Backing for cubby storage

[Anthony Whitesell]

I am in the process of building some french cleat mounted cubby storage boxes. The sides, top, and bottom are made of 3/4" plywood. I'm trying to decide what to use for the backing. I prefer to rabbet and recess the backs. I figure there are three options: hardboard (1/8" or 3/16"), 1/4 plywood, or 6.5mm (1/4") underlayment. What would your prefer?

[Clint Baxter]

I'd use 1/4" plywood, but it would be Baltic Birch for the additional strength.

Cllnt

[Anthony Whitesell]

That's what I have been pondering the most. What strength is the back providing?

There is only one cubbry per box, the boxes are 16" high, 16" deep, and of various widths. The french cleat will be screwed directly into the 3/4" carcass sides, not into the back. It may supply some anti-sag support to the bottom. I rabbet the back of the carcass to have the back provide a square reference when it is installed. But that does not require or provide any strength. I have used a drawer joint router bit (rabbet and dado corners) for the corner joints.

[Alan Bienlein]

Any of those that you have on hand will work just fine.

[Ole Anderson]

I would want something thicker than 1/4" to mount the cleat to, even if you are going into the 3/4" sides, which is somewhat problematic given the rabbit in the 3/4" sides needed for the backing. I would go with 1/2" ply.

[Bruce Wrenn]

Look at melamine coated hard board. It is used for tub surrounds. Choose a smooth pattern, not the tile look.