How to Level an Unlevel Front Porch Made of Concrete
- 1). Use a carpenter's level placed on the surface of the slab to determine which side or corner of the slab is lowest. This is the area that you'll want to apply pressure to in order to raise the slab.
- 2). Drill a minimum of four one and 1/2 inch in diameter holes using a drill equipped with a masonry bit through the slab into the soil beneath the section of the porch you wish to raise. Arrange the holes evenly spaced in a line over the area.
- 3). Connect a hose to a mudjacking pump. You can rent a pump at an equipment rental shop or at some home improvement stores. Run the hose to the slab and push it through the hole located in the highest area of the slab until it reaches the soil beneath. Take care not to push the hose into the soil itself as you may clog the end.
- 4). Mix the mudjacking filler material in a wheelbarrow using a mixing paddle attachment on the drill. Use a mixture containing two parts sand, one part Portland cement, one part flyash, and an expander additive to reduce shrinkage during the curing process. Add the amount of additive suggested by the additive manufacturer according to the amount of filler you're using. Add water to the mixture until you've created a filler of a consistency that's easily pumped. Fill the pump with the filler material using a spade.
- 5). Turn on the pump and pump the filler material beneath the porch slab using a pressure setting of 10 PSI. As you pump the material beneath the slab, the slab will begin to rise.
- 6). Switch the hose to the next lowest hole when the area beneath the current hose is nearly level, moving down the holes until you've reached the furthest one. Filling the void beneath this hole should bring your porch slab completely level. Watch the carpenter's level to note the point at which you've leveled the slab.
- 7). Turn off the pump and remove the hose from the last hole.
- 8). Mix a new batch of mortar consisting of three parts sand and one part Portland cement in a bucket. Mix in some of the concrete dust created when drilling the holes in the slab so that the mortar matches the slab color. Add water until the mix is about the consistency of peanut butter. Fill the mudjacking holes with the mortar and then level them at the surface of the slab with a trowel. Allow the filler material 3 weeks drying time.
