Another house style with a great name. Saltbox houses originated in the New England colonial period and remain popular here even today. The very distinctive elongated saltbox roof creates a unique look and some unique heating and ice issues as well. Owners of saltbox houses seem to call for energy audits about the same set of problems as Ranch houses and Cape Cods. It’s as if builders married the issues of both houses.
Usually there are icicle and ice dam problems and cold second floor rooms. Why does such a venerable style as the saltbox suffer from problems that ought to be commonly dealt with in New England?
What Are Saltbox Houses?
Saltbox houses are a traditional Colonial-style native to New England and common to this day. Its defining characteristic is a long sloped saltbox roof in the rear of the house. There are usually two stories in the front and one story in the back.
Older saltbox houses are post and beam structures, though is is era specific rather than a feature of the style. Some saltboxes date to the 1600s. Modern saltboxes are platform framed and their interior framing looks like a Colonial in front and a kneewall Cape Cod in the rear.
The chimneys are centrally located with flat gable ends and a flat symmetrical face. The distinctive saltbox roof developed when colonial-era farmers made permanent structures from temporary lean-tos constructed on the rear of their Colonial farmhouses. This photo shows a barn with an attached lean-to, precursor to the saltbox roof design:
Saltbox Houses – Advantages
Use of Space – The main advantage of a saltbox house over, say, a comparable sized Cape is extended second story storage. Where a Cape Cod would have truncated kneewall storage spaces, the extended saltbox roof pitch allows reasonable access to a larger segment of the second floor footprint. The style also enjoys very good head room and living space on the second floor, as the front half is a fully framed floor.
Saltbox Houses – Disadvantages
As I always say, there has to be some disadvantages, otherwise everyone would have a saltbox.
Ice – The long, sloping saltbox roof line is a distinctive, elegant feature and a totally awesome way to form icicles and ice dams. Ice dams form when snow piles up on the roof. The upper portion of the roof is over the freezing point and the lower portion is below it. The snow melts near the peak, then refreezes at the edge. Ta-da! Ice dam.
The long rear roof is nearly twice the surface area of, say, a Cape. Twice as much area means twice as much snow accumulation and twice as much melt. Special attention needs to be paid to the insulation and airsealing to prevent ice dam conditions.
Venting – I’ve written a bit on the challenges of effectively venting houses here. Properly vented roof assemblies have several requirements: that there be a clear air flow path from the soffit to the peak, clearly defined air and thermal control layers, etc. Properly venting attics is hard enough. Properly venting a roof slope which may be 20 feet is that much harder.
Kneewalls – Original colonial saltboxes were post and beam framed. Modern saltboxes built with platform framing usually have knee wall supporting frames in the back. Kneewalls can be a pain to insulate and air seal, requiring a clear insulation strategy and attention to detail. Here’s my article on air sealing kneewalls in Cape Cods. Different style but the air sealing principals are the same.
Saltbox houses and the extended saltbox roof is an elegant reference to colonial times in modern construction. They have some of the problems of Capes and Colonials, the addressing of which can keep the house warm and efficient.