Wooden fence questions

[Frank J Warner]

Storm blew down a portion of a 30-year-old good-neighbor fence. 6 foot high, 4x4 redwood posts set in concrete, 2x4 rails, 1x6 dog-ear cedar panels. Surprised it lasted this long.

We're rebuilding the entire fence and have a couple of questions.

First, should we re-use the old post holes? We'd dig out the existing concrete and pour new, but the soil is sandy and not too stable to begin with. Digging the old concrete out will undoubtedly leave holes too big to fill economically unless we use cylindrical concrete forms. OTOH, moving the post holes over a few feet to undisturbed soil will create unsightly "short" panels at either end of the fence.

Second, does anybody recommend setting PT 4x4 posts in galvanized metal post brackets embedded into the concrete rather than directly into the concrete? I see those beefy brackets at HD and wonder if they would actually hold up in a windy environment like mine. The age of the old fence tells me that setting the posts directly into the concrete works just as well if not better.

-Frank

[John_B]

The houses I have lived in have clay soil which holds water very well. I usually backfilled the holes in which I stuck treated posts with gravel using the crushed marble sold in garden stores. I think this helps drain the water from the posts and thus prolongs their life, but of course I have never done any comparison tests. This also has the advantage that it does not require waiting for concrete to set and does not require tamping the fill soil to hold the post firmly.

[Chris Lewis]

According to Frank J Warner :

If you really can't move the posts, and want to stick with concrete, sonotube is the way to go, plus backfill.

[Tho, even if the hole is excessively wide, a pour of the same amount of concrete into the hole you'd have used for a "minimum" post hole will hold things up almost as well. Less likely to split too.]

Before pouring the concrete, bed the bottom few inches of the post in gravel, with a few inches of gravel below the post bottom.

[prevents rot, allows the water to drain out of the post.]

If you're burying the posts deep enough (ie: 4'+ in these parts), you may not need the concrete at all except on posts with severe tipping force (ie: gate posts).

I don't. The post brackets I'm aware of are really only suitable for deck posts, where the post is prevented from tipping by deck structure.

The brackets I'm familiar with won't stand up to trying to hold a freestanding 6' "solid" (ie: privacy) fence in strong winds. Too much leverage over too short a length of post. They'll eventually break. Or destroy the bottom of the post and the post will snap off.

[This includes the "deck spike" type of brackets (the top of the "spike" is a square "socket" for the post) as well as more traditional "saddle" brackets.]

[chibiabos]

Thanks, Chris.

-Frank