Framing projects that involve second stories and floors above basements frequently require the attachment of joists to the centre of a block wall. The most common way to connect floor joists to an existing breeze block wall is to attach a wooden ledge, called a "ledger," to the wall, then attach joist hangers to the ledger. With a hammer drill and concrete anchors, the average do-it-yourselfer can secure a ledger to a breeze block wall and start hanging joists.
Set up a ladder at each end of the wall. Mark the planned height for the ledger's upper edge at each end of the wall, using a tape measure and pencil. Attach a line level to a chalk snap-line, and stretch the line's string between the marks you made for the ledger's upper edge. Use the line level to level the string. Remove the line level from the string, and snap the string against the wall to lay out the location of the ledger's upper edge.
Use a framing square and pencil to mark the locations for concrete anchors on the wall: two anchors at each end, plus staggered anchors through the ledger's centre, with all anchors placed away from the ledger's edges.
Attach a masonry drill bit to a combination hammer drill. Drill a hole at each concrete anchor mark. Remove the nut and washer from each concrete expansion anchor. Insert a concrete expansion anchor into a drilled hole and pound the anchor with a hammer. Install an anchor into each drilled hole.
Cut the ledger framing lumber to length with a circular saw. Mark the locations of the concrete anchors on the surface of the ledger. Attach a wood-boring drill bit to the combination hammer drill, set the drill to the "drill" or "driver" setting, and bore a hole through the ledger at each mark.
Slip the ledger over the concrete anchors, slide a washer onto each anchor, and thread a nut onto each anchor. Fully tighten the anchor nuts with an adjustable wrench.
Lay out the positions of the joist hangers on the upper edge of the ledger. Space the joist hangers according to your engineered design or blueprints. Fasten joist hangers to the ledger using a framing hammer and joist hanger nails. Attach a ledger and hangers to the opposite breeze block wall, if necessary.
Lift a joist into a joist hanger. Fasten the joist to the hanger with a framing hammer and joist hanger nails. Lift and fasten the remaining joists.
Hire a helper to assist with lifting long, heavy joists.