Protecting 4x4 fence post from rot

John Hyatt · Jun 4, 2014

Railroad ties last because they are sitting on gravel. Creosote has no protection from rot or bugs..

J.

hdavis · Jun 4, 2014

ArtisticDecks-Bob said:
The PT of today is very different than 15 or so years ago and it will rot.

Use posts rated for marine exposure - they have much better protection.

hdavis · Jun 4, 2014

FWIW, I get 10' bark-on cedar fence posts for $4.50 here. If I wanted them to last longer, I'd char the part to be buried.

hdavis · Jun 4, 2014

John Hyatt said:
Creosote has no protection from rot or bugs..

It has to be very high levels - something you aren't going to get with a brush or simple dip. Once they crack through the protected layer, they go just like any other wood.

Donohue Const · Jun 4, 2014

I have been thinking about trying to do this on the pole sheds I build
I have thought about wrapping the post at ground level with something like grace ice and water shield.
Water would not get in between the post and ice and water since that would be covered by the shed wall
Is this a terrible idea?

John Hyatt · Jun 4, 2014

Yes.

J.

ArtisticDecks-Bob · Jun 5, 2014

Do you gentlemen know about bo-dark? Farmers have used those trees for fence posts for near on a 100 years and I bet they are still there and in good shape. A bo-dark tree makes a chain saw cry.

Bob

jlsconstruction · Jun 5, 2014

ArtisticDecks-Bob said:
Do you gentlemen know about bo-dark? Farmers have used those trees for fence posts for near on a 100 years and I bet they are still there and in good shape. A bo-dark tree makes a chain saw cry. Bob

Never heard of it. We have an over abundance of locust around here, that's what the farmers use

Tinstaafl · Jun 5, 2014

John Hyatt said:
Railroad ties last because they are sitting on gravel. Creosote has no protection from rot or bugs..

I dunno, John. Phone poles are treated with creosote, and they last longer than any deck posts I'm aware of...

jlsconstruction · Jun 5, 2014

We have a railroad tie retaining wall that's holding up our driveway at our lake house. It's about 10' tall. It's over 30 years old

Munanbak · Jun 5, 2014

I often remove old railway ties sitting in dirt in people gardens. They are usually hollow and full of bugs.

hdavis · Jun 5, 2014

Munanbak said:
I often remove old railway ties sitting in dirt in people gardens. They are usually hollow and full of bugs.

I haven't seen anyone buy new railroad ties. I've seen people buy ones that had pulled up due to cracks (these will rot fast if not treated), and I've seen fake new ones.

Quad Racer · Jun 5, 2014

It depends on the fence I guess.

But do any of you hang a new fence on the existing posts when you bid? I figure the post really only needs to last as long as the fence it supports.

Im not saying I haven't seen a perfectly god fence laying on the grass with broken posts, but that's the exception rather than the rule.

hdavis · Jun 5, 2014

Tinstaafl said:
I dunno, John. Phone poles are treated with creosote, and they last longer than any deck posts I'm aware of...

All the creosote ones (cedar posts) are considered hazardous waste now. The crossties were also cedar that was incised and pressure treated. Roughly 3X5X8', they make pretty good fence posts after their electric service life for a couple decades or so. The creosote eventually leaches out, it isn't entirely fixed into the wood.

Railroad ties are a little different - they were various hardwoods (including white oak and chestnut), and some tended to split worse than others. If they split, they didn't last long, since the untreated center became exposed.

Creosote effectively prevents rot and insects, but the concentrations have to be over ~6 wt% to work and the wood can't split after treatment.

hdavis · Jun 5, 2014

ArtisticDecks-Bob said:
Do you gentlemen know about bo-dark?

Also called Osage Orange. Harder to get some places than others...

Rio · Jun 5, 2014

John Hyatt said:
Railroad ties last because they are sitting on gravel. Creosote has no protection from rot or bugs..

J.

Telephone poles are or were soaked in creosote I believe and the bugs leave them pretty much alone......
From Wiki on the subject:
Traditionally, the preservative used was creosote, but due to environmental concerns, alternatives such as pentachlorophenol, copper naphthenate and borates are becoming widespread in the United States. For over 100 years, the American Wood Protection Association (AWPA) has developed the standards for preserving wood utility poles. Despite the preservatives, wood poles decay and have a life of approximately 25 to 50 years depending on climate and soil conditions, therefore requiring regular inspection and remedial preservative treatments.[4][5][6]

hdavis · Jun 5, 2014

A quick bit of history. Charring posts was recommended practice before there were preservatives. It created some surface creosote, and destroyed sugars close to the surface that insects and fungi could eat.

If charring wasn't possible, then smearing the wood with charcoal from a fire was recommended. Probably better than nothing

Golden view · Jun 5, 2014

I can still get .60 PCF treated 4x4s, but most are .4 or .20 now.

I don't have any 30 year old fences to base this on, but running the concrete above grade and sloping it seems to help a lot. More work to make it look nice.

jb4211 · Jun 5, 2014

Golden view said:
I can still get .60 PCF treated 4x4s, but most are .4 or .20 now.

I don't have any 30 year old fences to base this on, but running the concrete above grade and sloping it seems to help a lot. More work to make it look nice.

I don't like the way concrete above grade looks for fence posts. Just my opinion

John Hyatt · Jun 5, 2014

Tinstaafl said:
I dunno, John. Phone poles are treated with creosote, and they last longer than any deck posts I'm aware of...

I base my understanding on retaining walls I have torn out. The timbers were rotted and infested with termites. It's a given they were used ties.

The ends of the deadmen are always rotted 4'' in or so. I don't do many walls but when I do they are built with ground contact 6x6 , glav threaded rod and big ass washers for the deadman, and a generous lathering of Copper Green. For what it does CG is cheep to bad blackflag got out of selling it when I saw this happening I bought all Amazon had at the moment.

It only takes one picture for the Wallet to compare what they have and what I can give them far as retaining walls go. They are good money.

JonMon www.deckmastersllc.com

Protecting 4x4 fence post from rot

John Hyatt

hdavis

hdavis

hdavis

Donohue Const

John Hyatt

ArtisticDecks-Bob

jlsconstruction

Tinstaafl

jlsconstruction

Munanbak

hdavis

Quad Racer

hdavis

hdavis

Rio

hdavis

Golden view

jb4211

John Hyatt

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