Need input 8ft back yard privacy fence....

[firebird1999us]

For the fence itself I’ll just be going with 8ft treated dog eared pickets mounted with stainless, star drive screws... I may potentially cut them down to 7.5’ to lose the dog ear top or based on not needing exactly 8ft.

I’d be using 4”x4” boards throughout and am trying to figure out adequate depth. The dimensions are 50x70’ and I was going to to run a post about every 6’. I was also going to add diagonal bracing outside the fence at maybe a 30degree angle since it’s so tall. I’d probably do 4”x6” or potentially 6”x6” at the corners. This is on a totally flat, graded back yard.

Traditionally my family has done wood/railed fencing for livestock and we just dug a hole and plopped some cement in the ground. I’ve seen the various foams out and have reservations. I’m not looking to live here forever but the previous fence put in by the builder did not hold up well. The posts are all oddly spaced and the once’s that are cemented look like they’re about to rot apart. Is there a specific type of ground treated Post I should look for... or are the ones at the Lowes/Home Depot/wherever all the same?

 

[Mongo68]

Just had a fence done and they used these metal shaped posts instead of wood. Ive seen them at Lowes or HD. 2x8 pressure treated longways at the bottom...

 

[Richard Cranium]

8 foot will catch a lot of wind, I used to have an 8 foot fence in my back yard around our pool, The wind would blow part of it down every year, either it would walk the posts out of the ground (2 feet down) or break the 4x6 post off at the ground. I replaced it with chain link. No problem any more.

 

[pattenp]

Post should be treated for ground contact and have a 40 year rating.

 

[CraigStu]

This was just one contractor's opinion when I was repositioning a fence after he had added an extra garage bay for me. He said that the latest was to just put the post into the ground and tamp the soil down around it. His impression was that the usual concrete formed a water tight bucket around and under the post which retained the water that would seep into it and hasten the post rotting. He felt that plain old dirt let the water migrate away from the post better.

 

[strutaeng]

There's a rule of thumb that says 1/3 to 1/2 of the fence post above the ground should be buried. 1/2 seems overkill to me for 8' fence.

I live in an area where rock is below 12-18" of the grade. I built 2 small front fence segments 8' high and had to do a sort of footing on each post. I'm using 2 3/8 galvanized posts. I just held down the concrete so you don't see it.

Another segment I rebuilt I set the new metal posts in a continuous strip concrete footing along the fence where the original fence was set in wood posts. The wood posts were gone, leaving square holes. I cleaned the holes and used rapid cement for the new round posts, approximately 2' below. That worked nicely because I didn't have to dig, just clean the existing holes.

I looked on line and there's not much information on 8' fence. I would go down 24-32".

Fence posts come in 8', 10' and 11' around here at the home centers.

 

[Captain Spaulding]

Typical box store treated 4X4s are nothing but garbage. They are not treated well enough to withstand burial, and 9 out of 10 will twist or warp badly. Even if you get ground contact treated posts, you still have the warping. There has to be a better option for posts.

 

[firebird1999us]

Typical box store treated 4X4s are nothing but garbage. They are not treated well enough to withstand burial, and 9 out of 10 will twist or warp badly. Even if you get ground contact treated posts, you still have the warping. There has to be a better option for posts.

That’s exactly why I’m here! The forumite that posted 40 year ground rated above is what I was after - going to start calling around. I’m fine getting dog ears from there though. I want something easily replaceable and if mounted right they seem to hold up well without issues.

 

[firebird1999us]

Here’s a stupid question - and I’m sure here obscenely expensive - has anyone used any sort of composite for fence posts? I’m probably talking about 25 posts at most..

 

[strutaeng]

I got quoted for some 3x3x1/4 steel tubes for my other fence for 14 posts, i think 12' long each for something like $1,200 from my local steel supplier.

I would imagine composites are like 3-5x times higher than steel, if not more.

 

[ddurrett896]

Here’s a stupid question - and I’m sure here obscenely expensive - has anyone used any sort of composite for fence posts? I’m probably talking about 25 posts at most..

Chain link poles + OZ post fence brackets

Scroll down to bottom...

http://www.hooverfence.com/catalog/hardware/oz-post/fence-brackets.htm

 

[nmmiles]

I built the exact fence you are describing this past summer. 8ft dog ears, 4x4 treated posts 8ft OC, I used 2x4x8 stringers across the post 2ft from the ground and one at the top of the post. I burried the posts about 24-30 inches deep, no concrete, and it wasnt enough. The fence is so heavy it leaned in and out horribly. I went back, dug them all up and added concrete. Zero change. Looking back I would have went deeper, but I still think I would need to have angled bracing on the back side. I also suggest having 3 stringers between the post. That will greatly help the rigidity for very little cost.

