Why bat closers matter- Learn the essentials
To make the a patterned bond fit within the constraints of a building assembly space, masons use brick closer or brick bats. Bat closers are very common, they are essentially bricks that have been cut in half. Quarter closers, on the other hand, are less common but similar. They are bricks that have just been cut down to approximately one quarter of the typical width.
The practice of using a single partial sized brick, per course, for fitting the entire course together within a constrained dimension is extremely common, it’s an everyday type practice in historic brick masonry. The image below shows a close up view of the area of infill. On the right hand side we have taken the same image but overlaid the area of the quarter closer with a pink color to highlight those areas where quarter closers were used.
Bat bricks have a variety of applications, but they are commonly used in running bonds, common bonds, and in Flemish bonds to make up a terminating course end at half or portion of the full brick width.
In a double wythe wall, half-bat brick cutting can usually be avoided by turning a brick to span between courses in a header position.