Door Basics

Locksmiths service door locks. If the door is equipped with a closer, be it surface mount or concealed, locksmiths service door closers. Locksmiths adjust door hinges so the door can close. Why not install doors? They can be a very profitable option...

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Check the lock hardware to make sure it is in operating condition. If the lock hardware is in operating condition, it can be installed into the new door.

Use a plumb line to determine that the door and the frame are plumb (in vertical alignment). Take a carpenter’s square and determine if the frame is square. Also, measure the door diagonally from the top right corner to the bottom left corner and the top left corner to the bottom right corner. These two measurements should be the same or very close.

The next series of steps is to take measurements of the frame. (See Cross Section Door Frame Graphic, page 29.) Most door companies like the measurements in inches and fractions up to 1/32”. Always use a steel rule or steel tape measure when determining the dimensions. The more information provided when measuring the frame can help to insure getting the door having the correct dimensions.

We are using the illustrated sheet “Replacement Door to Fit Existing Frame. (page 27)” This guide indicates all of the measurements required for determining the dimensions of a replacement door. Follow the alphabetic order to determine the dimensions.

The measurements are taken from where the door is when closed. The width of the opening should be measured at the top (A), middle (B) and bottom (C). The reason why there are three measurements, this enables the replacement door manufacturer to determine the appropriate door size for a proper fit in the opening.

The next series of measurement are for the hinge locations. The hinge locations are measured from top of the frame header rabbet to top of hinge. The frame header rabbet is the flat surface adjacent to the soffit where the door enters when closed.

This door has three hinges. The first measurement is from the top of the uppermost hinge to the frame header rabbet (D). The second measurement is from the top of the middle hinge to the frame header rabbet (E). The third measurement is from the top of the bottom hinge to the frame header rabbet (F). These measurements vary amongst the door manufacturers and need to be the proper lengths for the replacement door to fit the opening.

The next measurement is from the frame header rabbet to the top of the strike plate(s) (G). Be sure to include the type of strike plate used i.e. “T” strike or ASA strike. If more than one strike plate is installed, such as a separate deadbolt and latch bolt for this door, you need to measure to the top of each of the strike plates and label each measurement.

The door height should be measured at the left and right sides of the opening. The measurements are from the frame header rabbet to the top of threshold, carpet or finished floor (H). If the dimensions vary include both measurements. If not include the measurement.

The size of the strike plate(s) must be measured (I). For this application, measure the deadbolt strike plate and the cylindrical lock strike plate.

The next step is to measure the hinge height (J). The three hinges should always be the same size. For this door, the butt hinge height will probably be 4-1/2”.

The hinge backset is the dimension from the soffit to the edge of the hinge leaf (K). This dimension is the same for all three hinges.

The frame rabbet size is the measurement from the stop, which is the edge of the soffit to the edge of the frame (L).

Butt hinges can have different leaf thickness. Measure the thickness of a hinge leaf (M). Standard butt hinge thickness for a 1-3/4” thick door is 0.134”.

If there is a threshold, measure the height of the threshold from the floor (N).

The next step is to determine the hand of the door (O).

Most commercial applications will be 1-3/4” thick door. However, always measure the door thickness (P). The door thickness is determined by measuring the distance between the front and rear faces. If a commercial exterior door is less than 1-3/4” thick, order the replacement door at 1-3/4” thick.

Determine if there is a bevel on the lock edge of the installed door. The bevel is the angle of the lock edge of the door. A door that does not have a bevel has a square edge. A beveled door is handed and requires a smaller gap than a square edge door.

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