# Freestanding Fence Base Size

I'm trying to build a free-standing fence or barrier that will sit on top of concrete similar to this picture:

The fence I want to build is a bit taller - 6-8ft. Two questions:

• How wide does the "feet" of the fence have to be to keep it from falling over in the wind?

• I'm thinking about putting support braces in the photo like the picture - do they have to be on both sides of the fence and what size and height does the brace have to be?

• Why do you not want to pound a few bolts into the concrete to provide proper stability? Heck, even bolting the end sections to your house or whatever structure meets the fence would take care of the problem. Commented Aug 24, 2016 at 14:55
• @CarlWitthoft - I rent, and the landlord won't put in a fence. Back is exposed to a condo. Commented Aug 25, 2016 at 0:13

YES! You can build it exactly like the picture shows but with feet (on both sides) proportionally larger depending on final height and wind resistance required.

To ask what is wide enough "to keep it from falling over in the wind" is not answerable because it is too subjective; the right (wrong?) wind speed could take down almost anything. It would depend on materials used, method of construction, and wind load you would expect it to withstand. You could certainly build it with the knowledge that you do not know what conditions would tip it, and move it to a safe location whenever there is significant wind ("significant wind", again subjective).

If you were to finalize the construction details (material, height, width, design details) a civil or structural engineer might be able to give you a ballpark wind shear resistance number.

Freestanding fences normally look like this

Note:

• Heavy concrete feet.
• Very low wind-resistance wire-mesh panels.

I don't think you can replicate this with a wooden fence, even a picket fence is much more affected by wind.

• This is hardly an answer. It's not terrible difficult to calculate the C.G. of the picket fence and the tilt angle at which it'll spill enough wind. Commented Aug 24, 2016 at 14:53

build an A-frame fence: two panels leaning against each other, hinged or interlocking at the top. Make sure to include a cross bar near the bottom to keep the bottom of the panels from splaying outwards. Place sandbags on the cross bars to make it even sturdier. Both sides do not have to be fence. Use braced legs on one side or modify as desired.

Free standing this high sounds NUTS to me. Even with supports on both sides sevaral feet long it will blow over with a winter storm in every place I have lived. If you never have wind it would still require supports on both sides. This looks like a drive way to me and it is probably hinged to open.