 

[dmark]

+1 I would do this if I did another fence.
I had a 6' high shadow-box fence professionally installed in 2010. 4x4 pressure treated posts were set in concrete. 2 years later hurricane Sandy took down 6 panels snapping the posts. The posts had rotted in the cement. (no more copper sulfate or creosote used) I replaced all 17 posts packing them in pea gravel and soil for the top 2 inches. I tamped them down with a heavy steel pry bar. 2' deep for the 4x4 fence posts and 3' deep for the driveway gate sections. (I wish I used 6x6 here)
I like to say I earned my PHD (post hole digger; clamshell shovel after work for weeks)
2018 still good but today I would do steel poles in cement with brackets for the panels.

Chain link poles + OZ post fence brackets

Scroll down to bottom...

http://www.hooverfence.com/catalog/hardware/oz-post/fence-brackets.htm

 

[firebird1999us]

Chain link poles + OZ post fence brackets

Scroll down to bottom...

http://www.hooverfence.com/catalog/hardware/oz-post/fence-brackets.htm

I was actually considering using galvanized posts as bracing from an angle about 3 ft behind the fence on 2 sides. I’ve seen those pics and was intrigued by it. Do you need to cement those in or use one of the tools that fits over top and hammer it down into the ground?

 

[m32825]

Look around for a company that supplies the dock building industry, like these guys:

http://southernpinelumber.com/products/piling/


The big box stores sell lumber rated for ground contact, as in: "laying on top of the ground". Which is what your fence will be doing after a few years if you attach it to that product!

 

[JRC3]

This was just one contractor's opinion when I was repositioning a fence after he had added an extra garage bay for me. He said that the latest was to just put the post into the ground and tamp the soil down around it. His impression was that the usual concrete formed a water tight bucket around and under the post which retained the water that would seep into it and hasten the post rotting. He felt that plain old dirt let the water migrate away from the post better.

That's why gravel goes on the bottom. Concrete increases the girth and contact to the earth. A bigger footprint is good.

 

[EOC_Jason]

I think the biggest problem is people don't slope the soil or concrete away from the post. Instead it ends up being a recessed hole because they didn't account for the soil settling. (Or they didn't put any soil on top and just have the recessed hole with concrete.)

Instead the fence line tends to be the lowest point between properties and you end up with a lot of standing water till it evaporates.

I would agree with JRC3's post... You need to have the concrete slope away, or at the very least the soil.

You can get copper sulfate in a can and maybe treat the posts some more before setting?

Maybe also check your local independent lumber yard, see if they have anything they would recommend.

 

[shanker]

I'm in the process of rebuilding my fence after Hurricane Harvey blew them all over. I learned that putting 4x4 posts 40" in the ground set in cement was adequate, as the posts snapped at the ground (we had 130mph winds at my house, about 20 miles south of the southern eye wall).

This time I'm going to use 4x4 posts (MAYBE 4x6 posts) on 6' centers and shadow box the side fence that takes the brunt of wind's since it faces the street. I'm also going to set steel pipe (old oil field pipe) as corner posts at about 6 feet deep for additional structural support. I'm hoping that shadowboxing it will reduce the wind drag even though I'm going to place the planks so that you can't see thru it going down the street.

 

[lakeroadster]

Here's the CCA Ratings you want to have for the wooden posts.. Since your not planning to stay there forever.. wood should be fine, set the way JRC3's diagram shows.

We did about 500 feet of privacy fence that way back in Ohio. Rented a Toro self propelled track style unit with an auger. Worked pretty sweet.

What is CCA-treated wood? Chromated Copper Arsenate (CCA). CCA is a chemical preservative comprised of arsenic, chromium, and copper

 

[Mongo68]

https://www.lowes.com/pd/Master-Hal...-5-in-x-7-5-ft-Silver-Steel-Line-Post/3434930

 

[Lelandwelds]

Steel posts with homemade clips. Weld top closed or fill with cement. Three each 2 X 8 lateral. SS fasteners. Easily replaceable sacrificial bottom spacer to raise dog ear above ground contact.

Last decades even without galvanizing or powder paint.

 

[sixty4]

You guys are lucky we only get a 6' from grade to top of fence here.

 

[bullnerd]

"I tamped them down with a heavy steel pry bar"

This, Use the mushroom head of a root bar or what ever they call them and tamp as you go, not just once the hole is filled.

Isn't there a big write up about why the posts rot at the surface? Concrete or not.

No concrete in my opinion.

The 6' centers sounds good for resisting the wind load.

 

[strutaeng]

You guys are lucky we only get a 6' from grade to top of fence here.

We are allowed 9 feet. Anything higher needs to be in the setbacks. Higher end neighborhoods are all 8 feet for new fencing and rebuilds. Everywhere else is 6 ft mostly. Taller fence = more money.

 

[ddurrett896]

I was actually considering using galvanized posts as bracing from an angle about 3 ft behind the fence on 2 sides. I’ve seen those pics and was intrigued by it. Do you need to cement those in or use one of the tools that fits over top and hammer it down into the ground?

I did a 6' fence and used 8' poles, with about 30" below the ground. 5 years now and standing strong.

 

[firebird1999us]

Anyone ever use these:

http://www.postprotector.com