Sizing Up Glass Blocks

Glass block is indeed beautiful, but James Dulley’s Q&A; in Home Improvement (April 9) leaves out an important consideration, especially for “do-it-yourselfers.”

Ordinary glass and thermal glass can be made for virtually any size window, but glass blocks only come in certain sizes, and they cannot be cut to fit. While there are a variety of shapes and sizes that can be combined to fit different size window openings, careful layout is required to make sure the block will fit.

Often, a glass-block window will require both a new window frame and some alteration of the exact size of the window opening, which can mean minor (but important) structural work, stucco or siding work outside and drywall or plaster work inside. I suggest anyone interested in doing it themselves check out the possibilities (and consequences) with a glass-block supplier before proceeding. It’s always best to make sure the new will fit before buying it and tearing out the old.

The other consideration in planning a replacement glass-block window is to maintain the minium amount of ventilation area (openable windows) required by the governing building codes; generally, it’s 5% of the floor area of the room, but it makes sense to check with the local building department.

PAUL B. TURPIN

Los Angeles

Paul B. Turpin is a general contractor specializing in custom residential remodeling.