DOMESTIC BUILDINGS RESEARCH GROUP (SURREY)



Carpenters' Marks - page 1

First thoughts on Carpenters' Marks

(first published in DBRG News October 2004)

Many of you will have taken “rubbings” of carpenters' marks when recording a building, but just what exactly were these and where are they found? Richard Harris sets out the reason for and nature of marks in “Discovering Timber-Framed Buildings” (Shire) but they get hardly get a mention in most learned works. This article is a first thought on carpenters' marks in Surrey, and is meant to stimulate discussion and observation by members so that directions for further study can be identified which will lead to a future more rigorous publication. Your thoughts would be welcome.

Making sense of the frame.

Before turning to the various numbering systems we must remind ourselves how a building was set out. The frames of a timber-framed building, or the roof and floors of a medieval building, were prefabricated by the carpenter on the ground to ensure each piece would fit with the others. These 'frames' are always flat, that is two dimensional, and the building is made up of a series of such frames.

fig1

The first one to consider is not normally considered a frame. This is the grid of ground cills on which all of the other timbers will sit. In a standard rural house the frame is set out like a ladder with the cills of the long walls being continuous¹ and the intermediate timbers that will form the base of any cross walls being mortised between them like the rungs of a ladder. Ground cills² have seldom survived but I have known them to be numbered in the same way as the walls which I will describe shortly.

The main timbers of the front wall were also put together like a ladder laid on its edge. The bottom member is the ground cill already mentioned and the top is formed by the wall plate which will be under the eaves when the house is erected. Between these are what will become the principal posts defining however many bays there are to be in the building. The smaller timbers within each bay are generally also framed like a series of finer ladders. This construction technique is simple to assemble and makes for inherently rigid frames although braces were also included.

The end and intermediate walls were made up the same way. In these instances the principal posts and the ground cill do not actually engage with one another as both are tenoned into the long-wall cills. The same situation occurred with the tie beam and principal posts once jowls stopped being used so the carpenter must have had some trick to prevent the timbers moving when framed up.

The tie beams of the cross frames of all but the earliest buildings support a truss consisting of two principal rafters and a variety of intermediate members. As we will see these top triangles were normally considered as separate frames.

The common rafters of a crown post roof have collars that look like a series of capital 'A's. These are effectively a series of multiple frames forming a set. By the time roofs had butt purlin, butt rafter roofs the whole of the roof plane was considered as a frame.


¹ Obviously long cills would have to made of several timbers scarfed together.
² If you find the principal posts extend below an 'interrupted ground cill' then you should look for evidence that the what you are looking at is an alteration. The only common exception is found in barns where the principal posts flanking the wain doors sometimes extend below the ground cill.



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©DBRG 12th June 2006