Cape Cod Style Houses

by Erik North on November 16, 2011

Cape Cod Style House


OK, I’m re-using the photos from last week’s post. Heck, it’s my house. Why not.

I wrote last week about the difficulties with heating Capes. Cape Cod style houses are enormously popular throughout the country and particularly in their region of origin, New England. The style has been around for centuries but leapt into popularity after World War II. Young Baby Boomers looking for inexpensive starter homes found Capes to be ideal. Cape Cods are common subjects for audits, with some notorious (but relatively easy to fix) Achilles’ heels.

Cape Cod Style Houses – The Boring Wiki Style Definition

Cape Cods are a very popular housing style dating back to the 17th century. They are characterized by steep pitched roofs, half-height knee walls and full gable end walls. Older construction often locate the chimney centrally while newer variants move it to one of the gable ends.

Like I alluded to earlier, Capes have grown enormously in popularity because of their compact, affordable design. One irony (and we’ll get to this!) is that the difficulty of air sealing the second floor knee walls make the design challenging one when ocean breezes on the actual Cape Cod whip through the building.

Cape Cod Style Houses – Advantages

The advantages of the Cape Cod come from its compact design. There’s a Latin phrase “multim in parvo” used to describe pugs. It means “A lot in a little” which is an apt description for Cape Cods. There’s a lot of living packed into a small footprint. The layout can accommodate up to four bedrooms and with a dormer can easily accommodate bathrooms on both floors.

Their footprint makes Capes appealing for infill construction (small lots split off other lots in the city). For the budget conscious first time home buyer, Cape Cods are a great choice.

Cape Cod Style Houses – Disadvantages with Insulation

Capes have some real challenges keeping warm (check out this article for a summary). The vast bulk of Cape Cod style houses in the US were built between 1925 – 1960 (from the Great Depression through the Baby Boom). What else happened during that time? Not insulation that for sure. Many Capes predate the modern conception of insulation.

Cape Cods often have no insulation, very old versions of insulation (my Cape had “Kimsul”, an odd cellulose and kraft paper deal and one of the oldest commercially available insulations in the US) or a half-assed retrofit job. Start with the assumption that older Capes need their insulation improved and then start figuring out how.

Cape Cod Style Houses – Disadvantages with Air Leakage

Air sealing … oh, boy. The second floor knee walls in Cape Cods leak air like crazy. The knee walls are framed on top of the floor joists, connected to the roof rafters. Here’s a diagram of an attic knee wall in a Cape Cod style house:


Warm air flows from under the knee wall, roof deck and out the attic’s vents. Often the knee walls have built in bookshelves, closets and drawers which leak air like crazy.

When retrofitting a Cape’s attic, a great deal of attention should be paid to air sealing. If the soffits are vented, the air flow needs a clean, uninterrupted path from the soffit to the peak. If the soffts are unvented, consider insulating with an unvented design (with all that entails).

A Cape Conclusion

Cape Cods are a justifiably popular housing choice. They’re a great affordable pick for a first time buyer or small family. However the insulation and air sealing often needs detailed work.

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