Concrete Posts.

[Lloyd_E]

Ok... so after purchasing and putting in place 175 plus oak(because I got them cheap) 4"x4"x8' posts with 1"x6" rails; we are starting to replace them after only four years in the ground. I painted the ends - up to 48" - that were going into the ground with copper2 preservative plus a coat of driveway black sealer. After everything was up - approx 4 acres with various paddocks - I used Behr solid fence stain - black - over everything.

When I first started this project my good buddy suggested we cast concrete posts with slots for the rails and place them in the ground... I hesitated. Now I am rethinking the hole thing. I replaced 4 posts in May, have at least 6 more to do and just discovered a section with 5 posts rotten at ground level.

I know in England they use concrete posts and our recent trip to Williamsburg VA showed us very decorative concrete posts.

So my plan is this: 4x8 sheet of 3/4 plywood doubled to 1.5 inches placed on top of of 4"x4" x4' oak post for base. Screw 2x6 - top and bottom of sheet and space to make square posts with more 2x6. Make form for each post at top - decorative peak and place 2.5"x6.5" pieces of wood in mold to make slots for rails. Cast concrete and place a couple of 1/4" rebar on either side of slot forms for good measure.

After discussing this today with my buddy he suggested just placing a 1/2" piece of PVC pipe in the concrete at appropriate finished rail height O/C. The pipe would allow for a bolt to be used to attached rail... less fussing than trying to get posts and rails lined up.

So your thoughts! We have a heated building and a small mixer plus the tractor with 9"/14"auger and pallet forks...

I am thinking two 4x8 sets of molds. Rough guess is maybe 10 to 16 posts per cast.

The critical point is placing and aligning tops of posts along a run... can't just go and snip the top off quickly.

 

[rvaitor]

Ok... so after purchasing and putting in place 175 plus oak(because I got them cheap) 4"x4"x8' posts with 1"x6" rails; we are starting to replace them after only four years in the ground. I painted the ends - up to 48" - that were going into the ground with copper2 preservative plus a coat of driveway black sealer. After everything was up - approx 4 acres with various paddocks - I used Behr solid fence stain - black - over everything.

When I first started this project my good buddy suggested we cast concrete posts with slots for the rails and place them in the ground... I hesitated. Now I am rethinking the hole thing. I replaced 4 posts in May, have at least 6 more to do and just discovered a section with 5 posts rotten at ground level.

I know in England they use concrete posts and our recent trip to Williamsburg VA showed us very decorative concrete posts.

So my plan is this: 4x8 sheet of 3/4 plywood doubled to 1.5 inches placed on top of of 4"x4" x4' oak post for base. Screw 2x6 - top and bottom of sheet and space to make square posts with more 2x6. Make form for each post at top - decorative peak and place 2.5"x6.5" pieces of wood in mold to make slots for rails. Cast concrete and place a couple of 1/4" rebar on either side of slot forms for good measure.

After discussing this today with my buddy he suggested just placing a 1/2" piece of PVC pipe in the concrete at appropriate finished rail height O/C. The pipe would allow for a bolt to be used to attached rail... less fussing than trying to get posts and rails lined up.

So your thoughts! We have a heated building and a small mixer plus the tractor with 9"/14"auger and pallet forks...

I am thinking two 4x8 sets of molds. Rough guess is maybe 10 to 16 posts per cast.

The critical point is placing and aligning tops of posts along a run... can't just go and snip the top off quickly.

I have some plans for concrete posts. I think Portland was the sources. Give me a day or two to find them. I've got about 100 of these that have been in the ground 30+ year and the fence is still banjo string tight.

PM me if I forget.

 

[dmccarty]

I have thought of doing concrete posts myself so this is an interesting thread.

Instead of a PVC pipe to use to bolt the fence boards how about a slot cast in the post. A narrow slot that would allow the bolt to be shimmed to keep the fence board level. Similar to the idea of a slot to hold the fence board but instead of hold the board the slow would hold the bolt holding the board.

Hope that made some sense.

Later,
Dan

 

[Willl]

Have you priced out premade concrete posts ?

 

[RobertBrown]

Great Idea Loyd!
I have often thought of casting concrete to create structural elements but I don't have a need for fence post in a big enough quanity,or that kind of structural integrity or service life. PT posts still make sense for me.
What imediately comes to mind is steel reinforcement, and the fact that the post could or should be tapered, the top wider and heavier than the bottom. I'm pretty sure the rebar is going to have travel the length of the post, but I was thinking 3/8" a.t.r... I'm guessing it's cheaper.
Your going to have to decide on the type and strength of concrete necessary. I'm not sure if fiberglassed reinforced concrtete is going to work in this application. There is the problem of the concrete sticking to the wood. I think I've heard that diesel will prevent this but I think you'll agree that the form has to be reusable.
I hope you can keep us informed as to your progress.

 

[Lloyd_E]

Thanks all.

Willl... I live at the end of the world... the idea of buying concrete posts here is nil. But if it works I may get into the concrete post business. We can buy plastic posts and rails that get attached to concrete posts at ground level. A couple of well-off horse folks have done it but I heard the bill for about 10-12 acres is around $250,000 to $400,000!

Robert, I assumed diesel and used cooking oil(because I get get gallons for free - cooking oil that is) could be used as a release agent. Would 1/4 rebar work or is 3/8 better? And yes it would go almost 8 feet. We can buy it in 20' lengths here. So there will be some small pieces becoming larger ones.

Dan, I am thinking we are saying the same thing... I hope. If the post is 4" wide say the pvc will be 4"plus and be pushed into the concrete until it is flush. There will be 3 to hold 3 rails and the bolt will pass through the entire post and connect the rails which will overlap slightly I guess.


ravaitor - see I knew someone would have insight and support!!!!

 

[RobertBrown]

I picture your casting bed to look somthing like this. I was considering making mine in the ground but that's probably not an option where you live

 

[SandburRanch]

You might want to do some testing with the cooking oil for as a release agent. I haven't used cooking oil but I do know used motor oil didn't work very well when I tried it. When I used it an ugly etched finish remained on the concrete. For some reason release agents are manufactured and this may be one reason why. For my project it didn't matter but I would think your post need to be top notch in the appearance department.

There were concrete posts installed on some ranches in my area 60 years ago with barbed wire attached that lasted several years. They tapered smaller toward the top with the top being pyramid shape. I was just a kid then and never got to see how those were poured and can only imagine the procedure.

Good luck with your fence building and keep us up to date on any progress.

 

[ultrarunner]

Concrete Posts are all everywhere in Germany/Austria... some are pre-war.

The ones by the highways do have problems from years of salt exposure... new ones are heavy galvanized or stainless rebar so as not to rust and pop the concrete.

 

[treman]

Have you considered buying pre-made plastic fence posts and pouring the concrete into them already in place. This will likely add slightly to the cost but the savings of not having to make castings or time involved in moving them around might be worth the extra cost. just a suggestion.