The foundation of your home should do more than just keep your house above ground. A proper, solid foundation will also keep moisture out, provide insulation against cold weather, and resist the earth’s movement around it. There are many different ways a foundation can be built, however, that does not mean that they are built to last and we want a foundation that will last forever! From pilings and piers to spread footings and more, foundations can be built in many ways. The most common in North America is the simple foundation wall made of poured concrete or concrete block, and a poured concrete footing system.

When building the foundation, you must take into consideration the conditions of the soil, quality of backfill, and water tables. Foundations must fit like a well-tailored suit where every minor detail is perfect. The base must be compacted correctly, the concrete free of voids, and the formwork set up properly. Fail to do even one of these things and the foundation itself is sure to fail. Here are some common reasons foundations fail:

1. Non-Porous Backfill

Clay or organic matter will hold water as if it’s a sponge. This will increase the risk of cracks in the foundation when the soil freezes and expands.

2. A Rushed Cure

The concrete must be slowly cured to reach its proper strength (preferably 3,000 psi). Wrap it in plastic, misting with water, and keep it damp for at least three days.

3. Insufficient Compacting

Pouring the slab over crushed stone that has not been tamped firmly will cause the foundation to settle and crack.

4. Improper Pouring Time

If you pour part of the concrete in one day and then come back the next day to finish, you will create a “cold joint” between the fresh concrete and the concrete poured the day before. This will cause the concrete to crack and leak. Always pour all the concrete in one day.

Foundation Design

Always consult a local builder or architect to review any foundation plans and how local building codes may impact the construction and design. There are three structural parts to a concrete foundation: a continuous concrete footing, a poured concrete foundation wall, and a concrete floor slab. These three elements combined serve as the foundation system’s structural components, which transfer the weight of the house (the gravity load) down into the ground. Reinforced bars of still (rebar) are placed into the concrete to help resist any twisting or bending caused by movement of the ground.

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