How to Prepare a Foundation

When beginning a construction project, it is important to take great care in properly setting up the foundation. The success of the project, whether it is a large house or small tool shed, relies heavily on the care and effort that has been put into the site preparation and layout. While the techniques described in this article can be employed to some extent on any scale project, they are tailored to the small to mid-scale home project. This is a basic guidance to a do-it-yourself builder.

Steps

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Place stakes at each end, oriented as desired. It is important that the stakes lie along the same edge, namely, corners 1 & 2 as shown in Figure 1, not corners 1 & 4. Bang in the stakes using hammer or equivalent tool.
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For a 90° triangle, a^2 + b^2 = c^2 when c is the hypotenuse. Figure 1 shows how this relates to laying out the foundation. Find the distance A using A=sqrt(w^2+l^2).^{[1]XResearch source}
Lay it out starting at one of the first two corners staked out, more or less along the diagonal line shown in the figure above.
From the original corner staked out that is not in contact with the string, measure out the length (or width) perpendicular to the side previously laid out. Hammer in the third stake at the point where the end of the string meets the measured out distance of this side. Note: The point of this step is to ensure that the foundation is square, so adjustment of the angle at which the string and/or side are laid out may be required.
Start at the original stake not already used to anchor the string.
Use the metal rake (and shovel if necessary) to roughly smooth out and level the entire area within the boundaries of the foundation. This step is just to ready the area to be leveled precisely, so don’t spend too much time trying to “eyeball” it.
Do this as shown in Figure 2, making sure that no gaps are visible between the ground and the bottom of the 2x4. Note: If the board is shorter than the edge being leveled, place one end of the board at a corner to leave a gap beyond only one end of the board. Do not attempt to center the board.
If the board is level and gap free, skip step 10.
Keep the base smooth under the length of the 2x4 so that no gaps form. Do this until the 2x4 is level. If the board is as long as the side being leveled, skip steps 11 & 12.
Cover the gap left along the edge being leveled. Leave at least 2-3 feet (60cm - 91 cm) of overlap between ground leveled in step 10 and the 2x4.
Bring the unleveled ground to the same elevation as the area already completed. If there is still a gap of unleveled ground, repeat steps 11 & 12.
Use the rake to level the ground in front of the board.
Bring it 1-3 feet (30.5 cm - 91 cm) as shown in Figure 3, and repeat steps 9-12. Do this all the way to the other side of the foundation. In the area between board placements, use the rake to smooth out the ground, and bring it to the elevation of the area leveled underneath the boards.
This means starting along either of the two edges that haven’t been leveled along their lengths. This should be easier than the first pass, as the foundation has already been leveled in one direction.
To do this, lay the 2x4 diagonally across the center of the foundation, with each end pointing at opposite corners (the same orientation as the string in the beginning of this process). By placing the level on top, you should be able to confirm that the whole section is level.

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Are there rules to follow or permits needed in the state of California?
Agustin Renoj
Home Improvement Specialist
Agustin Renoj is a Home Improvement Specialist with Renoj Handyman based in the San Francisco Bay Area. With over 18 years of construction experience, Agustin specializes in carpentry, painting, and exterior, interior, kitchen, and bathroom renovations. Renoj Handyman is a family-owned business that consists of craftsmen trained in all areas of construction.
Agustin Renoj
Home Improvement Specialist
Expert Answer
For a construction project in California, several steps must be followed. Firstly, sketches or drawings need to be obtained and submitted to the city for approval prior to commencing any work on the foundation. Once this initial approval is secured, the process of laying the foundation can begin.For a new addition to an existing structure, the foundation must be securely anchored to the original house. This involves digging a trench at the desired location and ensuring that the ground beneath is solid and stable. Rebars are then attached to both the original foundation and the new addition to provide structural support.During this process, attention must be paid to the placement of the rebars. They should be elevated approximately three inches above the ground to prevent contact with soil, thus avoiding corrosion and ensuring structural integrity.Once the foundation is in place, it is typically necessary to obtain a building permit and schedule inspections as required by California regulations. Inspections are crucial to verifying that the foundation has been constructed correctly and meets all safety standards.In summary, laying a foundation for a construction project in California involves obtaining approval from the city, excavating and preparing the site, anchoring the foundation to existing structures, and ensuring compliance with building codes through inspections.
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Tips

If backfill is available, you can choose to raise or lower elevation when leveling ground.^{[2]XResearch source}
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In step 4, it may be easier to tie the string off to the starting stake. If doing this, it is important to be sure that the string still reaches length A from the stake after being tied.
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Making the foundation “square” does not mean that the length and width are equal. It means that the angles are all 90°, and the shed being built will be a rectangle rather than a parallelogram.
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Things You'll Need

Metal rake
Measuring tape
Mallet, hammer or large rock
Shovel
String
4 wooden stakes (or any object that can be stabbed into the ground)
Straight 2X4 (60 cm x 1.2 meters) (preferably the length of the shorter foundation dimension)
Level
Spray paint-you can make outline your foundation for straighter edges and also mark spots in the foundation that are too high or too low