How to Square a Building

Everything from carpeting a room to installing cabinets is more difficult -- and sometimes less effective -- if the space you're working in isn't square. Whether you want to renovate, re-tile, or build a deck, learning how to square your space will make the job easier and the outcome more professional.

What you need:

Measuring tape
Chalk

Here's what you do to define a square work area:

Decide how large an area you want to work on.
Place the measuring tape at the point where the two intersecting lines meet.
Pull the tape measure out the desired length. Mark the place on the floor with a chalk mark.
Once again, place the measuring tape at the point where the two intersecting lines meet.
Pull the tape measure out the desired width. Mark the place on the floor with a chalk mark [source: Carter].
Calculate your hypotenuse with the help of an online calculator, by inputting your desired length and width. Record the result.
Measure a straight line between the two chalk marks. This is called the hypotenuse [source: Miller] or diagonal. If you measured accurately and your building is in fact, square, the hypotenuse/diagonal will match the result arrived at with the online calculator.

Here's how to check if an existing structure is square:

Put the measuring tape at the corner where the two walls meet, and measure three feet (91.44 centimeters) along the length of the area. Mark the place on the floor with a chalk mark.
Put the measuring tape at the corner where the two walls meet, and measure four feet (121.92 centimeters) along the width of the area. Mark the place on the floor with a chalk mark.
Measure a straight line (i.e. the hypotenuse) between the two chalk marks. If the hypotenuse is five feet (152.4 centimeters), the structure is square. [Video Insert Place Holder]