When remodelling a house it's almost always possible to fit in a new half bath — meaning a toilet and a sink. The real variable is the degree of convenience one can achieve when locating the new facilities in the space allowed. There are two benchmarks for laying out a washroom of any kind. The tightest space in which the fixture can be fitted and used is commonly called “adequate.” The normal space allotted for the function is what we would call “comfortable.”

Here are a few important dimensions to keep in mind when planning a new lav:

Anything tighter than “adequate” can be considered awkward or unpleasant, risking bumped elbows, shins, or bruised composure. Dimensions exceeding “comfortable” might feel luxurious or just right, depending on the home involved.

Granted, there are exceptions. Some fixtures require more space and others are designed for a squeezed-in lav.

It is also possible to further reduce the dimensions shown here by using a corner sink and some overlap of clearances.

If you are remodeling on a sailboat or your client has special needs, these dimensions will need to be modified. But for most of us the numbers given here should work out “just fine.”

—Dick Kawalek, a registered architect for more than 30 years, is the founder of Kawalek Architects, in Cleveland; rck@rktekt.com.