A recent tour of townhouses in the Virginia suburbs brought home certain truths about the building industry. Most change is slow and incremental, but occasionally you see something that lives up to the hype — it really is new and different. And the most interesting designs are nearly always in the smaller houses because every square foot must be usable space.

Camberley Homes’ Lakeshore townhouse model in its Boulevard at Brambleton project in Loudoun County is unusual.

With 1,950 square feet, the $369,900 base-priced Lakeshore is small by Washington standards. Its 20-foot-wide by 38-foot-long footprint is typical for a townhouse in this area. What differentiates this model from the competition is its floor plan configuration, a consequence of the highly original way in which architect Smita Anand of the KTGY Group in Tysons Corner joined the five to seven units of each townhouse cluster.

In a typical townhouse development, the six to eight units of each cluster are lined up in a row. Here, the units in the middle of each cluster are aligned as you might expect. But the two units at each end are offset so that each one has windows on three sides — a common feature of single-family houses but unheard of in townhouses.

A second advantage of this unusual clustering is that the stairs in each end unit can be located at one end of the house instead of in the middle, as they are in most townhouses. This frees up more useable space on each floor and more flexibility in room arrangements.

In moving the stairs to the end of the third floor, Anand was able to make both secondary bedrooms a good size (in a townhouse of this width you usually get one good-sized secondary bedroom and one small one that is invariably furnished as a home office).

On the second floor, the stair location allowed the architect to move the powder room out of the main living area and into the hallway so that it doesn’t open directly onto the living room, dining room or kitchen, an arrangement that many townhouse owners gripe about. This practical detail will escape most first-time visitors, however, because they will be focused on the living, dining and kitchen area, attributing the very different feel of this space to the abundance of windows on three sides of the room. But, in fact, the space feels different because it is nearly square in shape and each function can be adjacent to the other two and not stretched out across the entire floor as they are in most new townhouses.

No matter where you are sitting — at the kitchen island, the dining table or relaxing on the sofa — you can easily converse with another household member and talk over the day’s events. For a parent with small children who need constant supervision, every corner is in full view. Of course, the windows do enhance the space and make it “live large,” builderspeak for a space that feels bigger than it actually is.

How was Anand and her team at KTGY able to move so far outside the box with this project? Home builders usually put their architects on a short leash. But in this case, Camberley needed a townhouse design that would fit into an approved site plan that had been created for a different type of housing unit that the firm concluded would not sell at this location. Because the lots in the approved site plan were unusually deep, the architects were able to shift the townhouses around to form an unusual U-shaped cluster, and this opened up new possibilities for individual units. The process, Anand said, was like “taking pieces of a puzzle and joining them together differently.”

The smallest townhouse that I toured is the most efficient floor plan I have ever seen. Ryland Homes’ 1,800-square-foot, $304,990 Brighton II at its Summerwalk condominium project in the Stone Ridge development in Loudoun has no odd corners, tiny closets or skimpy storage in the kitchen and bathrooms. Of perhaps greater significance to potential buyers, each space in this three-level, three-bedroom, 21 / 2-bath townhouse feels like its counterpart in a larger single-family home.

When you factor in the constraints under which the architect, Daniel Ball of Daniel Ball and Associates in Columbia, was working, his design is even more impressive.

The Brighton II is a back-to-back townhouse. In this type of clustering, two rows of townhouses are joined at the back so that each unit has shared walls on three sides and only one end has windows. In this particular iteration, the ground floor of each pair of back-to-back units has two separate one-car garages on the front. The three levels above the garages on the front belong to the Brighton II. The three levels at the back, plus a ground floor rec room that backs onto the garage, belong to the somewhat larger Chatham II.

Two things differentiate Ball’s Brighton II design from most back-to-back townhouses: the 23-by-27-foot footprint and the rear stair location. The footprint is unusually wide for this price range, and it allows for reasonably sized rooms. With the 27-foot depth, the stairs and space around the stairs to get from one level to the next can be moved to the rear wall where the architect was able to tuck in a powder room, a mechanical closet for heating and cooling equipment, and a laundry closet with a washer and dryer.

As with KTGY’s project at Brambleton, which also has the stairs at one end, the space on the main living level is nearly square so that the functional areas are adjacent to each other and two people anywhere in the room can easily converse.

Katherine Salant has an architecture degree from Harvard. A native Washingtonian, she grew up in Fairfax County and now lives in Ann Arbor, Mich. If you have questions or column ideas, she can be contacted at salanthousewatch@gmail.com or www.katherinesalant.com.