How To Lay A House Foundation

The most popular type of house foundation is a concrete slab. Follow these steps to lay your own concrete slab house foundation.

Preparing the Ground

After you have determined the desired thickness of your foundation, you need to get the ground ready to install it. Clear the ground and excavate a space that is twice the depth of what your foundation will be. Remove any large stones, branches or other such objects from the soil.

Next, level and compact the soil. This can be done with a rented compactor. Place a loose, even layer of sand or gravel over the area. This will prevent moisture from seeping up through the ground while you lay your concrete slab. Then lay some polyethylene as a waterproof  membrane over the layer of sand or gravel.

Building the Frame

Build a wood frame for the perimeter of the excavated site according to the specifications of your foundation. You will add screed rails (2x4 wooden boards) on the opposite and exterior sides of this perimeter.

Lay a straightedge (a 2x4 or other long and flat material) across the expanse of your frame, ultimately resting on the screed rails. Use metal stakes to support the screed rails. Place them so that the bottom of the straightedge sits at the level where the top of your slab will be.

Pouring the Concrete

Now you are now ready to start working with the concrete. After mixing the concrete, begin pouring it into your foundation frame. As the concrete fills the frame, the straightedge will slide across the screed rails, leveling the wet concrete. Once all the excess concrete has been removed and your concrete house foundation is leveled, remove the screed rails and straightedge.

Finishing Up

Use hand trowels or power trowels to remove flaws in the smooth texture of the concrete. This must be done while the concrete is still wet and malleable. Once you have completed this step, leave the foundation to dry and cure. Different types of concrete require different amounts of time to cure.