Building and Framing Perfectly Square Walls

When laying out wall plates and snapping chalk lines for the location of walls; it is critical to have the walls square with one another.  If you skip this step you may end up with out of square kitchens, bedrooms or even a basment wall. 

Problems you will encounter with out of square walls:

• Flooring with a pattern or tile that does not fit or look properly
• Out of square drywall
• Mis-aligned walls
• Trim that does not fit properly
• Cabinets that won't fit together properly

The best method is to check all lines and walls for square prior to building and installing them. It will save you a lot of headache down the road. Just think of your walls as a right triangle. Right triangles are on a 90 degree angle. This is the perfect angle for walls.

This is called the Pythagorean Theory. You will be finding the hypotenuse of a square.  Look at the right triangle above.  It has an A, B and C side. The formula to find C - which would be the diagonal measurement you will need to check your wall for square- is A²  + B²  = C². 

On our triangle above: if A is 3 and B is 4 than C would be 5.  The formula is (3x3)=9 + (4x4)=16  which = 25 and the square root of 25 = 5. Therefore our diagonal measurement needs to equal 5 or the triangle or your wall is not square.

This can be a very time consuming way to verify all your walls are square; so here are a few tips:

1. Build and square all the perimeter walls first. Once you know these are square it is just a matter of measuring off the outside walls to square interior walls.
2. If you have a small wall to build you can use the 3-4-5 Method above. The dimensions 6' and 8' equals 10' for the diagonal measurement for longer walls (6-8-10 Method).
3. There are construction calculators available that will compute these for you. The great thing here is they will even do fractions! A construction calculator will run between $40-$100.