Setting Up the Main Roof in Revit for Residential Design

Adding the roof to a residential Revit model involves creating a new working plan view, tracing the building footprint, and defining which edges carry slope. The roof by footprint tool gives you control over where ridges, hips, and gable ends form based on which sketch lines have slope applied. Understanding how slope assignments affect roof geometry is key to getting the shape you need on the first try, or at least understanding why the result looks the way it does so you can adjust it efficiently.

Creating a Working Plan for the Roof

The first step is to create a new floor plan at the second floor top plate level. This plan will not necessarily appear on any sheet, but it provides a clean view for building the roof footprint. From the View tab, select Plan Views and then Floor Plan, and choose the second floor top plate level. The resulting plan will initially appear empty because the view range settings default to showing only elements at that level. Adjusting the bottom of the view range to "Unlimited" and the view depth to "Level Below" brings the walls below into view, providing the outline needed for tracing the roof.

Before starting the roof, hide any unnecessary elements in this view, including CAD imports, setback lines, and property lines, so the workspace is clean.

Using the Roof by Footprint Tool

From the Architecture tab, click Roof to activate the Roof by Footprint command. The Pick Walls option allows you to trace the building outline by clicking on each wall, and an overhang value can be set in the options bar. For a typical residential project, a two-foot overhang is a common starting point. Select the roof type you want to use such as a wood rafter with asphalt shingle, and begin picking walls to trace the footprint.

As you pick walls, Revit organizes the sketch lines and joins them at corners. If a line appears on the wrong side of a wall, clicking the flip arrows will move it to the correct position. For areas where the roof shape differs from the wall layout such as a pop-out over an entryway, you can switch to the Draw Lines or Pick Lines tool to create custom sketch lines at the desired offset.

How Slope Assignments Create Roof Geometry

The Define Slope toggle is what determines the roof shape. When slope is applied to two parallel edges, a ridge forms at the midpoint between them. When slope is applied to perpendicular edges as well, 45-degree hip conditions appear at the corners. Edges without slope defined produce gable ends.

It is important to check the slope value every time you define slope on a new edge. Revit may default to a steeper pitch like 9:12 when you expect something like 4:12. Setting the slope in the Properties panel before finishing the sketch prevents unexpected results. If the roof geometry looks wrong after finishing, you can always edit the footprint, adjust slope assignments, correct the pitch values, and finish the sketch again.

Adding a Secondary Roof Section

Residential projects often require more than one roof plane. For example, an entry canopy or a lower roof section over a single-story portion of the house needs its own roof element. This is created using the same process: start a new roof by footprint from the working plan, draw or pick the footprint lines, and define slope on the appropriate edges.

Secondary roof elements may not automatically appear at the correct elevation. After creating the roof, switch to an elevation view to see where it sits relative to the main roof. The move tool can be used to reposition the secondary roof by snapping its endpoint to the correct location on the main roof, creating a clean intersection between the two planes.

Attaching Walls to the Roof

Once the roof is in place, walls can be attached to it so that they extend up to the underside of the roof rather than stopping at their default height. Select one or more walls (using the CTRL key to add to the selection), then click Attach Top and pick the roof. This fills in gable ends and cleans up the transition between walls and roof in the 3D view. Multiple walls can be attached in a single operation, including walls that are partially obscured in the current view.

Saving and Moving Forward

After the main roof geometry is established and walls are attached, save the project before moving on to cleanup tasks. The garage area and any remaining roof transitions typically require additional adjustments, which can be handled in subsequent steps as the model continues to develop.