The width of an exterior door unit is dependent on three things: configuration, unit construction, and door swing.
The configuration of the unit corresponds to pieces and parts of the unit. If a unit is a single entry door, the width will be much smaller than a triple patio door. The more components used to create a unit will result in a wider unit.
Construction relates to a continuous or boxed unit when referring to doors with sidelites. Most units are continuous, meaning they utilize a single head jamb and a single sill. A boxed until will be constructed of separate units coming together. One of the benefits of a boxed unit is the ability to include mull pockets which makes the unit even wider in the scenario that a standard unit will not fit in the rough opening of the building.
The swing of the unit is the final factor of the unit width as the brickmould sits different on an outswing unit than it does on a inswing unit, resulting in different dimensions.
Component Sizes
While every unit type needs different components, the size of the components are typically the same.
- An exterior jamb measure 3/4″ (in the rabbet).
- An astragal measures 7/8″.
- A standard mullpost measures 1″.
- A fat boy mullpost which is used in venting sidelite units measures 1-1/2″.
- Standard brickmould is 2″.
- Most units also require clearance on the hinge and strike side of a door and this will range by construction type.
Measurement Types
There are four measurement types associated with units.
Unit Dimension (UD) is the measurement of the unit from the outside of the left jamb to the outside of the right jamb.
Brickmould Dimension (BD) is the measurement of the unit including the brickmould from the outside of the left brickmould to the outside of the right brickmould.
Rough Opening (RO) is the unit width dimension plus 3/4″ to account for installation of a unit into a building’s rough opening.
Masonry Opening (MO) is the brickmould width dimensions plus 1/2″ to account for the installation of a unit into a building’s masonry opening.
Continuous Unit Measurements
Below are the components used in each unit configuration as well as the UD, RO, BD, MO.
Single Door
Components:
1 Door
2 Jambs
Clearance
| Based on a 36” Door slab, the width measurements are as follows: | |||
|---|---|---|---|
| UD | RO | BD | MO |
| 37-5/8″ | 38-3/8″ | 40-1/8″ | 40-5/8″ |
Single Door, One Sidelite with Standard Mullpost
Components:
1 Door, 1 Sidelite
2 Jambs, 1 Mullpost
Clearance
| Based on a 36” Door slab and a 12” sidelite, the width measurements are as follows: | |||
|---|---|---|---|
| UD | RO | BD | MO |
| 50-5/8″ | 51-3/8″ | 53-1/8″ | 53-5/8″ |
Single Door, One Sidelite with Fat Boy Mullpost
Components:
1 Door, 1 Sidelite
2 Jambs, 1 Mullpost
Clearance
| Based on a 36” Door slab and a 12” sidelite, the width measurements are as follows: | |||
|---|---|---|---|
| UD | RO | BD | MO |
| 51-1/8″ | 51-7/8″ | 53-5/8″ | 54-1/8″ |
Single Door, Two Sidelites with Standard Mullposts
Components:
1 Door, 2 Sidelites
2 Jambs, 2 Mullposts
Clearance
| Based on a 36” Door slab and two 12” sidelites, the width measurements are as follows: | |||
|---|---|---|---|
| UD | RO | BD | MO |
| 63-5/8″ | 64-3/8″ | 66-1/8″ | 66-5/8″ |
Single Door, Two Sidelites with Fat Boy Mullposts
Components:
1 Door, 2 Sidelites
2 Jambs, 2 Mullposts
Clearance
| Based on a 36” Door slab and two 12” sidelites, the width measurements are as follows: | |||
|---|---|---|---|
| UD | RO | BD | MO |
| 64-5/8″ | 65-3/8″ | 67-1/8″ | 67-5/8″ |
Double Door with Astragal
Components:
2 Doors
2 Jambs, 1 Astragal
Clearance
| Based on two 36” Door slabs, the width measurements are as follows: | |||
|---|---|---|---|
| UD | RO | BD | MO |
| 74-9/16″ | 75-5/16″ | 77-1/16″ | 77-9/16″ |
Double Door with Astragal, Two Sidelites with Fat Boy Mullposts
Components:
2 Doors, 2 Sidelites
2 Jambs, 2 Mullposts, 1 Astragal
Clearance
| Based on two 36” Door slabs and two 12” sidelites, the width measurements are as follows: | |||
|---|---|---|---|
| UD | RO | BD | MO |
| 101-9/16″ | 102-5/16″ | 104-1/16″ | 104-9/16″ |
Patio Door with Patio Mullpost
Components:
2 Doors
2 Jambs, 1 Mullpost
Clearance
| Based on two 36” Door slabs, the width measurements are as follows: | |||
|---|---|---|---|
| UD | RO | BD | MO |
| 74-11/16″ | 75-7/16″ | 77-3/16″ | 77-11/16″ |
Triple Door with Patio Mullposts
Components:
3 Doors
2 Jambs, 2 Mullposts
Clearance
| Based on three 36” Door slabs, the width measurements are as follows: | |||
|---|---|---|---|
| UD | RO | BD | MO |
| 111-11/16″ | 112-7/16″ | 114-3/16″ | 114-11/16″ |
Boxed Units
Below are the components used in each unit configuration as well as the UD, RO, BD, MO.
Single Door, One Sidelite
Components:
1 Door, 1 Sidelite
4 Jambs
Clearance
| Based on a 36” Door slab and a 12” sidelite, the width measurements are as follows: | |||
|---|---|---|---|
| UD | RO | BD | MO |
| 51-1/8″ | 51-7/8″ | 53-5/8″ | 54-1/8″ |
Single Door, One Sidelite, Mull Pocket
Components:
1 Door, 1 Sidelite
4 Jambs, 1 Mull Pocket
Clearance
| Based on a 36” Door slab, a 12” sidelite, and a 1-1/2” mull pocket, the width measurements are as follows: | |||
|---|---|---|---|
| UD | RO | BD | MO |
| 52-5/8″ | 53-3/8″ | 55-1/8″ | 55-5/8″ |
Single Door, Two Sidelites
Components:
1 Door, 2 Sidelites
6 Jambs
Clearance
| Based on a 36” Door slab and a two 12” sidelites, the width measurements are as follows: | |||
|---|---|---|---|
| UD | RO | BD | MO |
| 64-5/8″ | 65-3/8″ | 67-1/8″ | 67-5/8″ |
Single Door, Two Sidelites, Mull Pockets
Components:
1 Door, 2 Sidelites
6 Jambs, 2 Mull Pockets
Clearance
| Based on a 36” Door slab, two 12” sidelites, and two 1-1/2” mull pockets, the width measurements are as follows: | |||
|---|---|---|---|
| UD | RO | BD | MO |
| 66-1/8″ | 66-7/8″ | 68-5/8″ | 69-1/8″ |
Double Door with Astragal, Two Sidelites
Components:
1 Door, 2 Sidelites
6 Jambs, 1 Astragal
Clearance
| Based on two 36” Door slabs and two 12” sidelites, the width measurements are as follows: | |||
|---|---|---|---|
| UD | RO | BD | MO |
| 101-1/2″ | 102-1/4″ | 104″ | 104-1/2″ |