A rough door opening is the space cut out of a wall where the door will be eventually mounted. In technical terms the rough opening is a structural frame which will surround the door unit. The rough opening measurements of width, height and depth are larger than the actual finished door size, to allow for the door and its frame after installation. This extra room leaves sufficient space to make allowances for the door jambs (vertical frame pieces) that support the door, clearances and any leveling necessary for proper door functionality. Measuring proper rough openings is a crucial part of the planning for a project, as the door placement will not only impact the overall room design and layout, but it can help you to avoid costly on site adjustments.
Key Measurements for Interior Door Rough Openings
Fortunately, calculating rough door opening measurements is not particularly complicated, but it does vary according to the type and style of the door.
- Single Doors: The rough opening for single doors is 2 inches wider and 2.5 inches taller than your actual door size. As an example, if you have a door that is 36” x 80”, you would need a rough opening of 38” x 82.5”
- Double Doors: If you have double doors, you will need to have a rough opening that is 2 inches wider than both the doors combined, plus the standard 2.5 inches in extra height. So, if you have a set of two 30” x 80” doors, you’ll need a rough opening of 62” x 82.5”
The exceptions to the above include custom or non standard door sizes. If you are creating a wheelchair accessible door, you will require a minimum of 32 inches clear width, being the actual open space someone can pass through when the door is fully opened. This calls for a 34 inch door and a 36 inch rough opening width. There are also other specialty doors such as laundry rooms that often require a wider opening.
Allowance for Variability
There are a number of factors that will affect your rough door opening measurements. These include:
- Flooring: You will need to account for any new flooring such as carpet or hardwood that will alter the height requirement for your rough opening.
- Wall Thickness: Your choice of wall material will have an impact on the depth jamb sizes, since the frame will need to be thicker to accommodate thicker walls.
Understanding How Doors Are Labeled
Doors are typically labeled with a combination of numbers that indicate the width and height in feet.
For example,
- 2-0 (20): 2'0" wide or 24 inches wide.
- 2-6 (26): 2'6" wide or 30 inches wide.
- 2-10 (210): 2'10" wide or 34 inches wide.
Heights are similarly labeled:
- 6-8 (68): 6'8" tall or 80 inches tall.
- 8-0 (80): 8'0" tall or 96 inches tall.
Calculating Rough Openings for Door Installation
To translate your door size into the rough opening size, you need to add 2 inches to the door width and add 2.5 inches to the height. Just remember to include the frame and clearance into your calculations. So, a 2-8 / 8-0 door, with a height and width of the door and frame of 32 inches x 96 inches, which requires a rough opening of 34 inches x 98.5 inches.
It is a good idea to measure the width at multiple points, which will help you to account for any framing irregularities. You should measure the height from the subfloor, including allowances for the flooring, leveling and door frame.
You will need to bear in mind that if you have settling or warped walls, you will need shims to create proper alignment. This will mean you’ll need some additional space in your rough opening calculations.
ADA-Compliant Spacing and Clearances for Rough Openings
For ADA- compliant doorways, the finished doorway must offer at least 32 inches of clear width, being the open space a person can pass through when the door is fully opened. This means that for standard drywall and jamb configurations, you will need a rough opening width of 36 inches.
The rough openings for accessible areas also need to allow for clear space on either side to ensure maneuverability. There should be clearance beside either side of the door to accommodate sufficient wall framing for wheelchair access, offering at least 48 inches of usable floor space in front of the door. You need to consider rough framing that will allow for adequate depth of a full door swing and a turning radius. So allow more space in your rough opening if the door will have a wider swing.
Impact of Rough Openings on Room Layout and Design
Rough openings provide the opportunity to see what space is required for proper door placement in your design. For example, if you’re arranging multiple doors from a common hallway, rough openings show how much more space is needed compared to simply looking at the actual door measurements.
In fact, many designers don’t appreciate the space requirements for proper door placement. If they have never hung a door or watched one being framed on a jobsite, they could be prone to making planning errors, which will require changes during the construction process.
While it may seem like a simple thing to just switch to a narrower door, this could compromise the flow of the room or make accessibility a challenge, particularly for wheelchair users or those with mobility issues.
Special Considerations for Different Door Types
While the measurement guidelines we’ve included here apply to most doors, there are some special considerations if you opt for a different type of door.
Double Doors
If you have double doors, you will need to have a rough opening that is 2 inches wider than both the doors combined, plus the standard 2.5 inches in extra height. So, if you have a set of two 30” x 80” doors, you’ll need a rough opening of 62” x 82.5”
Sliding Doors
You will need to measure stud to stud to allow for the frame size and sliding mechanism rather than just the door size. Once you have this measurement, add the same 2 inches x 2.5 inches additional space.
Pocket Doors
The rough opening size for pocket doors is twice the door size plus one inch in width and the door height plus two inches.
Bi-fold Doors
There is no hard and fast rule for bi-fold doors as the rough opening size will vary. Generally, you will need to allow one inch more than the combined width of the door panels and two inches more than the door height to allow for the track system. However, it is a good idea to check the specific recommendations for your chosen door system before creating your rough opening.
High Traffic Areas
In busy spaces, for ease of use and increased durability, you are likely to have more robust framing. This means that the frame will be wider than standard, which will add to the overall width of the rough opening.
Conclusion: Rough Openings as the Backbone of Functional Design
Rough openings are not just a measuring part of the project. They represent a critical intersection between design and construction. Improper rough opening sizes can lead to uneven door swings, misaligned casings or even creating structural strain in a load bearing wall.
Builders and project managers are increasingly favoring a larger rough opening to accommodate thicker drywall and provide the opportunity for wider casing options. This will allow clients to choose traditional or modern designs when they select door trims.
Well planned rough openings are not only important functionality but also provide flexibility for future renovations or accessibility upgrades. With care and precision today, you can potentially avoid costly fixes tomorrow.