How to Replace Sidewalk Ramps With Nubs

Measure the location of your sidewalk nub over a paved road or driveway adjacent to the ramp with a tape measure. Screw 4-inch masonry screws into the surface using an electric screwdriver or drill with a screwdriver bit to mark the general footprint of the nub. Measure the height of the sidewalk curb and multiply it by the area of the nub to determine the volume of concrete you need.

Measure 2-by-6 lumber to create the form, or mold, that you'll pour concrete into to form the nub. Mark the lumber and then cut it to length with a hand saw so that it will stand on its 2-inch end and provide a wall around the shape of the nub.

Splice pieces of lumber together where they will abut one another by cutting corresponding notches in each piece of wood with the hand saw. Screw the notched pieces of lumber together with 1-inch wood screws to form a tight seal.

Secure the lumber form by driving additional 4-inch masonry screws into the paved surface directly next to the lumber. Screw 4-inch masonry screws through the wood at the ends of the form at an angle, driving them into the existing sidewalk curb around the ramp.

Pour crushed stone into your form to create a smooth 2-inch layer that will serve as a base for the concrete. Ensure that the crushed stone also fills in the lowest 2 inches at the base of the ramp.

Lay sheets of metal mesh on top of the crushed stone layer throughout the nub form.

Transport concrete from a mixer to your sidewalk nub using a wheelbarrow. Pour the concrete directly on top of the metal mesh and crushed stone, emptying the wheelbarrow with a shovel.

Spread and smooth the wet concrete with a concrete rake, filling in all parts of your nub form, including the ramp.

Bring additional wheelbarrow loads of concrete until the nub form is filled and the level of the nub is even with the level of the old sidewalk.

Smooth the entire surface of the nub with a concrete float, making wide strokes over the surface of the wet concrete. Give special care to the ramp, where the new concrete must rise to the level of the surrounding sidewalk to form a smooth transition.

Wait for the concrete to dry, based on the supplier's recommendation, before unscrewing the masonry screws holding the lumber form in place. Remove the lumber. Patch screw holes in the driveway or road using a tube of asphalt crack filler to prevent water damage.