In the construction of

masonry Masonry is the craft of building a structure with brick, stone, or similar material, including mortar plastering which are often laid in, bound, and pasted together by mortar (masonry), mortar. The term ''masonry'' can also refer to the buildin ...

buildings, a fire cutBrannigan, Francis L., and Glenn P. Corbett. ''Brannigan's building construction for the fire service''. 4th ed. Sudbury, MA: National Fire Protection Association :, 2007. Print. or fireman's cut is a diagonal chamfer of the end of a joist or beam where it enters a masonry wall. If the joist burns through somewhere along its length, damage to the wall is prevented as the fire cut allows the joist to fail and still leave the masonry wall standing. Without firecut joists, if the burnt joists fail and rotate the unchamferred ends of the joists as they deflect downwards, this would damage the masonry wall at the connection point and possibly pull the wall inwards.

References

Masonry Carpentry {{carpentry-stub