It is fairly easy to frame an exterior door opening. However, an important step in framing an exterior door opening is knowing how to measure and place the king and jack stubs which are essentially the min frames of your exterior door.
Step 1 – Measuring King Studs
A king studs is the frame that runs through the entire length of the wall. Basically, it is like the main wall frames except that it is used to support and frame doors or windows.
To measure the length of your king studs, all you need to do is measure the length between the sole plate and the wall top plate. Sole plate is the frame located near the floor while the top plate is the upper most frame that is often times found right near the ceiling.
Step 2 – Marking the King Studs
Marking the appropriate location as to where you need to place the king studs is fairly easy. All you need to do is measure the exterior door you will install. This will give you a general idea on how much space is needed for your opening. Add 6 inches to the length of your exterior door.
Step 3 – Installing King Studs
If you do intend to install new king studs in the event that the existing wall studs are not suitable, measure the height from the sole plate up to the top plate. The sole plate is the bottom frame while the wall top plate is the frame on the top most part of the wall. With a saw, cut a 2x4-inch piece of lumber. The height should be the different between the sole and top plate.
To install the king studs, insert it on the door opening and nail it diagonally. Make sure you use a level to ensure that the king studs are level.
Step 4 – Installing Jack Studs
Once you have erected your king studs, you can then install the jack studs. Measure the height of your door adding a 1-inch allowance. This will be the height of your jack studs. Cut the 2x4-inch lumber using this measurement. To install the jack studs, nail along the king studs, making sure that they are level as well.
Step 5 - Measuring and Marking Headers
You can now proceed to measure and mark the locations for your headers. A header is like a beam over the door to support the weight above. Measure the width of the door frame and cut the lumber with this measurement. Be aware of the local building code you need to follow when installing your header.
For a non-load bearing walls, you can use the 2x4 lumber. For a load-bearing wall, use two large lumbers gluing ½-inch plywood in the middle.
Once your header is done, place it on top of the jack studs. Nail it to the jack studs, and then nail it diagonally to the king studs. Again, use a level to make sure everything is perfectly aligned.