Create a Roof

Roofs are added to individual levels, and each level can include multiple roof types, such as flat roofs, single-pitch, double-pitch and hip roofs. In modelling terms, a roof functions as an unconditioned zone when it's set as a cold roof. If a warm roof is selected—typically with insulation at the roof line—it’s treated as a tempered or conditioned space, depending on whether a ceiling is present. This distinction affects how the roof contributes to the building's overall thermal performance.

Add a Roof

Add a Cold Roof

To add a roof, start by selecting Levels on the left and choose the level you want to work with. Click ‘Add Roof Geometry’ followed. Turn on the Layers for the zone you’re adding the roof to so you can use it as a guide. Then, select the ‘Add Roof’ icon and draw the roof zone.

Make sure every node in the zone below has a matching node in the roof zone to avoid any geometric errors. Once you’ve completed the roof outline, give the zone a Title and click ‘Save’ to finalise it.

Add a Warm Roof

A warm roof places insulation above the roof structure, helping to keep the entire space below conditioned or tempered.

To add a warm roof, go to Levels on the left and choose the level you want to modify. Click ‘Add Roofs’ followed by ‘Edit Roofs’, then select the roof you want to nominate. Navigate to the ‘Cavity’ section, set the Insulation Position to ‘At Roof Line (Warm Roof)’, and choose your Outdoor Air Method, applying the preferred air change rate. Click ‘Save’, and you're all set!

Specification

Layout

Layout defines how the roof is configured, including the Roof Type and Roof Offset. The roof type determines the overall shape, such as flat, single-pitch, double-pitch, or hip roof, with additional options depending on your selection. The roof offset allows you to raise the roof line directly from the base level.

Pitch

Pitch refers to the steepness of the roof surface. You can set this using the Slope Method, which defines how pitch values are calculated; Heading, which indicates the direction of the slope relative to true North; Roof Height, which sets the peak height of the roof; and Ridge Offset, which controls the ridge location in double-pitched roofs.

Cavity

Cavity describes the space between layers in the roof structure. While several elements may exist within a cavity, the main adjustable input is the air change rate, defined in Air Changes per Hour (ACH), which influences the thermal behaviour of the roof space.

Eaves

Eaves are the overhanging edges of a roof that extend past the building’s exterior walls, providing protection from rain. Eaves can be defined as a standard projection in metres. If more precise control is needed, custom eaves can also be drawn directly on aspects for finer detailing.

Envelope

By default, all roofs are assumed to be insulated at the ceiling line, creating an unconditioned zone above. However, the Envelope options offer flexibility for adjusting thermal performance by allowing you to set values like Total R-value and Solar Absorptance.

Insulated Surface

The Insulated Surface is the main roof surface designated for insulation. It typically inherits the settings defined for the overall roof envelope, but these can be overridden if needed for specific roof configurations.

Enclosure Surface

The Enclosure Surface is used to close off cavities within the roof structure. For cold roofs, it represents the outer roof shell. In warm roofs, this may instead represent the internal ceiling surface, depending on how the insulation is positioned.

External Ceiling

The External Ceiling is optional and allows you to define a separate surface to represent ceilings exposed to external conditions. If this is not specified, the insulated surface will automatically be used in its place.