Building additions in historic commercial districts

In the previous two segments I discussed appropriate design for new infill and stand-alone buildings in historic commercial districts. In this third and final segment, I will focus on additions to older and historic buildings. These can include additions to the side, rear or top of buildings. With this type of new construction, it is very important that the new portion does not physically or visually damage the existing building. Any new addition should take design cues from the original building style, but there are two different yet appropriate ways to approach this in my opinion.

The first, and somewhat controversial, approach is to view an addition as merely a deferred expansion of the original. In that case, the addition should look largely like the original in material, size, height, massing, setback, and ornamentation. Many preservationists disagree with this approach, saying it jeopardizes the historic integrity of the original because it’s too hard to determine what is historic and what is new. But as mentioned previously, it is my opinion that only a trained professional needs to be able to distinguish the two, and usually the new materials themselves are just different enough to set them apart when viewed up close. Plus, adding a simple date stone can easily achieve this distinction.

The second approach, and one which I typically recommend, is to use the same massing, size, scale, proportions, etc., but simplify the materials so it’s relatively easy to determine what is new and old. In other words, if the original building has an ornate cornice, design the cornice on the new building the same height and depth, but without the degree of ornamentation as the original. With this approach, I almost always recommend that the new and old be divided by a modern connector, as is shown in the two examples below.

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