# How to calculate the arch

Arch - decorative ceiling in the building. Today, the arch design is a great solution for decorating design apartment, house or garden. It arches solve many problems, including the installation of the door, which is not necessary in the case of the arch, the expansion passage, etc. In order to correctly and beautifully, efficiently and reliably construct arched ceiling, you need to know some important details, including the calculation and from whom, and will depend on all further work. Masters professionals to quickly and easily produce all the calculations, but what to do when work is done on their own, how to calculate the arch and that it should be aware of?

## Instruction how to calculate the arch

Step 1:

Determine the actual place where the arch will be installed, measure the height and width of the opening, and define the height of the arch rise. As a rule, the height - it is 10% of the width of your door or interior doors opening.

Step 2:

Take a sheet of plywood or drywall, draw a line equal to the width of the opening, which we shall call A and B. Mark the middle of the segment AB, it will be a point of L. Swipe through the middle point of the perpendicular. This would coincide with the perpendicular your central axis of the opening (point C).

Step 3:

Connect the points A and C, and the resulting split AC segment in half, getting a point D. Through the point D is another perpendicular to its intersection with the axis of the opening. Put there a point E.

Step 4:

Spend EA arc radius. Spend between AB and semicircle line exactly in the middle, calling it H. drawing is ready.

Step 5:

The radius of a circle arch for the school get the formula: R = (L² + H²) / 2H. Calculating and knowing the radius of the arch height of its rise (the width of the board), go to the calculation of the maximum possible length of the parts that must be cut out of the width of your board. Perform the calculation using the following formula: L = √2RH - H²̚

Step 6:

You should know that for the manufacture of your arch parts should be slightly larger than those obtained in the calculation since they will have to join together, overlaying. Before we cut directly to the arched structure, it makes sense to make a template and try it, so you avoid mistakes and get ready for cutting the pattern of your material - wood or drywall.

Step 7:

There is also a simplified version of the calculation. Note the height of the arch above the door and add to the level of 5-7 cm. You get the height of the arched opening. If the resulting height is greater than the height of the door, you have to peck. But the building itself arches scheme so that all angles are equal and the circumference have still using formulas.