Dormer

Mod-Roof > Dormer

The Mod-Roof > Dormer command allows you to draw a dormer in one of several styles. The styles available are Gable, Hip, Single Slope and Barrel.

In isometric, the dormer styles appear below:

To create a dormer, click the Dormer command. You are then prompted to select an eave. Selecting the eave also selects the roof plane the dormer will effect as well as the orientation of the dormer. The point at the end nearest where you selected the eave line begins to flash, giving you a point of reference for placement of the Dormer.

Gable and Hip Dormers

The Dormer defaults dialog is then displayed, letting you set the dormer parameters.

These parameters refer to Gable and Hip dormers:

The Dormer dialog, along with many other larger and sometimes more complex dialog boxes, has two modes – a Full display and a Simple display. [More] and [Less] buttons to hide the less used functions of the software until you need them. This cleans the interface up and provides a simple user experience for first-time users.

Type of Dormer This is the style of the dormer which is one of Gable, Hip, Single Slope or Barrel dormer.

Typical hip dormer

Front Overhang This is the overhang of the gable end.
Side Overhang This is the eave overhang on the sides.
Gap Width This is the width of the gap that will be created from the face of the gable to the eave (or more exactly, to a distance from the eave based on the next value).
Gap Offset to Eave Gap This is the distance from the eave to the gap (as above).
Side Style This is the style for the eaves of the gable dormer. “Both horizontal” is the default but you can have “Project left”, “Project right”, or “Project both”.
Dormer Material This is the material category that you want to apply to the dormer planes – Metal, Tile, Shingle, Low Slope etc.
Eave Type This allows you to select the type of eave you want on your dormer, Fascia & Gutter, Gutter Only, Fascia Only & None.
Draw Side Walls? If Yes, then the front and sides of the dormer are drawn also. If No, they are not drawn. You may not want to draw the sides if the dormer projects past the eave line.
Insert at Apex of the hips, or at a position along a hip. See below for a further discussion.
Insert along Hip This lets you insert a dormer along a hip like a flying gable. See below for a further discussion.
Preview This allows you to preview the insertion of the dormer before committing to insert it.

Dormers at Hip Apexes

To insert a dormer wedged at the top of a hip, you first select the “Insert at apex” button, then snap to the point at the hip apex. The dormer is then drawn in preview mode, ready for you to either accept or change the parameters. The dormer dialog box is also changed to display the following parameters.

Here you can change the offset from the eave to the face of the gable and you can change the width. You will notice that these two fields are now toggle buttons.

If you click them, the dialog box is changed to look like the following:

Now you can set the offset to the gable with respect to the base of the higher hip. You can also force the dormer to adopt the width at the face of the dormer from hip to hip. In this way you can use this approach to create dutch gables.

In effect, using this approach, the ridge apex point is fixed in position.

Insert Along Hip

When you click this button you are prompted to locate a hip line, then enter some initial fixing values.

You enter the distance from the eave to the face of the dormer gable. You then enter the distance from the top of the hip to the ridge intersection with the dormer. After you click [OK], the Dormer Defaults dialog box is displayed. Changes you now make to the fixing parameters assume that the ridge apex of the dormer remains in a fixed position.

You would use this approach to create gables on hips much like the Modify Roof > Flying-Gable command.

Single Slope and Barrel Dormers

For a Single Slope dormer, you get the following dialog box.

Type of dormer This is the style of the dormer which is one of Gable, Hip, Single Slope or Barrel.

Typical single slope or ‘skillion’ dormer

Pitch This is the pitch of the dormer planes.
Distance to Dormer Centre/ Distance to Edge This is the distance along the eave to the center line or ridge of the dormer. This is the distance from the flashing point. Alternatively, this is the distance to the eave edge of the dormer and the width of the dormer measures from this edge. The function is a toggle button.
Setback from eave This is the distance from the eave to the face of the dormer.
Dormer Width This is the width of the dormer.
Length This is the length of the Single Slope dormer.
Side Overhang This is the eave overhang on the sides.
Front Overhang This is the overhang of the gable end.
Gap width This is the width of the gap that will be created from the face of the gable to the eave (or more exactly, to a distance from the eave based on the next value).
Gap Offset to Eave This is the distance from the eave to the gap (as above).
Dormer Material This is the material category that you want to apply to the dormer planes – Metal, Tile, Shingle, Low Slope etc
Eave Type This allows you to select the type of eave you want on your dormer, Fascia & Gutter, Gutter Only, Fascia Only or None.

For a barrel dormer, you get the following dialog box:

Type of dormer This is the style of the dormer which is one of Gable, Hip, Single Slope or Barrel.
Distance to Dormer Centre/ Distance to Edge This is the distance along the eave to the center line or ridge of the dormer. This is the distance from the flashing point. Alternatively, this is the distance to the eave edge of the dormer and the width of the dormer measures from this edge. The function is a toggle button.
Setback from eave This is the distance from the eave to the face of the dormer.
Dormer Width This is the width of the dormer at the base.
Height (Bulge) This is the Height of the barrel at the centre line.
Side Length This is 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.
Front Overhang This is the overhang of the gable end.
Gap Offset to Eave This is the distance from the eave to the gap (as above).
Dormer Material This is the material category that you want to apply to the dormer planes – Metal, Tile, Shingle, Low Slope etc
Gap width This is the width of the gap that will be created from the face of the gable to the eave (or more exactly, to a distance from the eave based on the next value).

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Picture shows a good example of the Dormer Gap used to create “pigeon roosts”.

Offset from eave to gap This is the distance from the eave to the gap (as above).
Eave Type This allows you to select the type of eave you want on your dormer, Fascia & Gutter, Gutter Only, Fascia Only or None. When you click [OK], the dormer is inserted.

If you make a mistake and want to change the dormer, select Undo and start again.

When you draw a dormer, a hole is created in the affected plane. The width and projection of the dormer define the size of the hole. The amount of actual roof coverage is the same as the hole plus the amount of eave and gable overhang.

Be creative with dormers

You can be very creative with the settings for the Dormer function and depending on the settings, very different results will be achieved. Take the roof below, where we have added a dormer with the same apparent dimensions when viewed in plan.