Installing prehung door - DIY Chatroom

jdhar · 10-06-2009, 07:12 PM

I'm trying to install a prehung door for the first time, and had a basic question.

Everywhere I have read has said that the header jamb should be level, and the hinge jamb as level as possible. I'm assuming then the latch side jamb should also be level if the other two are.

My question is what if the floor is out of level slightly? Articles I have read say to trim the jam accordingly to maintain a level header jamb. But if I do this, won't the reveal on the bottom side (w.r.t. the floor) be uneven by the amount that the floor is out of level? Is this common practice?

My floor isn't that bad out of level, but I have already killed one prehung door trying to do this, and I want to get this one right.

oh'mike · 10-06-2009, 08:11 PM

Hi,Newbe---The first thing to do when hanging an interior door is check the floor for level.

1.Cut a piece of scrap wood the width of the opening,put it on the floor in the opening.

2.put a level on top of the wood.

3.shim the scrap till level.

4.measure the shim height.

5.you must cut the jamb leg on the opposite side by that amount.I.E.;shims on the hinge side?cut on the latch side,-----Shims on the latch side ? Cut on the hinge side.

Yes,the gap on the bottom may be off a bit-however that is much more acceptable than a crooked door!-----------------MIKE

oh'mike · 10-06-2009, 08:20 PM

Shim and nail the hinge side next . Check the reveal at the top ---adjust shims on the hinge side till reveal is acceptable.

Shim and nail latch side.

With heavy doors,adding longer screws(into the 2x4) to the upper hinge is required.

oh'mike · 10-06-2009, 08:41 PM

By the way;If the doorway is to be carpeted,you can skip cutting the jamb---just shim er'up-the carpet will hide the gap.

sausagefingers · 10-07-2009, 12:05 PM

Here's an easy way I hang doors. Just put the door in place, put a nail in each corner at about where the hinges are. Put a level on the header and shim the side of the jamb up accordingly to make it level. Now shut the door, and shim over or knock over the hinge side of the jamb to make the reveal at the top of the door equal across the whole header. Shim and nail the hinge side of the jamb to set it at least at the top and bottom hinge. Now just shim over the other side of the jamb to make an equal amount of reveal down the whole side of the jamb/door. Nail and enjoy.

Willie T · 10-07-2009, 01:10 PM

Click HERE to find this subject in the HOW TO Section

biker · 10-21-2009, 02:14 PM

I understand that the jamb leg needs to be cut but wouldn't that throw off the door knob latch precut hole? I'm doing the same thing and my floor is off ~1/4in. I thought that that alignment may get skewed.

oh'mike · 10-21-2009, 08:26 PM

Cutting the jamb leg will not change the alignment at all.---MIKE

CookeCarpentry · 10-21-2009, 08:53 PM

It will only change the alignment if you cut too much or not enough off. Right now, as it sits, if you did nothing to it, the strike would be 1/4" off.

Also, if the reveal at the bottom of the door is skewed and bothersome, you could always take a set of scribes and scribe the bottom of the door to the floor, then cut and belt sand down to the line. Yes, the door will be skewed, but it may be less noticeable than a skewed reveal.

biker · 10-22-2009, 10:21 AM

Thanks everyone. Much appreciated!