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Reference: Wood

Designing for Wood Movement, Part 1: The Wrong Way to Build a Tabletop or Panel

By Rain Noe - January 15, 2018

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Following this Urban Design Observation post, some Core77 readers have asked for a series on how to design for wood movement. I'll start here with some design basics. (And if you want to back up and understand the science behind why wood moves, check out this series on wood movement that we commissioned science writer Christie Nicholson to write.)

It can be helpful to learn from others' mistakes. Here's a video from a DIY website that shows you how to build a wooden tabletop to cover a folding banquet table:

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The builder here does not understand that this tabletop will not last, because she has violated a rule of wood movement: Boards will expand and contract along their width with seasonal changes in humidity. This expansion/contraction cannot be restrained, or the boards will crack and split. This is where she made the error:

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She has permanently glued and screwed the tabletop within that four-sided, mitered frame. Attaching the skirt to the long edges of the wide boards is no problem, but fastening them to the end grain of the wide boards, as shown in the photo above, is. The builder has constricted the wide boards' movement, and as they grow or shrink in width but are held in place by those end-caps, they will warp and split, making this a short-lived piece of furniture.

Here's another example of a design error:

Image by Popular Woodworking

Unless that center panel is plywood, which does not move, this type of design will fail. As the wood expands and contracts, this is what will happen:

Image by Popular Woodworking

And if those miters are securely fastened together so that they cannot separate at the joint, then the panel itself will warp and crack. Something's gotta give.

Next we'll show you another common "don't," then we'll get to the "do's."