Putlog hole

Putlog holes or putlock holes are small holes in the walls of structures to receive the ends of poles (small round logs) or beams, called putlogs or putlocks, to form scaffolding. Putlog holes may extend through a wall to provide staging on both sides of the wall.

A historically common type of scaffolding, putlog holes date from the ancient Roman buildings. The term putlock or the newer term putlog date from the 17th century. and is still used today. Putlogs may be supported on the outer ends by vertical poles (standards), cantilever by one end being firmly embedded in the wall, or cantilever by penetrating the wall providing scaffolds on both sides. Putlogs may be sawn off flush with the wall if they cannot be removed but exterior putlog holes are typically filled in as the scaffold is removed to prevent water from entering the walls. Interior putlog holes may be left open, particularly if not in a finished space.

The inconsequential size and the spacing of the holes meant that they did not affect the solidity of the walls, and in well-preserved castles, like Beaumaris, the ancient putlog holes can be seen to this day.

Gallery
 File:Aigues-Mortes.jpg|Putlog holes for hoardings can be seen running along the top of the wall at Aigues-Mortes, France. Image:Echafaud.donjon.Coucy.2.png|Cantilevered putlogs support the access ramp scaffold in this castle construction. File:HEBI-Richtfest-5.jpg|Most of the putlogs are still in place in this scaffolding, the putlog holes are easy to see. File:Mendel II 054 r.jpg|A German plasterer at work with putlogs going into the half-timbered (fachwerk) walls. 