At Renovation Design Group, we adopt the same theory promoted by Architect Sarah Susanka: "Build better, not bigger."

Susanka's "Not So Big" concept doesn't necessarily mean living in small houses, just in houses with the space that you need and comfortably use every day. There are too many houses with wasted space that homeowners rarely see, let alone use.

Her theory involves downsizing your project by one-third but keeping the same budget. The money you save on square footage is spent on fixtures and finishes to personalize your home, to make it more beautiful and to add character.

Susanka says making a house a home is more about quality than it is about quantity. It doesn't matter how big a house is if it doesn't function well.

Working within a smaller footprint, the design must be more creative and use subtle elements to make the most of the space. One space can comfortably serve multiple functions if it is designed properly and uses spatial concepts to distinguish it and add character.

Molding or trim is a tool that can be used to differentiate space in open floor plans, as well as to add personality to an area. If you have a kitchen and dining room sharing one space, you need a design element to set apart the room's multiple functions. A framed opening with distinctive trim will visually divide the space without closing it off.

Architects commonly used this technique in the early 20th century bungalows with beautifully cased openings and archways. The classic bungalow is a great example of doing more with less space.

In general, the wider the molding, the more prominent the transition between the spaces feels.

Susanka says one of the most regrettable trends in home design over the past few decades has been the decrease in the size of trim moldings used around windows and doors. The more substantial the exterior and interior trim, the more dramatic the finished look, feel and personality of the home will be.

Casing (or trim work) in a house can get expensive. Standard crown molding professionally installed costs around $8-$12 a foot or about $300-$500 per 10-by10-ft. room. Crown moldings range in size from 11/2 to 20 inches wide; the proper selection depends on the height of the ceiling, the size of the room and the home's architectural style. In an average home, crown moldings are about 4-5 inches in height.

There is an almost unlimited variety of decorative molding styles. They can be everything from simple concave design to layers of straight-edged grooves, to patterns of rosettes, vines, ovals, squares, columns or cornices and more.

Custom moldings can be ordered in almost any size and shape.

Along with the variety of design, you have a variety of materials as well. Historically, trim was made of natural wood, with pine being the most common and least expensive.

Today, however, casing and molding is also available in MDF (medium density fiberboard, a manmade composite material using wood fiber) and molded polyurethane, which can reduce the cost and maintenance associated with both interior and exterior details.

You can save money installing casing and trim yourself, but this type of work can get a little tricky. Unless you're handy with a compound miter saw and have a mind for geometry, you're better off leaving installation to the pros.

Adding decorative molding is definitely one of those smaller projects that can have a dramatic impact. Just plan your projects accordingly. You don't want to do the trim work out of sequence with your other remodeling projects.

If you are planning a more extensive renovation, consider building a little smaller than you first planned.

You could do a "Not So Big" remodel and use the leftover budget to add a little more personality with some high-quality trim work.

Architects Ann Robinson and Annie V. Schwemmer are the founders of Renovation Design Group, www.renovationdesigngroup.com, a local firm specializing in home remodels.