Most custom bookcases have adjustable shelves but it is not a hard and fast a rule. Adjustable shelving gives the user more storage and display options. Fixed shelves give a bookcase more strength.
I prefer to evenly space the shelves approximately 12-inched apart. We use shelf pins on our shelves and then drill an additional hole an inch up and down for a total of three pin holes. This gives each shelf and inch up and down in height adjustment. Installing the shelves this way ensures that I do not have a slew or shelf pin holes visible which I feel detracts from the aesthetics of the bookcase.
When thinking about shelf width keep in mind shelf sagging or deflection. Shelf sagging is measured in deflection, or the maximum distance in which the middle of the shelf bends as a result of weight [books] placed on the shelf.
The longer the shelf the more it will deflect, the shorter the shelf the stiffer it will be. Deflection of 1/4″ or less is a good goal when designing shelving.
The fronts of the bookcase shelves are typically reinforced with ¾” thick solid wood that can be milled with a profile or left square for a beefier look. Nosing can add a nice accent to the bookshelf edge.
Wider bookshelves or shelves that will receive a heavier load should have a wider nosing for additional support. Hardwood shelf nosing applied to shelves can help resist and prevent deflection.
Another solution for longer shelves or in this case a window seat is to consider using torsion box technology.
Bookcases typically mount to wall studs in the back and other locations where screws can be installed and hidden. Depending on the height of your bookcase it may be mounted to the floor and wall only or connected to the ceiling by crown molding.
On permanently installed units the room baseboard molding is incorporated around the bookcases. The room crown molding [if applicable] also wraps abound the custom bookcase and continues throughout the room.
What To Do About Exiting Carpeting?
Existing carpeting in a room can be handles in a few ways:
- The carpet can be cut to the profile of the new bookcase which would be installed on the sub-floor. Re-streching of the carpet and new tack strips would be required.
- Alternatively slots can be cut in the carpet and then strips installed to the sub-floor. These strips are then used to mount the cabinet to.
- Lastly, the bookcase can sit directly on the carpet. this is usually a good option when the bookcase is more like a piece of furniture and not connected to the ceiling with crown molding.
In all three cases I prefer to fasten the bookcase top and back panel to a wall stud to prevent tip over / crush hazard from small children climbing the shelves.
Photos: this pair of custom bookcases flank an opening from a living room into a kitchen. They were installed inside a condo. Their height was pre-determined by building codes. Fire suppression sprinklers are located in the sofit above.