know of.


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## bsieb (Aug 23, 2003)

You won't have to treat the cedar. (Personally, I wouldn't put copper naphthenate or any other poison into a natural environment.) I would put the log stringer on a stone footing so it doesn't directly contact the soil. Looking at the recommended stringer diameters... any sound log 16" - 24" in diameter will last a looong time!


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## peteuga (Dec 10, 2004)

what about simple treatments such as polyurethane? Would you invest time painting the wood with that? I would be willing to spend a little extra time / money if the paint increased the structures life span and few years.


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## Woodman (Mar 12, 2006)

I have used Copper Nap on bridge construction in Bend OR, kind of nasty stuff. That was treating a western tree (doug fir) being used for a single log bridge and free span of 40'.

I would only use locust for stringers and if you dont' have such then go with treated fence post round poles avialble at Tractor Supply. White Oak makes for good 2x deck boards if you have a local mill that can supply such. I would not recomend white oak for stringers.

At Trail Dynamics, we only use rough cut treated southern yellow pine for all of our bridges (deck boards). May be hard to get if you are not using much.

Woody
Trail Dynamics LLC


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## dlennard (Jun 22, 2011)

The cedar would be best if you can find big enough trees that have old growth. If buying new cedar it does not last very long as it is fast growth. The others won't last very long from rot and termites, but putting them up on rocks and not letting them touch the ground would help. Pressure treated is your best and longest lasting solution in the south. Make sure you get ground contact pressure treatment. I live at the beach and we build houses on 10"x10" pilings driven 16' in the ground. we can get 8x8 or 10x10 pilings up to 34' long. I used some 8x8's to make some skinnies and they worked great. I think a 8x8x20' was around 40.00.


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## NEPMTBA (Apr 7, 2007)

Second growth White Oak is much stronger than first growth but I doubt you would find first growth...

...farmers here in NEPA have used hickory for fence posts for years upon years they really don't rot even below ground level. Most of the original fence posts along the Pa Turnpike were hickory.

I would stay away from any chemicals especially over water.


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