Site icon Concord Carpenter

How To Replace an Exterior Door


Replacing an Exterior Door

Replacing an existing exterior door with a new pre-hung door is a fairly straightforward task. In most cases you measure the old door and try to get a new door the same size.

When measuring and ordering a new door there are four things you need to know:

1. Door size:

Measure the width and height of your old door. Round these up to full inches to find the size of the replacement door you’ll need. If, for example, your door measures 35-3/4 in. wide and 79-1/2 in. tall, you’ll order a 36-in. by 80-in. door.

2. Jamb width:

Measure the existing door jamb. To do this, measure from the backside of the interior trim to the backside of the exterior trim You will want to match this width with your new door. This measurement ensures that the interior trim will fit flush to the wall without adding “jamb extensions.”

3. Rough opening:

This is the distance between framing stud to framing stud and rough sub-floor to the top header. Remove the interior trim to get accurate measurements for the rough opening.

4. Door Swing:

The easiest way to determine which way a door swings is to put your backside against the hinge jamb and swing your arm to follow the door open. the door is either a left swing or “left hand” swing door or a “right hand” swing door.

5. Trim Measurements:

When ordering a door you need to consider the exterior trim style and size. sometimes I will measure for and specify the width from exterior trim edge to edge and bottom exterior sill to top trim edge. I do this when the siding may make it necessary to have the trim exact. this measurement can sometimes be accomplished by the door company when they assemble the door.

The alternative to this is to order the door without trim and then apply it after the door is installed.


Photo: Southern gentleman, Baker and Finish Carpenter George Gussler
Nothing was standard about this wall opening, floor or trim. so I measured for the door and jamb size and filled in the rest.

Pre-hung doors need to sit on a level surface. The first step is to make sure the threshold sub floor is level or to shim it level if it’s not.

The door I ordered had a larger jamb size to accommodate for the lath and plaster in this old house.

Rubber Vycor flashing protects the sill and edges from the weather. Flashing extends behind the granite step.

The door was plumbed in the opening and installed along the outer edge or the house sheathing. Shims were installed at the hinge locations and similar locations on the latch side. I also add solid shimming near the deadbolt.

The door was secured to the shims with galvanized 16 penny finish nails. We try to hide most of the nails behind the weatherstripping. Others get filled.
Air sealing with minimal expanding foam is next. We use the foam to seal all around the doors edge.

Exterior trim was then added. We used pvc for the bottom piece under the threshold for two reasons; one it resists rot and two it resists takes a beating, unlike wood, from people kicking off their boots in the winter.

The install was finished by adding a Larson storm screen combination door.

Subscribe here to receive updates via email

↑ Grab this Headline Animator

If you enjoyed this post, make sure you subscribe to my RSS feed!
Exit mobile version