The curved lines of arched framing create a unique look on interiors and exteriors of homes. Homes that have square openings can be easily converted to arched openings if the arch is properly designed and constructed. Framing an arch requires a bit of knowledge in geometry and mathematics, and only requires simple tools for design and layout. Arched framing is usually not considered structural and relies on the stability and properties of the structural framing members hidden behind the arch.
Determine the width of the arch by measuring the framing opening.
Place the 48-by-48 inch pieces of plywood on a set of sawhorses and align the ends of the two pieces on top of each other.
Place a screw in each corner of the plywood pieces to hold them together.
Measure the distance of the header from the ceiling. The header is the structural framing member over a door opening.
Place a mark at 24 inches on the plywood.
Mark a line by placing the 48 inch level parallel to the edge of the plywood on the 24 inch marks.
Measure parallel with the 24 inch line from the top of the plywood and mark the dimension previously measured for the distance from the ceiling to the header.
Add 1 1/2 inches to the mark for the distance from the ceiling to the header and mark it on the plywood below the header mark.
Divide the width of the framing opening dimension in half.
Extend the tape measure and place the end of the tape measure at the 1 1/2 inch mark that was previously placed on the plywood.
Measure the divided width of the framing opening from the 1 1/2 inch mark and place a mark perpendicular on the 24 inch mark. These intersecting marks are the pivot points for the arch.
Place the level on the intersecting mark and draw a line across the plywood, intersecting the 24 inch line.
Drive a 4-penny nail in the centre of the intersecting marks.
Hook the end of the tape measure on the nail and hold the pencil on the dimension that matches the divided framing opening width.
Pull the tape measure and pencil around, holding the pencil on the same dimension. This forms an arched line. The line should intersect the 1 1/2-inch mark and be extended down the plywood to form a line for the sides of the opening.
Use the power saw to cut the plywood on the line that intersects the 24 inch line.
Use the jigsaw to cut the arched line.
Place the arched pieces on the wall framing by placing the arched side toward the bottom and the square side tight against the ceiling.
Fasten the pieces of arched plywood on each side of the framing with 1 inch drywall screws.
Cut the 2-by-4 to lengths to fit between the plywood arch. Most walls are 3 1/2 inches, so the 2-by-4s should be cut to 3 1/2 inches.
Align the face of the 2-by-4s with the bottom edge of the arch and fasten them through the plywood on both sides with 1 inch drywall screws.
Fasten the 2-by-4s around the entire arch.
Using a fine tooth jigsaw blade will allow a for a smooth radius cut.
Wear safety glasses to reduce the risk of eye injury.