Key Into Existing Brickwork by Drilling — Not Chiseling — the Pocket

The Problem

Keying in — cutting pockets into an existing wall so new brickwork tooths into it — is one of the most hated jobs in the trade for a reason: attacking the pocket with a hammer and chisel sends shock through the wall, and the cracks it opens in the surrounding joints cost more than the tie-in was worth.

The Technique

1. Mark the brick to come out, and drill it with a series of holes — a 6mm masonry bit, four holes across the brick. Drilling removes material without the impact that cracks neighboring joints, and the perforated brick comes out with a light touch instead of heavy blows.
2. For the mortar left on the sides and bottom of the pocket, make the raking tool: take one of the masonry screws you're using on the job, cut its head off, and chuck the shank in the drill. The screw's hardened thread chews the old mortar out of the pocket cleanly.
3. Rake the sides and bottom, give the remains a light tap, and clean out the pocket. It's ready to receive the new brick.