How much will a board-on-board (shadow board) fence reduce the wind load


I have had problems with a fence on one side of my garden because of wind in Montreal. The posts end up leaning away after a few years. Part of the problem might be how the posts were put in (perhaps not deep enough), but the wind is a big factor.

EDIT: Current fence design is 2m high with posts roughly every 15 feet, similar to the image below:
privacy fence image

I'm wondering if a board-on-board fence design (aka shadow board or shadow box fence) will help much. It seems that there's more wood involved in this design, and so it will cost more. I'm not sure how much it reduces the wind load, and I'm trying to get an idea of the cost/benefit of the design.

Here's an image to give you an idea of what I'm talking about:

shadow box or board-on-board design of fence

Best Answer

This is an interesting read:

The engineer says that there is no reduction in surface area, and the gap between boards isn't significant enough to significantly alter the air flow. He also says that in reality, there may be a minor reduction in the wind loading, but not enough to make it worthwhile.

You may want to consider a Louvred fence (angle board fence). However, these do not provide much privacy in the one direction, so you will want to angle the boards away from any nude sunbathing areas.

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