Techniques to Rebar on Blocked Fences

Variations

• The size, length, type and spacing of steel reinforcing bars in a concrete block wall vary with the wall. Most concrete block wall fences can be reinforced with 1/2 or 5/8-inch ribbed rebar, which are steel rods with slight protrusions along the length to provide better adhesion. Very tall walls may require 3/4-inch rebar.

Set in Footings

• Most wall fence rebar is set vertically into the footings before concrete is poured. Blocks are laid by placing the holes in the blocks over the rebar. This technique is used with both mortared blocks, with cement joints securing the blocks, or dry-stacked, with blocks set in place without mortar and secured with a surface bonding cement.

J-Style

• Short walls can use J-style anchor bolt rebar. This style has a hook bent on the bottom of each piece and a screw top so it can be used not only for reinforcing but to fasten a wall plate on top of the blocks. The J end is set in the bottom layer of block, extending up to the top of the planned wall height. The bent end holds it in place in concrete grout.

Horizontal Rebar

• Walls that need lateral reinforcement, along the length of the wall, have rebar installed horizontally, usually 3/8-inch to fit within 1/2-inch mortar joints. This rebar is laid atop a layer of block; some blocks have top grooves to accommodate this reinforcing.

Spacing

• Most fence walls over 4 feet high require rebar at every end or corner and about every 4 feet in between. Any openings, like gates, require rebar on each side of the opening. All rebar holes should be filled with concrete grout, tamped firmly into place around the bar with a long board.