How To Pour Concrete on an Existing Concrete Slab
- 1). Measure the existing slab. Then measure, mark and cut two-by-fours with a circular saw to make forms that will go along the top edges of the existing concrete slab.
- 2). Drill pilot holes into the side edges of the existing concrete slab using a masonry bit. These holes will be used to affix the forms along the top border of the concrete slab.
- 3). Fasten 1-inch by 3-inch stakes to the two-by-four forms with a screw gun and stainless steel screws. Then fasten the stakes to the side edges into the pilot holes using a screw gun and cement screws.
- 4). Combine one part Portland cement with three parts sand in a wheelbarrow, moisten with a hose and mix together with garden hoe. Add gravel, if desired, to strengthen the concrete.
- 5). Pour concrete bonding agent onto the existing concrete slab while the new mixed mud is still wet. Immediately spread the newly mixed mud over the bonding agent.
- 6). Smooth the surface of the wet mud with a trowel and allow to cure for a period of 24 hours. After 24 hours has passed, remove the screw securing the forms with a screw gun, then tap the forms off the existing slab with a hammer.
Source...