Old houses: plank construction
In many regions of the United States there are homes built entirely of planks, without any structural framing behind the boards. You might be thinking: "how is it possible for any wood building to survive without the well established and proven method of a wood-frame skeleton to support loads and resist other forces?"
Just like my favorite seafood crawling at the bottom of the ocean, it has a strong exoskeleton.
Types of Plank Construction
There are two methods of plank construction--horizontal and vertical. The first, built of thick horizontal boards is strictly known as a "plank house." These are mostly from a very early period and are found in some areas along the East Coast. The thick planks, usually hand-hewn and sometimes rough-sawn are usually joined at the corners with joints typical of hewn log homes. Many are often mistaken for log homes as the planks are usually four inches or more in thickness.
The second, more common style of plank construction is built with vertical planks. The earliest examples are mostly found in the Northeast. These are also built with thick, hand-hewn planks but are attached to a wood timber frame. These are also referred to as "plank houses," but the structure is still relying on a frame and only wall studs are omitted.
The most common type are those that the walls are truly built entirely of the boards that most picture when discussing planks. These planks are typically 1-1/4 to 2 inches thick and extend from the foundation to the roof. This type of house, most commonly built between 1870s to 1910s, was known as a plank house, box house or battened box house. Box house is a good descriptive term as the method of construction reminds me of old wooden shipping crates.
Regional Variations of Plank Construction
There are regional variations, but the basic wall structure consists of random width vertical planks nailed to a sill or horizontal board at the base of the wall and then nailed to another horizontal plank at the top of the wall. There's no joinery or other reinforcement used where the walls meet at the corners. The seams between each board were usually covered with narrow wood strips, called battens.
I've heard many folks discovering newspaper or cloth used to cover the inside of the planks. If there is a second floor, the joists are usually supported at the ends by another horizontal board nailed across the vertical planks. Sometimes the joists are mortised into the wall planks. The roof rafters usually are simply supported by the horizontal boards at the top of the walls.
Photo credit: Jim Katan, Portland OR
Plank Construction: Box Houses
Although it's not a common or a well-documented type of structure, it was much more widespread than the aforementioned plank types. The low cost, combined with the little skill needed for their construction, made it a popular house type in communities where quick and/or inexpensive housing was in demand. Groups of these box houses are typically found in communities that were originally company-built mining towns, lumber camps, tenant or workers cottages on farms, and summer resort communities that were popular around the turn of the last century. Many probably aren't recognized as a box house as they are later covered with newer siding materials. Since it's not possible to run concealed electrical wiring and plumbing pipes, walls with studding have often been added throughout the interior.
In books and manuals on house construction of the period, I've found very few references to this type of building. There are very few description of methods or techniques of this "standing boards nailed together" type of construction. It also seems to have been viewed with condescension by those writing during the time of their prevalence.
I'd bet they'd be surprised at how well many have survived and how some have been transformed into fine homes.
William Kibbel III is a home inspector and restoration consultant specializing in historic residential and commercial buildings. He is vice president of Tri-County Inspection Company serving Southeastern Pennsylvania and Central New Jersey.