How To Install A Split Jamb Pre-Hung Door

Split Jamb Pre-Hung Doors

Hanging a split jamb pre-hung door is a very easy home improvement project. We ordered all the doors for our new house at the same time, including the basement ones. The basement doors have been sitting in the basement in the original packaging for over a year now. So I decided it’s time to get the basement organized, so today I hung a couple of the doors in the basement.

As you can see the doors in our new home are all six panel colonialist textured hollow core doors. We ordered them all with 2 1/2″ primed colonial casing. When you buy a split jamb pre-hung door you need to know what type of casing you’ll be using. As you can see in the second photo the front and back casings are attached to the two halfs of the jamb (hence the split portion of the jamb).

Installing Split Jamb Doors

The first step is to take apart the frame. This is done by simply pulling the front molding and jamb away from the back molding and jamb. As you can see in the photo there is a slot in the main jamb that accepts the back jamb. The door is already attached to the main jamb with hinges.

Once you remove the jambs you’re ready to hang the main jamb with the door. Place the jamb and door in the rough opening (I’m assuming you already have built the rough opening, this example is a 2-6 door (30″) so the rough opening is 2′-8 1/2″ wide, typically you add 2 1/2″ to the opening width).

You’ll want to position the door in the opening and try to square it as best you can. Place a level on the top and sides to make sure the door is level and plumb. In this example I’m installing a door in a storage room, so there is only drywall on the hall side. I’ve installed some 1/2″ shims between the door casing and the wall framing to make up for the lack of drywall. Once the door is level and plumb then you can attach it using some 10d finish nails. You nail directly through the casing into the wall framing.

The next step is to work from the other side of the door. Now all you have to do is install the remaining split jamb. In the photo below you can see the door from the hall side with the slot that accepts the remaining jamb. All you do is simply slide the other jamb into the slot and slowly work it together until it is tight up to the finished wall. Again nail the casing with 10d finish nails and you’re finished.

The only thing left to do is install the door knob set and strike plate. If your rough opening is the correct size and you have all the tools you’ll need this project will take approximately 10 minutes from start to finish. So next time you’re buying a pre-hung door and you know what the casing will be I suggest you look into a split jamb pre-hung door. The time savings is great and it really saves on trimming out the door.

Related posts:

1. How To Install Bifold Doors
2. How To Trim Pocket Door Jambs
3. How To Install Pocket Doors
4. EZ-HANG™ Door Installation System
5. Colonial Style Fluted Window & Door Trim

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