Securing Wood Furring Strips to Concrete Block

Coat the block walls with a coat of masonry waterproofing agent. The paint will act as a vapor barrier to hold back water and moisture that can seep through concrete block and damage furring strips, insulation and finished walls.

Decide whether to run the furring strips horizontally or vertically across the walls. The installation process is the same either way, but one or the other may be preferred depending on the reasons for adding furring strips. Mark the wall with penciled lines to show where the strips will be located. Space the lines 16 inches apart on center. Use a carpenter’s level to make sure the lines are plumb, if running the strips vertically, or level if running them horizontally.

Stretch a chalk line across each of the pencil lines and snap a mark to make the lines more visible.

Cut the furring strips to the sizes needed for your application. Use a circular saw, table saw or miter saw to make the cuts.

Run the carpenter’s level across the wall to note where the walls have high or low spots and mark those locations with a pencil. Since they are thin and narrow, furring strips will follow the wall’s contours. You will need to know where wall irregularities exist so you can adjust for them later.

Lay down a bead of construction adhesive onto the back of a furring strip to strengthen adhesion to the wall. The adhesive will also help hold the strip in place while you drill. Apply the strip to one of the chalk lines you snapped earlier and check it for level or plumb.

Attach a pilot bit to your hammer drill that matches the shaft diameter of your concrete screws. Drill a pilot hole through the furring strip and into the block. Insert a concrete screw, and use the combination driver to screw it in place. If you are crossing one of the low spots you marked on the wall, add a shim between the strip and the wall to level or plumb it before driving the screw in all the way. Recheck for plumb or level.

Adjust the furring strip at high spots you previously marked by shaving off some of the strip with a block plane, and check the work with a level.

Repeat until all the furring strips are secured in place.