Sometimes you just need a new door. If you want to make your life a bit more comfortable by adding a solarium, a screen house, or perhaps a deck right next to your kitchen, you may need an access doorway to make it practical to use. That door will have to be installed within an outside wall of your home.
You might have previously installed interior doors around the house in the past. Exterior door installation is a different game, since you’ll now have to consider structural alterations to a weight-bearing wall of the building, the removal of some insulation, multiple exterior layers such as sheeting, vapor barriers, furring strips, and siding, or possibly even bricks.
It's very important at this point, therefore, to seriously consider all of your options and possibilities.
1. Assess Best Location
When you start doing alterations to the walls around the house, you should always rely on one tool to help you figure out what is behind that drywall in front of you.
A reliable electronic stud finder will provide you with the means to find out what lies inside the wall, where the framing or studding is located, or if there are live electric wires or some water pipes inside there before you actually start your saw and drive it in the wall.
The use of a stud finder can therefore avoid extensive repairs and damages.
1.1 Decide on the Size of the Door
Consider both the maximum and the minimum size of the door that would be practical for your purpose. If you go for a sliding patio door to access a solarium, you'll need a much wider opening than if you install an ordinary swinging door, and you might also want to provide wheelchair access which also has specific guidelines.
With such criteria in mind, you can establish a more accurate picture of the largest as well as the smallest possible door that will accommodate your needs.
1.2 Consider Possible Locations
Standing in the room, look at the wall where you need to cut the door opening. Is there a section on that wall where the largest option would fit without altering the existing layout? Windows, cupboards, wall fixtures, etc., can be relocated without adding too much to the cost.
An HVAC unit, an electrical entrance, a fireplace or a chimney, etc., on the other hand, could require more expensive and extensive work and more probably professional expertise.
With that in mind, choose a section of the wall best suited for the door, and mark the wall (with painter’s tape for instance) for the largest door that can fit there. If it’s too narrow for the smallest size door that you previously figured out, consider what can be shifted or removed and if you’re willing to go with it.
If not, you might have to consider another location for that wall or find another alternative to get around to the other side.
1.3 Get a Feel for What’s Inside the Wall
Once you’ve selected a general area of the wall best suited for the door, take your stud finder, set the adjustments for the thickness of the sheeting on top of the studs, and placing it directly against the wall surface, slide the tool horizontally from one end of the planned surface area to the other end, tracing a mark with a pencil to indicate the center of each and every stud behind that wall.
With that done, before you put your stud finder away, you should scan the complete surface area of where the door is going looking for live wires and for metal pipes inside the wall.
Any such finds will light up a warning light on the screen and generate a sharp warning sound from the tester. If you decide to proceed anyway with the project, make sure to switch off the circuit breaker for that live line and shut off and drain the water line(s) inside that wall.
2. Preparing the Location of the Exterior Door
2.1 Decide How You’ll Frame the Opening
This is when you have to pinpoint the exact location for the installed door, how you plan to frame the rough opening, which ones of the studs will have to be removed, which ones will have to be cut shorter into “cripple studs” above the header, and where new King studs and trimming studs will be added.
FYI Note: A door frame opening is built in a very specific manner for sturdiness and rigidity.
- First of all, a well-fitting King stud is inserted between the bottom plate and the top plate of your wall frame.
- Secondly, a wide doubleheader has to be installed between the 2 King studs at a height of at least 1 inch higher than the finished height of your door, to accommodate the shims, adjustments, and insulation.
- Finally, a jack or “trimming” stud that will fit snugly from the top of the bottom plate right up to the underside of the header in the previous step has to be installed and secured to the King studs. The distance between the 2 Jack studs should be between 1-1/2 to 2 inches wider than the finished width of the door, here again for shims, adjustments, and insulation.
