Do it yourself!

Tuesday, July 21, 2009

How To Square A Building Foundation

When a building is being erected it is critical that the foundation is very square. A good method to use on small buildings, 8’ x 8’ or smaller is to use the framing square and string. For larger buildings it is better to use the 3,4,5 method.

Tools Needed

Steps To Take

  1. You start out by running a strait line on one side of what will be the base.
  2. Then you pick a point on that strait line to be your first corner point.     Since you now have the strait line stabilized you can mark the string line itself with a marker.
  3. At the other end of the strait line you must pick a point that will correspond with the size of the base are foundation you are building.     Mark this point on the string also.
  4. Then you go back to the first point that you marked on the string and lay a square on that point. Have the other end of the square facing in the same direction of the base. Since a square is set on ninety degrees this will be the first square corner of your base.
  5. .You now run another string in line with the other end of the square giving you a right angle or ninety degrees. You then pull another string on this right angle.This will give you the second side of the base or foundation. You now have a true right angle to work with.
  6. You then measure from either of the existing lines to the size of base or foundation you want, installing lines to these points. You now have a square base or foundation.

    Another way to check your work is to pull a tape from corner to corner of your string lines. If you are square the measurement will be the same both ways.
    If your base or foundation is larger than the above you will need to perform the following. It is called the three four five method. This is achieved by establishing a strait line like before. Starting at the first point on the line and measuring down the line three feet and put a mark on it. Now on the other line going at a right angle, start at the first mark and mark four feet down the other line. You now have three marks on the lines. Measure between the second and third line five feet making a triangle. If the measurements come out on the marks you have a right angle and your base or foundation is square.


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