wooden fence post install method

[zzap]

This topic has been adressed before, but I wasn't able to really find an answer.

Purpose of Post:
To determine the best method for setting posts for a wood fence: embedded in concrete vs. post base atop concrete pier etc.

Fence Description:
6x6 posts, 6ft high, 10ft long (i.e. a short bit of fence)
The soil is variable and generally shallow in the area (don't have specific measurements for the proposed fence location); therefore, a concrete footing will probably be necessary.

My Suggestions:
I've read much about posts rotting in concrete, even if the posts are pressure treated to "ground contact" rating with CCA or equivalent. I haven't seen much about post bases appropriate for a non-top-supported structure like a fence. Though it seems to me that a HSS sleeve attached via a welded base plate with anchor bolts to a concrete pier with a 2" gap between wood and concrete and allowance for drainage (drain hole in sleeve, sloped concrete top) might work; or an off-the shelf equivalent. The other idea is to imbed the post in concrete with a "post protector"

http://www.postprotector.com/.

The latter seems like a pretty good solution, although if not properly installed and sealed it will hold the water against the wood like a son-of-a-gun.

Question:
Please provide comment, towards determining the best solution.

Purpose of Fence:
I will have to digress into some electrical stuff here, skip if not interested. The purpose of the fence segment is to upgrade an existing substation fence installation. In order to avoid transfering dangerous electrical potentials beyond the substation in the event of a fault, I'm looking at removing a section of chain link fence and replacing it with a non-conductive section of fence, hence the wood. The idea is to electrically isolate the "station" fence (surrounding the equipment) from the attached "boundary" fence (extends beyond the station area). This is not an uncommon approach.

Existing Fence particulars:
An existing section of chain link fence shall be removed and replaced with a section of wood fence. The posts of the existing fence are imbedded in a continuous 8" wide concrete footing (foundation wall). The concrete "wall" will have to be removed for the same reasons: because it is electrically (semi)conductive.

Thanks in advance!

 

[PatBethea]

Pack sand and gravel around the fence post. This allows for drainage away from the wood.

 

[RARWOOD]

I deal with simialir problems with pinic shelters using posts and beam construction. Typically the posts are embedded into the ground or concrete piers that are embedded. This is done to provide moment resistance at the post base to laterally brace the structure.

Most customers however prefer a system where they can pour the footings and slap first setting the fianl shelter on top. The problem with this approach is developing moment resistance either at the top or bottom of the post to provide bracing to resist wind load.

Usually the problem with the above approach is the amount of steel required to make the structure rigid enough is expensive and unsightly. So in most cases steel tube columns are used.

With your fence your load requirements are lower so you maybe able to develop a post base that is not so expensive. You should contact Simpson Strong-Tie to see if they have a reccomendation for using their standard parts or will do a custom base that will meet your needs. I reccomend contacting Simponsbecause I work for a company that distributes Simposn Hangers.

A final note regarding the use of embeded wood posts. I would reccomend only using CCA or ACQ treated Southern Pine Posts. Use posts that are treated to the FDN standards developed for wood foundations, if they are available.

 

[SteveWag]

The wooden fence is pretty conductive, as things go. I would much rather have a well grounded chain link fence for protection. If the wooden fence is to be placed in the same location as the chain link fence, just fasten wood to the exterior of the chain, using plack plastic tye-wrap fasteners.

Steve Wagner

 

[rday]

I would go with gravel as suggested by PatBethea. Simple, cheap and effective for a 6 ft fence.

To my knowledge, all the Simpson post bases mention the lack of rotational resistance in non-top supported conditions.

 

[zzap]

Thanks to all for your posts.

C