The Hammerbeam roof, the work of Hugh Herland, has been said to be quite without rival in any part of the world. Certainly this is the largest medieval timber roof north of the Alps, and the Hall is one of the largest ancient buildings in Europe which is undivided by columns. The Hammerbeam from which it is named is the horizontal beam which projects from the top of the wall, supporting the struts and arched braces which hold up the roof proper. Here the ends of the hammerbeams are decorated with the figures of angels, which were carved by Robert Grassington.

The Timbers of the roof came from Hampshire, Surrey and Hertfordshire; having been prepared at Farnham, the timbers were floated down the river from Chertsey to Westminster.