Adding additions to houses is a time-honored tradition, not only here in America, but throughout the world over thousands of years. It was historically easier to add to an existing house, rather than to sell it and move to a larger home. Most people (and successive families) in history tended to stay put and enlarge their homes as needed. There are several approaches we can take when deciding to add an addition to a period home.
When adding to an existing house, the additions generally should be smaller and deferential to the main house, but utilizing the same or similar materials and details, so the additions look like they “belong.”
When an addition is smaller than the original house, one can continue the same exact design of the main house, in massing, roof pitch, materials, detailing, etc. In this case the desire is usually to design the addition to be deferential to the main house, which should still be the center of attention, but appear as if it was either built as part of the original house, or clearly appearing to have been built as an extension of the house, at a later date. In the second case, the model “Big House, Little House, Back House, Barn”, used for centuries for rural farm houses when the main house ended up linking to the barn, can act as the model for tying various components of a house, so it looks like it was carefully planned and built over time. Sometimes all of the design details can match exactly, and other times, the additions can be designed with different materials on purpose, to emphasize that the house was, and is, still a work in progress.
Often, when a house has a very unique and clearly defined style (rather than just a generic “colonial” house), the desire is to continue those details with the addition. The New England Saltbox house, for example, may have started as a cape, then was expanded to a full second floor, and as the family grew, a kitchen and bedroom were added to the back, with the roof maintaining its pitch down to the back wall. This gave the house its unique saltbox shape, and appears to be all built at one time, when in fact, it probably evolved to this shape over time.
If one is lucky enough to find the original construction drawings, these details are an invaluable source to match the new addition’s details to the original house.
Even when designing a new house, especially if it is large, it may be desirable to design the home to appear as if it grew over time, that sympathetic additions were added. This approach can minimize the appearance of an overly large house by breaking the massing of the house into smaller units.
Many of Royal Barry Wills’ early to mid-20th century colonial revival capes and colonials adopted this technique, so large houses can appear more like a rambling “village” rather than a single giant manor house (or McMansion, natch). By carefully designing the house in this manner, the house will not overwhelm, but rather feel more relatable to both its occupants and the public and feel right at home in its immediate environment.
This Royal Barry wills rambling cape cod house was actually built all at once, but it clearly illustrates how the “additions” could have been “added” to the main house over time. Reorienting blocks of addition can add visual variety, if the space allows. The roof pitch, siding materials, window types, etc. all match or are closely related to unify the design.
If an original period house has the original construction documents, the architect’s job will be much easier, as the period details can be replicated to provide a seamless transition from old to new. In the case (most cases) where these drawings do not exist, the architect can photograph and field measure the appropriate details of the original house and provide the period correct drawings of the new addition for the builder to replicate.
It is my job as a traditional residential architect to fully understand the design language of the historic home, and utilize my knowledge of period construction to design an addition that is both sympathetic to the main house in style and detailing as well as practical and functional for the homeowner.