Doors and Windows - Door Height from floor

How high off the floor should an interior door be? My prehung door is an 1" higher than the jambs. Can I set the jamb on the floor and go or does the whole unit need to be shimed up? I will be laying carpet. Thanks!

An inch will usually work, unless you are using an unusually thick carpet pad and thick carpet. Check to make sure the floor is level where the door will be swinging- sometimes if the floor is out of level, it will be fine when the door is closed, but as you swing the door back, the gap might start to get tighter!

Generally, you don't worry about it and the jambs go right against the floor. If the door drags on the carpet later, you just trim the door off so that it clears the carpet by 1/4" or so.

It seems that I have the opposite problem. It seems that my door is about 1 3/8" off the floor and I will be putting down laminate flooring. Therefore, it would seem that I could trim the jambs down somewhat to avoid too large a gap under the door. Given that the floor is level, what would be the minimal gap between the finished floor and the door and what would be the potential problem associated with trimming the jambs?

Thanks in advance.
Stefan

You could, but the door may appear odd in relation to the other doors (casing & hardware locations).

The term is "undercut". Deliberate foreshortening of the door slab, (the length is measured from the top of the slab), to accommodate flooring, threshold, and swing clearance.

Wood door manufactures establish their own standard undercut. Typical valves are 1/2" and 5/8". 3/4" and 1" are common for some. 5/8" will accommodate most carpets. On a stable level floor a 1/4" swing clearance, the thickness of a wooden yardstick), will suit most conditions. Not true, in some instances when higher air volumes must be moved.

Doors can be ordered with any desired undercut.

I'm not absolutely certain, (factory error, hacked by someone, shipped to the wrong locaiton), but an 1-3/8" undercut is indicative of a door made for installation on the sub-floor with hardwood flooring applied. If carpeted afterward minimal trimming would be required.

To avoid this problem in the future either order doors with the desired undercut or measure the slab before purchase. 6/8 = 80" minus flooring thickness, threshold (if any), plus swing clearance allowance = undercut, deducted from 80.

To solve your own problem, measure the side jamb length and to the center of the latch bore from the top of the slab. Compare them with your other doors. It's a simple "box" problem with fixed postions.

Hardware locations, even when specified from the floor, are measured from the top of the slab, because it's a reliable constant. You can live the variation or you can't.

Jerry solution: add a block & kickplates & paint.

Thanks for the response. When I ordered the doors, I was not aware of any "undercut" size specification. Right now, I have no other doors in the basement, so uniformity should not be a problem as I would do the same to each door. The door will be install with the jambs on top of Dri-Core subfloor, which is about 3/4" above the slab.

My next step is to do what you recommended, "measure the side jamb length and to the center of the latch bore from the top of the slab. Compare them with your other doors." If I'm comfortable with dropping the location of the door knob with reducing the undercut, then I will go ahead and do that. I will also think about whether or not someone would want to install carpet and account for that as well.

Again, thanks for the response.
Stefan

Most prehung residential interior doors are a standard 80" in height and the jamb legs are longer to accomodate the eventuality of the different flooring options available. Allowing you to adjust the height above the floor.