Did medieval carpenters always work in green wood?

Another popular misconception is that medieval carpenters always worked with freshly cut, or green, wood. When a tree is freshly cut, the wood contains a great deal of water. As this water dries, the wood will tend to shrink and harden. Such changes can result in warps, twists, and splits in the wood, as parts dry at different rates. Today, most lumber sold has been "seasoned," either through natural drying or controlled heating in a kiln.

There's no doubt that fresh timber was frequently used. Green wood has several advantages for the woodworker: it works easily and tends to dull tools less than seasoned wood. Fresh timber also splits easily, important when riving boards from larger timbers. Using fresh timber also doesn't require the craftsman to incur the cost of keeping an inventory of lumber on hand.

But despite these advantages, a little research shows that the virtues of seasoning lumber were also well known in the Middle Ages. Our friend Leon Battista Alberti again instructs us:

"We have seen our own carpenters immersing timber in water and leaving it covered in mud for a period of thirty days, especially if it is to be used for turning; they say that it will accelerate the curing process and make the wood easier to manage, whatever the intended use."¹

He also noted:

"... timber will be more reliable if the tree is not felled immediately, but the trunk is ringed and allowed to stand and dry out; and that the fir, a tree with little other defense against contagion from moisture, will, if stripped of its bark while the moon is waning, never rot in water."²

In building contracts from the 14th and 15th centuries, there are several specific mentions that building timber was to be seasoned. In 1355/6, a letter addressed to the Archbishop of York pled for additional materials:

"...unless new timber is cut during the winter season, so that it may dry off (exsiccari) during the summer, the carpenters and our other workmen employed on the building of the said work will, for lack of timber, stand absolutely idle throughout the next winter season."³

In some forms of joinery, the changes in size and shape that come about through drying can be used to advantage. For example, if a dry, round tenon is placed in a relatively green mortise (hole), the mortise will shrink about the tenon and lock it in place.

Notes

(1) Alberti, Leon Battista. On the Art of Building in Ten Books. (Rykwert, Joseph; Leach, Neil; and Tavernor, Robert translators) The MIT Press, Cambridge, 1996. p. 41

(2) Ibid., pg. 40.

(3) Salzman, L.F. Building in England Down to 1540. Oxford University Press, Oxford, 1952 (Special edition for Sandpiper Books Ltd., 1997), p. 239.

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Copyright 2006, Tom Rettie. Content may not be republished in any form without permission of the author.