Taper burn marks are found on wood in medieval and later buildings and were once believed to be no more than the result of unguarded candles.
Detailed studies, however, have shown that these markings are commonly located in places where there is little or no chance of a lighted candle having been left. These include roof timbers, wall plates and timber hidden beneath the floor.
In addition, experiments have shown that a taper or candle has to be applied to the timber at a specific angle to create the distinctive tear-drop shaped mark and that in many cases the mark must have been made before the timber was put in place. Other experiments suggest that the considerable depth of some marks appears to be the result of repeated burning, scraping away and re-burning. The current thinking is that many, if not all, such marks were applied to the timbers during, or even before, construction and that they were created to guard the building against lightning, and more specifically, fire. It can, in some respects, be thought of as inoculating the building, the premise being that if timber is burnt once, it cannot be burned again.
The markings are also sometimes found in churches, most often on the inside of the main door. Examples in Devon include on rood screens, and on timber stairs.