Last fall, while documenting the attic of an 18th century house in Delaware, I got really excited when I spotted some carpenter’s marks carved on a set of 18th century rafters. It had been awhile since I had seen any. After discussing their purpose with my colleagues, I got to wondering just how common-knowledge these “marriage marks” are for other old house lovers. So I figured, why not write about them, since I think they are cool?
Simply put, “carpenters marks” are two matched symbols at the joints of timber frame buildings, used during the construction process for a building. Many people don’t realize that timber frame houses (and barns) were usually pre-cut and pre-fitted before they were actually erected. Since framing members were often hewn and fitted off-site, they could get mixed-up during transportation to the building site. This could even be the case when the timber was carved and stored on-site.
So builders would scribe carpenter marks into the individual framing pieces (posts, beams, rafters, braces, joists, or whatever) when a timber frame was being prepared on the ground, so it could be properly reassembled when the house or barn was raised. Framers did this because each joint was slightly unique, “custom-made” so to speak, since they had to carve each one individually. So — like snowflakes — no two joints were exactly alike, and if they mixed up, say, the wrong post with a wrong corner brace, the joints might not fit together properly. To understand how a timber-framed or “post and beam” building fits together, check out the illustration below, which reveals a skeleton of a timber frame house.
There were various methods to connect all of the pieces together, but this was usually accomplished through a “mortise-and-tenon” joint, which was generally “pinned together” with a peg (technically known as a “trenail” or “trunnel,” which is short for tree nail).
You can often spot carpenter’s marks — also called marriage marks (because you “marry” two pieces together), scribe marks, assembly marks, framers marks, craftsman marks, and lots of other things — in the attics of houses or all over the place in barns. Carpenter’s marks were almost always Roman numerals, since the straight lines of Is, Vs, and Xs were far easier to carve than the curves of Arabic 2s, 3s, 5s, 6s, 8s, and 9s. That said, there is a ton of variation of carpenter marks based on time period, location, building type, and the individual preferences of the wood worker.
One interesting thing I recently learned was that the Roman numeral system was altered for “4”s. Rather than a IV or IX, carpenters usually carved IIII (see above) or VIIII. I first noticed this when a classmate of mine, Karli Wurzelbacher (a doctoral student at University of Delaware’s art history program), pointed out an example of this in the attic of the famous Hancock House, an 18th century Quaker house in Salem, New Jersey (see below). When I researched it, I learned the reason for this was to avoid confusion with VI and IV (which doesn’t quite makes sense) or XI and IX (makes a lot more sense) when reassembling a frame on site. Pretty cool. [A reader has since pointed out that clocks from the same period also display the Roman 4 as IIII, which is an interesting point!]
Carpenters marks were etched into the wood using a chisel, scribe, or knife, or even a scratched in with a saw. The marks were most common before 1830 or so, though I’ve seen them on many later buildings. I’m not a carpenter and my understanding of building methods is limited, but the basic reason for their disappearance was that timber framers transitioned from “scribe rule” construction to “square rules” — meaning marriage marks for individual joints were unnecessary since joints were now cut in a more standardized, universal way (previously, each and every joint had to be carved to fit its matching piece individually, one-by-one). Also, writing in pencils and other writing devices were increasingly used in lieu of carving numbers. With houses especially, during the mid-1800s there was a shift from post-and-beam construction to building with smaller 2x4s and nails. So obviously, there was no longer a need for complicated joinery when you could simply nail two boards together.
A few more examples: A barn in Hockessin, Delaware:
An 18th century Cape Cod in Mansfield, CT:
A barn at Penn Farm in New Castle, Delaware:
Carpenters marks should not be confused with “tally marks,” which would be carved into flat boards to keep track of lumber (see below), or “layout marks,” used to mark where joints should be or pegs should be drilled, or “level” marks, which were used to make sure a building was level and square. Also similar are “ritual marks,” also called hex marks, anti-evil marks, etc., which were carved into the timbers of old buildings to ward off evil or protect against bad luck. Also, I saw some antique chairs at the historic house museum “Stenton” (in Philadelphia) that were carved with Roman numerals, as well (see below, below), presumably to number a set of matching chairs. Maybe I’ll write a separate posting soon about these other interesting marks!
Talley mark in a granary building at Poplar Hall in Delaware:
Antique chair at Stenton: