How to build a foundation for a house

Updated March 23, 2017

There are several different types of foundations for a home. Which type of foundation is favoured in your area depends on many factors, such as the type of soil present and how cold your winters get. The easiest type of house foundation to build is the slab foundation. This type of foundation is favoured in warmer climates, so check your local planning requirements to see if a slab foundation is right for your home.

Level the area where you intend to pour your foundation. It is not necessary for the pad of a slab foundation to be perfectly level, but your pad area should be fairly level. Making your pad level right from the start will save you time and headaches later.

Dig a trench all the way around the perimeter of your foundation. This trench will be an important part of your foundation. It should be a minimum of 15 cm (6 inches) wide and 60 cm (24 inches) deep. If the ground in your area typically freezes in the winter, your foundation trench needs to be deeper than the permafrost line. If you are building a house that is two or more stories tall, then your foundation trench will need to be wider than 15 cm (6 inches); check building regulations for the exact width required for your geographic area and soil conditions.

Build a frame all the way around your trench using your 1.3 cm x 20 cm x 3 m (1/2 inch x 8 inch x 10 foot) framing boards. Hold the boards in place with wooden stakes. Your foundation frame will be built on both sides of your trench, in effect raising your trench 20 cm (8 inches) above the level of the ground. Using long boards and a good level, make certain that your foundation frame is perfectly level. This may require that you lower or raise sections of the frame. Start at one corner of your foundation frame and work out from there. It is vital that your entire frame be level.

Place bricks in the bottom of your trench, spaced in such a way that you can lay two rows of rebar in your trench with the rebar supported by the bricks. Fill your trench with concrete all the way to the top. Smooth the top with a trowel if necessary.

Remove your foundation framing boards. Fill the inside area of your pad with gravel 10 cm (4 inches) deep. Place your 4 mm (5/32 inch) plastic sheets on top of the gravel to act as a moisture barrier. Use bricks or mesh supports to form a base on which you can lay your wire mesh. Fill the entire inside of your pad area with concrete. Your cement should be approximately 10 cm (4 inches) thick and match the height of your trench foundation perfectly. Smooth with a trowel if necessary. Allow to harden.


Make sure all electrical lines and sewer and water pipes are in place before pouring your pad, as they will be permanently encased in your foundation.

Things You'll Need

  • Concrete
  • Gravel
  • Rebar
  • Several dozen bricks or half bricks
  • Wire mesh
  • 4 mm (5/32 inch) plastic sheets
  • Digging tools
  • Bubble level
  • Trowel
  • 1.3 cm x 20 cm x 3 m (1/2 inch x 8 inch x 10 foot) framing boards
  • Several wooden stakes
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About the Author

Larry Parr has been a full-time professional freelance writer for more than 30 years. For 25 years he wrote cartoons for television, everything from "Smurfs" to "Spider-Man." Today Parr train dogs and write articles on a variety of topics for websites worldwide.