Borrowing from the effusive Sally Field, “You like me! You like me!” I am just cresting 3,000 views in one year (I assume this is good) and, turns out, the subject of doors is the most popular view to date! Following your lead, this post covers basic installation techniques for interior doors.
Door installation is as much an art as a skill. Rarely is the rough framing into which the door is placed square, plumb or level. In remodeling, this can be due to settling and movement of the house over time; on the other hand, in all the time I worked as a trim carpenter in new construction, I never saw a framer (the guy who builds the walls) use a level or a plumb bob to ensure the walls and door openings were not leaning, twisted or shaped like a trapezoid.
In new construction you begin by assessing the rough opening. The rough opening is the hole in the wall built by the framer where the door will be located.
Measure the inside width of the opening from stud to stud, top, bottom and middle. This dimension should ideally be about one half-inch to one inch larger than the width of the door in its frame (jamb.) You will need this extra space to place shims in order to square up the door so it will operate perfectly. Measure the outside width of the door frame (jamb) from the outside of the hinge jamb to the outside the latch jamb to check the door width. These vertical jambs are also called “legs.” You should have a 1/4″ – 1/2″ gap all the way around if everything is sized correctly.
Measure the height of the rough opening; this number should be a bit taller than the overall door height (Remember: “door” refers to the door slab hanging on its hinges inside the jamb or frame. This is referred to as a “pre-hung door.” We’ll discuss hanging a replacement slab in an existing jamb later…) The top piece on the door jamb is called the “header.”
Go get your levels. For door installation close is close enough, so if the bubbles are intact and there are black lines on either side of the bubbles, your level will work fine; we’re not building a boat here, as they say. An assortment of 2-foot, 4-foot and 6-foot levels will come in much handier than one of those 6-inch levels which fits neatly in your tool box but is about as much help in hanging doors as a one-armed wallpaper hanger.
Levels should be accurate; the best way to ensure accuracy is to spend a little more for a good set. Keep in mind the maxim about tools: You get what you pay for.
Set the pre-hung door unit aside and just work with the rough opening for the moment. Place the 6-foot level vertically on the hinge side of the rough opening; get rid of any protrusions like nail heads, staples and dried drywall mud so the level sits flush with the stud. Note whether the surface is plumb (straight up-and-down.) If it’s plumb…Frank Lloyd Wright built the house. Use cedar shims to space the hinge jamb away from the rough opening the distance you measured earlier.
The shims are wedge-shaped; put them together to make flat surfaces to go against the stud and the jamb. Nail the shims to the stud at the same heights as the hinges on the door. They will stick out on both sides; you will cut them off later.
If the stud is not plumb, arrange the thicknesses of the shims to make a plumb surface (the shims) to attach the door jamb to. This is where the wedge shape comes in handy. Use your level to find plumb after installing, say, the top set of shims, then fit the correct thickness of shims between the stud and the level at the other end. That makes the middle set easy to fit. Now you have a plumb surface to fastened the hinge jamb to.
Now you are ready to put the pre-hung unit in its hole. Man-(or woman-)handle the door into the rough opening. This is easiest done with the door closed and secured by a plastic or wood “bolt” through the lock set hole into the jamb hole. Some pre-hung doors come with a screw or nail through the jamb header or leg into the door edge; make sure you find and remove these first to save time and aggravation.
Align the outer edges of the hinge jamb to the wall surface on each side. Drive one nail through the stop (the small board the door closes against) at the top hinge location, through the shims, pinning the door frame to the stud. Now you can operate the door to see how to adjust it during installation for perfect operation. I usually add one more nail towards the bottom, not through the shims, to add stability and ability to make adjustments in the door geometry.
Align the latch jamb with the wall surfaces; “capture” or hold it in place with shims top, middle (behind the latch bolt hole) and bottom friction-fitted between the jamb and the stud. You will adjust these (see below) for proper gap, a.k.a. the reveal, around the door so it’s even, not too large, and not too snug. Kind of like Goldilocks’ porridge, but different.
Close the door. What? You didn’t take out the temporary bolt yet? Okay. I’ll wait…
Close the door. Gently. Does it “clunk” pleasantly when it hits the stops, hitting the stops all the way around? Yes? Nail it all off and go take a smoke break if you live in Colorado. Or Amsterdam.
Does it hit the stop at one place but not uniformly around the perimeter? To fix that, nudge the jamb legs in and out, top and bottom until the door hits the stops all the way around. This will put the jamb either sticking out past the wall surface, or a little behind the wall surface. You will deal with this when you trim out the finished door with casing. Welcome to my world.
Now you can think about seriously nailing the two legs through the shims. Before you put all 6 X 3 = 18 (yes, 18) nails in the jamb, start with one through the jamb at each set of shims. Remember the gap? If it’s uneven when you close the door and exam it all the way around, pry the jamb away from the shims to adjust it until it’s a consistent 1/16″ to 3/32″. Too large will A. look ugly; B. transmit more sound and drafts; and C. look ugly. Too small will cause the door to rub and bind. Adjust shims accordingly for a perfect fit.
You may notice the reveal at the top is a pie-wedge, i.e., uneven. Adjust the shims behind the bottom hinge, adding thickness or taking it away to even up this gap. This technique rotates the door slab to change that gap. You might need to tweak the middle hinge shims to compensate for the bottom movement. The bolt holes in the slab and the latch jamb should now be aligned.
Finish the installation by installing the remaining nails: Three at each shim location, one each side of the stop and one through the stop. If the header (remember the header?) is bowed up or down, shim and nail where it works to get rid of the bow. Use the 2-foot level to check.
One more potential issue you may face in installing an interior door is a sloped floor over the width of the rough opening. Use one of the shorter levels to test this before you begin. Lift up the low end of the level, center the bubble and estimate the amount the floor is out of level across the opening. This will be the distance between the bottom of the level and the floor on the low side with the level level. Using a saw, neatly cut off this amount of wood from the bottom of the jamb leg on the high side. This will compensate for the slope. I do not recommend cutting the bottom of the door to match the slope of the floor; this is difficult to do neatly, and only draws attention to the slanted floor. No one looks at the bottom of the door anyway…
Okay, enough for now. Later we’ll get into a few more tricks and tips that will make you the Dior of Doors.
Oh come on! Fashion IS Art!
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