Do your homework before replacing a door; carefully check the condition of all the components. Any problems with the hinges and jamb must be resolved before measurements are taken for the replacement door.
Before installing a new door into an existing jamb, it is important to check the condition of the hinges, jamb and door. Any problems with the hinges and jamb must be resolved prior to measuring the dimensions of the replacement door. When a door opening is in good condition, the jamb is plumb and the opening is square. If a standard door uses standard hinges, there should be approximately 1/8" along the hinge edge and 1/8" along the lock edge. If the door uses a continuous hinge, use the manufacturer's suggested dimension for the hinge side of the door. There can be an additional 1/16" for jamb irregularities. The door should have approximately 3/16" to 5/8" undercut at the floor. The undercut will vary depending upon the installation.
Before replacing a door, consider why the door is being replaced. If the door is damaged, where and how did the damage occur? Was the damage the result of and accident, corrosion, or wear? The answer can usually only be determined by examining the door, the hinges and the opening.
When asked, most customers will describe the result(s) of door problem(s), not the door's problem(s). You will have to determine the cause of the problem(s) and the solution. For example, the customer tells you the door drags on the threshold, or the door will not close properly. These are not the actual problems; they are the results of the problems. The actual problems could be that the building has settled, the jamb has moved out of position, and/or the hinges are worn. Realize that there can be more than one reason for the doors' problem(s).
EXAMINE THE OPENING
When examining a door and the opening, the first step is to try opening and closing the door. Does the door swing freely? Does the door latch and close completely? Look closely along the edges of the closed door. Is the door square with the jamb/threshold at the top, sides, and bottom? Is there sufficient space between the door and the jamb/threshold? Is the jamb out of square? Is there excessive clearance along one or more of the door's edges? Inconsistent clearances on a given side of door can be the result of an out of square or twisted jamb, or improperly seated or worn hinges.
One problem can be that the threshold lifts, which causes the bottom of the door to drag over the raised portion of the threshold. Tightening the threshold fasteners can properly position the threshold in the door opening.
Note: If this solves the problem, use thread adhesive or new fasteners to ensure the threshold stays in place. If not, look further.
If the door does not properly fit the opening, the problem could be the building has settled or was racked in an earthquake. Walk around the building and look for evidence of damage. This can include cracking on the exterior, and window and door frames that are no longer level. Depending upon the degree of settling, door replacement may be just a temporary fix.
Another problem is worn hinges. Examine and tighten all of the screws in all the hinges. Replace any missing screws. If any of the screws do not tighten, depending upon the jamb material, install longer or larger screws. Lubricate the hinges. Open and close the door. Do the hinges function smoothly? Is the door swing level? Are there missing or worn pieces of the hinges?
The heavier and wider the door, the greater the amount of force is placed on the hinges. This can cause the hinges to wear and eventually cause problems. Should the problem be worn hinges, obtain the proper hinges for the height, width and weight of the door. If the door opens out, use non-removable pin (NRP) hinges to prevent unauthorized access.
Next, examine the jamb to determine if there are problems. Door problems can be the result of problems with the jamb. Check to see if the jamb is securely mounted into the opening. Grasp different sections of the jamb and try twisting. If the jamb moves, it needs to be secured to the opening. Is the jamb square within the opening? Use a large framing square to check for square. Then measure the opening diagonally, top left to bottom right and top right to bottom left. The two measurements should be just about the same.
Is the jamb plumb? Placing a level against the three parts of the jamb can determine if the header is level and the jamb is plumb. Place a weight (Plumb Bob) attached to an approximate six-foot string letting the weight hang to determine if the jamb is plumb. Has the jamb twisted? Open the door and look at the jamb in comparison to the opening. Place a straight four foot or so long board or four foot steel rule against the jamb. If there is twisting, the jamb will appear uneven. Measure the opening to be certain it is just as wide at the top, middle, and bottom. Measure the opening from the header to the floor at the left, middle, and right to make certain the opening is of equal lengths.
Make any needed repairs prior to measuring for or installing a new door.
MEASUREMENTS
When measuring for a new door to be installed into a jamb in good condition, considerations must be made in two areas: the type of hinge being used, and some additional space for jamb irregularities.
If the door is being installed is standard, no wider than 3'6" or heavier than standard using standard hinges, approximately 1/8" should be adequate space between the door and the header. There should be about 1/8" on the latch side of the door and 1/8" on the hinge side of the door. Add an additional 1/16" for jamb irregularities to the sides. Depending upon the application, the door undercut should normally be 3/16" to 5/8".
TYPE OF DOOR
Before measuring the opening, know the type of door being installed. Is the door hollow metal, finished wood, or unfinished wood? An unfinished wood door can be machined to compensate for an uneven jamb. Finished wood and hollow metal door are difficult to machine to compensate for an uneven jamb.
Start by measuring the width of the door near the top, middle, and bottom of the jamb. Look at the three numbers. If they are close, consider using the smallest dimension. Take this number and subtract approximately 5/16" for the door to jamb dimensions including jamb irregularities.
To compensate for slight irregularities, spacers can be placed behind a hinge to compensate. If the irregularities are larger, the jamb must be repaired to ensure the door fits properly.
Measure the height for the door near the left, middle, and right sides. Again, look at these numbers and if they are close, consider using the smallest dimension. Remember you need to know the size of the undercut. This dimension will determine the size of the door. Take the measurement and subtract from approximately 1/2" to 7/8" for the header to threshold dimension including irregularities.
Before ordering a door, discuss the dimensions with the door company. They may have specific criterion when ordering a particular type of door or using a specific type of hinge or continuous hinge.
In future articles, we will discuss temporary door repairs, door replacement, time of delivery, when to replace the jamb, wood versus metal, and a list of door companies.
