House Leveling Techniques

Underpinning

• House leveling is commonly called “concrete underpinning” or just “underpinning.” There are many methods used. All of these methods require a form of drilling into the existing foundation and using some kind of material to support the structure where it is sagging or sinking into the soil or sand. All methods of underpinning or leveling require excavation of the foundation and, in most cases, drilling into the concrete and inserting something that will give extra support and “lift” the structure. None of these techniques are guaranteed to work; many of them force even further sinkage if done improperly, or if the soil is too unstable to withstand the structure.

Conventional

• The oldest and most common method of leveling is to dig several pits near and under the foundation where it is sagging or sinking. A pit or trench is dug where the foundation is sinking, and, underneath the lowest point of the sinking foundation, concrete is poured. This extra support will, over time, force the other, non-supported sides of the house to sink in compensation, leveling the house. In some cases, this will just prevent any further sinking.

Nails and Brackets

• Piles and nails are similar to each other. The “nail” technique is slightly smaller, and which one is used depends on the structure. For a house, the nail or concrete technique will likely be used. The “bracket” technique inserts a group of piles or nails at regular intervals in the sinking side of the home. These piles are then connected with one another with a steel bracket that adds lateral support, taking some of the weight off the piles or nails. The bracket will be used usually in heavier structures like hospitals, schools or public buildings. Most residential homes use micropiles or concrete pits.

Micropiles

• Drilling into the middle of the concrete foundation on the side that is sinking, small but very sturdy piles are fixed in place. This serves to “lift” the house, expanding the foundation on the side that is sinking. Current piles are rated up to and exceeding 200 tons.

Resin

• A new method developed in New Zealand uses tiny holes drilled into the middle of the concrete foundation where resin is injected. This resin then expands, as it is designed to do, thus lifting the house. This resin, expanding into a powerful and hard foam, fills any cracks or holes in the foundation.