Size of fence posts?

[911 Rod]

Fence advice needed please.
My son and his neighbor are splitting the cost on a wooden fence.
100' x 6'. No lattice.
Neighbour wants 6" posts so the fence will last 100 years he says. (Old fart)
I think it will be gaudy and a waste of money instead of 4".
It's isolated from the wind, but there are train tracks be hind the houses.
4" or 6" posts?

[Scott Douglas]

I would think with the cost of wood these days that for 6" posts you could easily put in a cinder block wall.

[KFC911]

They're gonna use pressure treated ground contact posts in concrete .... right?

I'd do 6" ... every what ... 8' ... cost difference is not bigly ... divided by two.... meh.

Easy decision ... I've used 4" up until now ... and plan a lot more....real soon...

I'll prolly use 4"

6 is better tho' ... 4 is good enough for me.

HTH .... LOL

I dunno???

[IROC]

My girlfriend's fence has 4" x 6" posts - just to throw a wrench in the discussion.

[KFC911]

Originally Posted by IROC

My girlfriend's fence has 4" x 6" posts - just to throw a wrench in the discussion.

That's what Ima gonna use ... she must be brilliant

[unclebilly]

What type of livestock is he keeping in?

We build barbed wire fences all the time. The corner posts are 5.25 or 6” and the normal posts are 3.25 or 4.25… every 16.5’.

My fences see far more load than the fence in an urban backyard ever will. In the summer cows are running on them constantly trying to get to the grass on the other side. In the winter, the tensile load of the wire from thermal contraction pulls them incredibly tight. A good fence lasts 40+ years. I just replaced one with old split cedar posts that was about 100 years old.

4” is fine especially with an 8’ spacing. The fence will get torn down for other reasons long before it wears out. Stop overthinking this stuff.

[craigster59]

I used these on my last fence. That baby is still standing 25 years later...

https://www.homedepot.com/p/Simpson-Strong-Tie-PGT2-12-Gauge-ZMAX-Galvanized-Pipe-Grip-Tie-for-2-in-Pipe-2-3-8-in-Outside-Diameter-PGT2Z-R/100374928#overlay

[Seahawk]

What type of wooden fence? Rail, solid, etc.

100ft is going to be 14/15 posts depending. Adding two feet to every pole is essentially 30 extra feet of post baked into the price: At the local Tractor supply, 6'5" x 3.5" are $12.00 a piece.

I'd go 6 feet depending on the style of the fence, 'cause...

[KFC911]

I need to drop by Tractor Supply

Thanks!

[911 Rod]

The type of fence where the boards stagger from one side to the other.
He and my son are adamant that it will be a better fence with 6" posts.
Maybe the fence guy has extra 6" ones and wants to get rid of them.
The quote is for $6500.
I guess I should just stay out of it and mind my own business

[Seahawk]

Originally Posted by 911 Rod

The quote is for $6500.

Labor as well?

Workable.

[911 Rod]

Originally Posted by Seahawk

Labor as well?

Workable.

Just + tax

[p911dad]

We have approx. 560' of property line fenced with treated posts, 6" X 8', in concrete with 3 cross beams, posts 10' on center, plus corners and maybe a gate or two. Over-laid with 3' steel mesh to keep pets in. Around here they last maybe 5 to 7 years, the idea is to replace them as they go so you don't have a big job all at once. Our yard guy currently charges $150. per post installed, including the post and materials. The cross beams last a long time. I don't recommend using the big box stores for these, crappy quality.

[Tidybuoy]

I just finished building a 6' fence and I used 4x4 treated posts.

My Opinion:
I used 4x4 posts but I spaced 7' apart vs. the typical 8'. It's pretty sturdy and the fence I built 25 years ago (identical) is still just as strong as new. However, my fences are 60' long and connect to other fences at 90 degrees so that adds some stregnth.

I would think that if you are going to space at 8', a 6x6 would add strength.

My lumber company recommended using "treated" lumber for the posts because the redwood these days is grown faster and does not have the anti-bug/rot properties that older lumber has.

[MikeSid]

What Tidybuoy said.

The dimension of the posts is not the failure point. Over time, stringers to which the pickets are nailed may sag if they span 8 feet. Shortening the dimension of each fence panel to 7 feet will improve longevity far better than increasing the diameter of the posts.

And no wooden fence made of conventional materials is going to last 100 years.

[masraum]

I'm wondering, what's more useful, a thicker/fatter post or a longer post that goes deeper into the ground.

In the greater Houston area, most fences seem to fail by falling over, not due to breaking, but due to the ground being soft and falling over likely due to the ground becoming saturated and sloppy.

[911 Rod]

We also have ground frost here

[Tobra]

4", 6" is stupid

[oldE]

I would also consider the moisture level in the ground. The other week I replaced a 4x4 pressure treated post which had rotted through at ground level due to wet conditions at that location. It lasted about 25 years.

Best
Les

[David]

4" is plenty but I go 7' between posts rather than 8'. Adds to cost but helps when a hurricane shows up. We also run 3 horizontal 2x4's rather than 2 and a 1x6 treated rot board at the bottom.