Is any concrete necessary for non-structural post?
pjpfeiff
| Posted in General Questions on
I’m planning to put up a 4×4 post which stands 8 ft above ground with 3 ft in the ground (so 11 ft of post total). It is only intended to be used for hanging a string of lights around the patio, but clearly if nothing else it needs to take the load of someone leaning on it and remain plumb to the eye. I think I would call the soil a loam (it’s really nice for gardening, definitely not sandy and definitely not hard clay). Is any concrete at all necessary?
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Replies
Paul,
No, and it will last longer without it. Over size the hole a bit and fill it with clear-crushed 3/4" gravel, tamping as you go. That will allow the post to dry.
Utility poles aren’t set in concrete, but they are usually set quite a bit deeper (and they’re also quite a bit taller). You’ll be fine setting your post in the ground directly.
I would recommend getting a post rated for heavy duty (or “critical”) ground contact with the 0.6 pressure treatment level. This will last longer. I’d also recommend setting a 12 foot post for 9 feet above ground. You want to think about the height of your lighting wire at the bottom of the sag of the span, so with 8 foot poles you might find your wire gets down around 7 feet. 8 feet is a safer clearance. 10 foot clearance is the usual recommendation over grade for electrical wiring assuming no vehicular traffic.
Bill
You don't have to since it's not structural but it's better to set your post below the frost line otherwise it will move. So either you dig down or you put your post on a concrete or steel pile. Helical steel piles are a good solution for that sort of problem and they aren't that expensive.
Paul,
I'm planning to do something similar, but to avoid digging, I'm putting my posts in fiberglass whiskey barrel planters. Posts will be set in ~1 foot of concrete in a 12" sonotube before they go into the planters (you could just pour directly into the planter, but I want the posts to be removable in the future).
If you end up digging, the commenters above all gave great advice.
Jay,
That's a good idea. Posts on their own often look sort of lost. What are you putting in the planters?
Thanks, everyone!