It is very unlikely but possible that 2 of the existing studs could be used as King studs. Most likely you can start at one end with an existing stud, add 1-1/2 twice for the trimming studs and 1 inch twice for the gap on each side for adjustments and shims ((1.5 x2) + (1 x 2)) or 5 inches, then add those 5 inches to the finished width of your door to obtain the net distance at which the inside edge of the next King stud will stand.
Example 1 - Distances with Tolerances between King Studs
You have a door with a finished net width of 36 inches:
36” + (1-1/2” x 2) + (1” x 2) =
36” + 3” + 2” =
41 inches which is the exact distance clear between the two King Studs.
2.2 Tracing the Door Layout on the Wall
Working from the first stud that you chose to start from, go to the mark of the inside edge and punch a finishing nail through the drywall until you find the exact spot where the framing ends.
Draw a vertical plumb line from that hole, all the way from the bottom to about 6 inches higher than the full height of the door, and punch a hole through the drywall with the same nail but at the other extremity of the line drawn. If the nail lands inside the hollow part of the wall, keep punching through at intervals until you reach the stud.
Trace a solid visible line at that spot and using the 36-inch door in example #1, add 1 inch on each side for the shims and trace another solid line at 38 inches.
Drop a plumb line on the wall at that 38 inches mark, and run again about 6 inches higher than the full height of the door.
You should now join those 2 vertical lines by tracing a horizontal line across at about 7 inches higher than the full height of the door. The extra height should provide enough space to install a header between the King studs.
2.3 Exposing the Wall’s Framing
From each of the 2 vertical lines drawn in step 2b, draw 2 more lines parallel to the previous lines and 1-1/2 inch inside of the door opening. These new lines should also run from the floor up to the horizontal line at the top of the door.
This will produce a recess inside the wall to where the King stud is, where the trimming stud will be inserted and concealed. It will also prevent unnecessary patching with long narrow strips of drywall after the door is installed, leaving the repairs only on top for covering the header.
Use a sharp retractable blade utility knife and a jig saw or a reciprocal saw to start cutting along the “inside” lines drawn on the wall leaving an incision around the full perimeter planned for the door. At this point, only the drywall or top layer on the wall should be cut leaving the studs, wall plates, headers, and sills untouched. Cutting the drywall can be finished with your utility knife, especially over the framing lumber.
With this done, use a pry bar to remove all the sheeting from the wall and leave you with a wall of vapor barrier and insulation. Remove the vapor barrier.
Before removing the insulation, you should put a new blade in your retractable knife and finish cutting through the full thickness of the insulation along the full perimeter of the door opening. This is to prevent the insulation from tearing inside the wall leaving spots lacking insulation.
Proceed to remove the insulation and reveal the inside of the wall and its framing.
3. Framing the Door Opening
3.1 Installing the King Studs
Wherever a new King stud needs to be installed, measure the exact length between the top plate and the sill plate and cut a stud to that exact length.
Insert the stud in its place and secure it to the floor and top plate by toe-nailing it in. That will work even better if you use screws instead of nails as it will for one thing provide an easier reach at the top inside the wall.
Repeat the procedure on the other side of the opening if you need a second King stud in place.
3.2 Getting the Door Header Ready
Any exterior wall that stands on the foundation sill can be considered load-bearing, so any exterior wall you intend to cut through to install a door is very likely to be a load-bearing wall.
So how do you know how big to build a load-bearing header? The rule of thumb is to measure the span of the opening in feet and add 2 to that number. The header is built by superimposing 2 pieces of lumber while installing them on edge.
Example 2 - Calculating Header Size
Since the span between the 2 King studs is 41 inches:
Translating 41” into feet = 41 / 12
Giving you in feet a span of 3.42’ or a number of 3.42
Adding 2 to the number 3.42 = 5.42
Since a 2 x 6 is roughly 5-1/2” wide
You’re safe to build your header from doubled 2 x 6s
The bottom edge of the header is part of the door opening frame that the door frame itself will be attached to. It is therefore to be installed at about 1 inch above the door frame.
