Menu Path
Mod-Roof > Dormer
Single Slope and Barrel dormers are specialised dormer types that create unique roof forms.
Single Slope (or 'skillion') dormers have a single slanted roof plane:
while Barrel dormers have a curved, cylindrical shape:
To create these dormers, you'll need to access the Mod-Roof > Dormer creation tool and select either Single Slope or Barrel from the dormer type options.
🧾 Single Slope Dormer Parameters
When you select a Single Slope dormer, you'll see the following configuration options:
Parameter | Description |
Type of dormer | The style of the dormer - select Single Slope from the options (Gable, Hip, Single Slope, or Barrel) |
Pitch | The pitch of the dormer planes |
Distance to Dormer Centre/Distance to Edge | Toggle function: Either the distance along the eave to the centre line/ridge of the dormer from the flashing point, OR the distance to the eave edge of the dormer (with width measuring from this edge) |
Setback from eave | The distance from the eave to the face of the dormer |
Dormer Width | The width of the dormer |
Length | The length of the Single Slope dormer |
Side Overhang | The eave overhang on the sides |
Front Overhang | The overhang of the gable end |
Gap width | The width of the gap created from the face of the gable to the eave (or to a distance from the eave based on the Gap Offset setting) |
Gap Offset to Eave | The distance from the eave to the gap |
Dormer Material | The material category for the dormer planes (Metal, Tile, Shingle, Low Slope, etc.) |
Eave Type | Select from Fascia and Gutter, Gutter Only, Fascia Only, or None |
🧾 Barrel Dormer Parameters
When you select a Barrel dormer, you'll see these configuration options:
Parameter | Description |
Type of dormer | The style of the dormer - select Barrel from the options (Gable, Hip, Single Slope, or Barrel) |
Distance to Dormer Centre/Distance to Edge | Toggle function: Either the distance along the eave to the centre line/ridge of the dormer from the flashing point, OR the distance to the eave edge of the dormer (with width measuring from this edge) |
Setback from eave | The distance from the eave to the face of the dormer |
Dormer Width | The width of the dormer at the base |
Height (Bulge) | The height of the barrel at the centre line |
Side Length | The length of the straight projection of the dormer. This toggles to Height of Dormer Gutter if you want to fix the dormer by height instead |
Front Overhang | The overhang of the gable end |
Gap width | The width of the gap created from the face of the gable to the eave (or to a distance from the eave based on the Gap Offset setting) |
Gap Offset to Eave/Offset from eave to gap | The distance from the eave to the gap |
Dormer Material | The material category for the dormer planes (Metal, Tile, Shingle, Low Slope, etc.) |
Eave Type | Select from Fascia and Gutter, Gutter Only, Fascia Only, or None |
💡 Understanding Toggle Functions
The Distance to Dormer Centre/Distance to Edge toggle lets you choose your preferred measurement method:
Distance to Dormer Centre: Measures to the centre line or ridge of the dormer
Distance to Edge: Measures to the eave edge, with dormer width extending from this point
For Barrel dormers, the Side Length parameter can toggle to Height of Dormer Gutter, allowing you to define the dormer by height rather than projection length.
🔧 Finalising Your Dormer
Once you've configured all parameters, click [OK] to insert the dormer. When you create a dormer, a hole is automatically created in the affected roof plane. The width and projection of the dormer define the size of this hole.
Important: The actual roof coverage equals the hole size plus the eave and gable overhang amounts.
⚠️ Making Changes
If you make a mistake and want to change the dormer configuration, select Undo and start the process again.
🛠 Gap Width Feature
The Gap width parameter creates spacing from the face of the gable to the eave, which can be used to create architectural features like "pigeon roosts" - small recessed areas in the roofline.