Door Jamb Secrets - Using Extension Jambs

Installing a door can be a difficult and daunting task, for most homeowners or even novice contractors. Installing the door correctly, can make a big difference on how long the door will take, before it actually starts rubbing against the door jamb.

Professional door hanging advice can only be given out by people who have dealt with and solve these problems in the past and now know how to prevent them in the future. I would like to share one of these building secrets with you today.

What is an extension jamb? It's a piece of wood that can be nailed on one side of the door jam, to make it a little longer, if necessary. Here's an example of what I'm talking about: you go down to your local home improvement center and buy a pre-hung door and the doorjamb width it is 4 1/2 inches wide.

This doorjamb is made for a 3 1/2 inch wide rough framed wall, with one sheet of half inch drywall on each side, giving us a 4 1/2 inch wide wall, that the new doorjamb will be covering.

Now what if, you're going to be using a 2 x 6 wall or a 2 x 4 wall with 5/8 inch drywall on each side or a 2 x 4 wall with plywood on it and then half inch drywall on each side. Your standard doorjamb will now need to be wider and this is the purpose of an extension jamb.

Install the door even to one side of the wall and then you will install the extension jamb on the other side of your new doorjamb. If you need to add 3/8 of an inch, simply cut a 3/8 of an inch strip, the length of the two sides of your doorjamb and the top headpiece and fastened them, using finish nails or staples.

The real secret here, is knowing which side of the door jambs to apply the extension jamb strips to. Always apply the extension jamb strips to the opposite side of the door hinges. This tip is worth its weight in gold and I hope that you always remember this. If you ever apply the extension jambs to the same side as the door hinge, you'll find yourself having problems opening the door all the way.