Draw a perpendicular line on each King stud marking the location of the header. The length at which the cripple studs should be cut is the remaining distance up to underneath the top double wall plate minus the net width of the door header.
3.3 Cutting the Cripple Studs to Length
You now have a bunch of studs that need to be sectioned and removed from the central area of the door opening. The top section of each of those studs will, however, remain in place to be used as cripple studs. The cripple studs are just very short studs that stand in between the top edge of the header and the underside of the double top plate.
Their length is calculated by measuring the distance from the perpendicular line drawn on the King stud in section 3b (to mark the bottom of the header), right up to the underside of the top wall plate.
From that measurement, subtract the width of the header. You can now transfer that new dimension to every one of the studs that need to be cut by tracing a perpendicular line across it.
Make certain that you put on safety eye-wear and a particle mask, and use your circular saw and/or your reciprocal saw to cut each of those studs at the same length and into cripple studs. This will allow the short pieces to sit properly on top of the doubled header once it is installed.
3.4 Securing the Header into the Door Opening
Once the cripple studs are cut to their finished length, the first piece of the doubleheader is placed against the corner formed by the end of the cripple studs and the outside sheathing and secured to each cripple with 3-1/2 inch screws.
Each end of that first piece can then be screwed into each of the 2 King studs. The 2nd piece is then added to it to be again fastened securely in the same manner. The bottom edges of the double header should line up close to the mark drawn in step 3b.
The trimming studs are installed next to ensure sturdy and reliable support for the header despite any kind of weight that might come from above.
3.5 Installing the Trimming (Jack) Studs
The 2 trimming studs can finally be cut to their exact length to fit between the door header and the bottom sill plate and properly support the header. They’re placed directly on the King studs to which they are nailed or screwed in. Your door opening is now completely framed.
You still have, however, the sill plate running across the opening on the floor. The reciprocal saw will provide the perfect solution to removing the extra length of the bottom plate, by bringing the blade next to the trimming stud and going down on the bottom plate with it.
Once one end is severed, move to the other trimming stud and start over. The floor plate can then be pulled off with the pry bar.
4. Opening Up to the Outside
At this point, the door opening is completely framed and practically complete except that it is still closed to the outside by the exterior sheeting, siding, bricks, etc.
Your completed frame will permit you to mark exactly where to cut the material from the outside and avoid sizing mistakes. It will also let you cut across the top of the door at the right height without risking a cut too high or too low requiring further extensive work later.
4.1 Outlining the Perimeter Outside
From inside the room, take your drill, and with a long wood bit no more than 3/8 inch diameter, drill 2 holes, one at each of the top corners demarcated by the frame, right through to the outside. If, however, the wall cladding is bricks, you might have to finish with a concrete drill bit.
Also, keep in mind that the accuracy of your outline on the outside cladding of the house will only be as accurate as your ability to maintain the drill bit in a perfectly perpendicular positioning with the wall.
With the positioning of the 2 top corners of the door opening now demarcated at the top, go down to the bottom of the opening up against the trimming stud and repeat the drilling on each side of the opening. With the 4 corners of the rectangle established, use chalk or a marker pen and trace the contour of where the wall will need to be cut through.
4.2 Removing the Exterior Wall Cladding and Sheeting
The exterior wall cladding can be made of a multitude of different materials from vinyl siding, aluminum siding, wood and wood fiber, fiber cement, natural stone, clay or concrete bricks, etc.
Once the outline is marked all around its perimeter, you can cut vinyl with a utility knife and tin cutters- also used to cut aluminum, to cut wood, or various by-products with reciprocal and circular saws, and stone along with concrete with a saw equipped with a carbon blade.
No matter the material or the tool used, the sheeting and cladding are all removed to free the opening with this last step and all that’s left to do is to install the new door in the wall.
There are many more articles on our site related to this piece, including "Rough In Size for a Pre Hung 32" Door", "How to Seal an Exterior Door", and "How to Make an Exterior Door Jamb."