Laying masonry overhand means the mason stands on the inside of the wall and reaches over the top to lay and strike the joints on the exterior face. This technique is often used when exterior scaffolding is impractical or too expensive to erect, though it makes it harder to keep the outside face perfectly plumb and clean.
Heard on the job
We can't get a scaffold in that narrow alley, so we'll have to lay the whole east wall overhand.
Insider tip
Striking joints overhand requires a good feel for the tool, as the mason often has to work blind or at an awkward downward angle.