Beadboard or T&G Backs for Built-ins: Proper Methods?

[Jim Kaczmark]

I'm planning for a large set of built in cabinets to go on each side of my fireplace. Even after breaking the whole cabinet on each side into smaller sub-parts (plywood boxes), I'll be left with pretty sizeable backs on them... largest back will be 52" wide by 41" tall. Question is two part:

1) In general is there a proper way to install real beadboard or tongue & groove in this situation?

2) Racking of the cabinet out of square is of concern to me given their size... would the beadboard / T&G somehow be stable enough given the answers to the first question to prevent racking?

Some additional notes: I say "real" beadboard because each board will be milled... will not be using simulated beadboard milled into a sheet of sheet stock. Same goes for the T&G. This is because I will be making it out of rustic knotty alder and milling a groove through a knot just wouldn't look right.

My current idea will be to dado a slot say one inch from the back of the cabinet into which I'll sit the ends of the beadboard / T&G. Then behind this, on the very back edge of the carcas sides, bottom & top mill a rabbit into which I'll glue & pin a 1/4" or 1/2" piece of sheetstock to keep things square. (Is 1/2" inch overkill in this situation?)

Now the "meat" of this posting: Installing the beadboard / T&G itself... correct methods? Should I simply, place board by board the beadboard / T&G into the dado's, then let the entire panel of boards freely float within the dado's? Should I pin one side of each board into the dado, then let the other side of the board float to accomodate envionment changes? On the back side of the cabinet, should I place a line of silicone seal along the entire edge where the T&G / beadboard enters the dado's to avoid any rattling... would the silicone seal be flexible enough to accomodate the wood changes? Other ideas / concerns / comments?

One section of the cabinet will contain a TV... below it in the base cabinet will be the electronics. A single speaker (sound bar) will be placed on the shelf above the TV, and a subwoofer will be placed in the base cabinet. To avoid vibrations, I will actually cut a hole in the bottom of one side of the base cabinet bottom so I can sit the subwoofer directly on the concrete below the cabinets.

Thanks in advance for your comments!
Jim

[Rod Sheridan]

Hi Jim, racking shouldn't be a problem with built in cabinets, once you attach them to the walls.

When I use a bead board back, I install the boards into a rebate, beginning with the center board.

I nail each board on with one nail top and bottom about 1/2" from the tongue.

If it's dry at your house now, leave enough gap between the boards to take care of expansion during the humid weather. For my house/climate. 1/8" is enough for a 3" board.

Regards, Rod.

[Jim Kaczmark]

Rod,
Thanks for your reply... I hadn't considered a simple rebate with nails... given the proximity to a subwoofer, I think I'd worry a bit too much about vibrations & rattling.

I'll follow your gap between the boards recommendation through.
Jim

[Larry Edgerton]

Hi Jim, racking shouldn't be a problem with built in cabinets, once you attach them to the walls.

When I use a bead board back, I install the boards into a rebate, beginning with the center board.

I nail each board on with one nail top and bottom about 1/2" from the tongue.

If it's dry at your house now, leave enough gap between the boards to take care of expansion during the humid weather. For my house/climate. 1/8" is enough for a 3" board.

Regards, Rod.

Ditto. I almost always make my own T&G for these situations, so I just make one for the center with two tongues, and I work it out so they are the finishers are the same size. I make two a little extra wide for the ends with no finished edge on the side that gets trimmed in case I am a little off.

I hate adjustable shelves and seldom use them, but even when I do I insist on one in the middle somewhere that is fixed, and use it for a nailer as well.

I don't leave as much room as Rod here, in fact I do not leave any. I will jamb them a lot tighter in the summer, and I make my side rabbits around a half and leave a 1/4 gap for expansion. I have not had any callbacks.

I have not had any problems with racking and I nail just as Rod has described.