Roofs (12:18 min)

Exercise 1–Add Roofs

There are a couple ways to make roofs in Revit. Footprint roofs are very similar to floors. Extrusion roofs are sketched a little differently offering some alternative roof shapes. Let’s try both.

Catch-up file completed to this point: 12_Medical Center_Roofs.rvt

Add a Footprint Roof

We’ll need two footprint roofs, one for each of the brick portions of the building.

  1. On the Project Browser, double-click to open the Level 2 floor plan.
  2. Zoom in on the left side of the building.

This portion of the building is one story tall, so we will build its roof on the second floor level.

  1. On the Architecture tab, on the Build panel, click the Roof by Footprint tool.

Most options are identical to floors. We have the Boundary Line and Pick Walls tools active. We sketch the shape of the roof’s footprint in plan. Just like floors. However, by default, Roofs default to sloped roofs. This is controlled by the “Defines Slope” checkbox on the Options Bar. For this building, we need mostly flat roofs. But we can use the slope feature to make a simple slope for drainage (see Figure 12–1).Leave Defines slope checked for now.

Figure 12–1 The default options for the Roof by Footprint tool

  1. Click on the vertical wall near Grid 1 on the left. Zoom in near the middle of the sketch line after you click.

Notice that the line went to the outside of the wall. But there is a flip control.

  1. Click this to flip the line to the inside face of the wall (see Figure 12–2).

Figure 12–2 Flip the sketch to the inside face of the wall

  1. Zoom back out and move around the plan and click once on each wall that you want to use for the sketch (see Figure 12–3).

After flipping the first edge, the sketch lines go to the inside face of the walls.


Figure 12–3 Create the sketch boundary

  1. Finish the roof.

It will look a little odd in the Level 2 plan. This is because the roof is currently sloped on all sides and is being cut by the floor plan’s view range.

  1. On the Project Browser, double-click to open the {3D} view (see Figure 12–4).


Figure 12–4 The roof defaults to being sloped all the way around

  1. Select the roof, and then on the Modify | Roofs tab, click the Edit Footprint button.
  2. Dragging from left to right, make a crossing selection through all of the sketch lines except the original line along Grid A.
  3. On the Properties palette, uncheck the Defines slope checkbox.
  4. Select the remaining line (the one along Grid A).

This will deselect the other lines leaving only this line selected.

  1. Click on the slope control onscreen (currently it reads: 9″ / 12″). Type in: 1/4 for the new slope and then press enter to accept it (see Figure 12–5).


Figure 12–5 Turn off slope for all but one edge, then change the slope value

  1. Finish the roof.

You will now have a simple flat roof with a gentle slope.

We can repeat the process to create a flat roof for the middle portion of the building. We can continue to work directly in the 3D view for this if you like. Or if you prefer, open the Roof floor plan.

  1. On the Architecture tab, on the Build panel, click the Roof by Footprint tool again.
  2. In the “Lowest Level Notice” dialog, choose: Roof from the list and then click Yes (see Figure 12–6).


Figure 12–6 If you create a roof in the 3D view, you will be prompted for the level to which to associate it

  1. On the Options Bar, uncheck Defines slope this time.
  2. Click the six walls that make up the upper portion of the building.

Make sure the inside edges are being picked. If you can’t tell in 3D, open the Roof plan view to verify. Flip any edges that require it.

  1. Click the Modify tool to disable the pick walls tool.
  2. Select the line along the back wall (the one on Grid D in plan).
  3. Toggle on Defines slope and set the slope to: 1/4 as before (see ).


Figure 12–7 Set the slope of just the back edge

  1. Click the Finish Edit Mode button. Study the results in other views if you like (see Figure 12–8).

Figure 12–8 The slope can be seen nicely in section view

Creating a Reference Plane

For the atrium portion of the building, we will create a custom shaped roof using the extrusion roof tool. We need to start with a reference plane. Reference planes are essentially guidelines that will help us locate the sketch and set the depth of the roof.

  1. Open the Roof plan view.
  2. On the Architecture tab, on the Work Plane panel, click the Ref Plane button (or press rp).
  3. Click a point to the left of the atrium (between Grid 8 and 9) and about halfway between Grids J and K.
  4. Move the mouse horizontally to the right and click the other end past the outside of the building.
  5. Change the value of the temporary dimension between Grid K and the reference plane to: 10'-0".


Figure 12–9 Draw a reference plane parallel to and in front of the building

  1. Cancel the command, select the new Reference Plane and then on the Properties palette, in the Name field type: Atrium Roof (see Figure 12–9).

Reference planes are similar to grids and levels except they have no restrictions on orientation (they can be drawn in any direction) and then don’t have annotation. Use them as work planes for geometry.

Creating an Extrusion Roof

To draw the extrusion roof sketch, we must work in a view parallel to the work plane (our new reference plane in this case).

  1. Open the South elevation.
  2. On the Architecture tab, on the Build panel, click the Roof drop-down button and choose: Roof by Extrusion (see Figure 12–10).

Figure 12–10 The Roof by Extrusion tool prompts for work plane and level

  1. In the “Work Plane” dialog, from the Name list, choose: Reference Plane: Atrium Roof and then click OK.
  2. In the “Roof Reference Level and Offset” dialog, accept Atrium Roof and zero and click OK.

Zoom in near the bottom-right side of the elevation at the exterior wall on the right.

  1. Click the first point of the sketch at the endpoint on the outside of the right-most exterior wall (tab if necessary).

Roll the wheel of your mouse down to zoom back out before clicking the second point.

  1. Move the mouse up well beyond the top of the building and slightly to the left of Grid 10.
  2. When the angle reads 94°, click to place the second point. Press esc once to break the chain but remain in the sketch (see Figure 12–11).


Figure 12–11 Create the first sketch line angled from the far right wall

On the Draw panel, make sure that the line tool is still active.

  1. Click the first point about 5'-0" to the left of Grid 9.
  2. Move down and to the right past the right side of the building and click when the angle reads 6° (see Figure 12–12).

Figure 12–12 Draw a second line along the top of the atrium also at an angle

  1. Use Trim/Extend to Corner to join the two diagonal lines to one another (see Figure 12–13).

Figure 12–13 Trim the corner to complete the sketch

  1. On the Mode panel, click the Finish Edit Mode (green checkmark) button.
  2. With the new roof still selected, on the Properties palette, for Rafter Cut, choose: Two Cut – Square.
  3. Edit the Extrusion End to: 70'-0" (see Figure 12–14).

Figure 12–14 Adjust the properties to complete the roof

Attach walls to Roof

Let’s cleanup the connections between the walls and the roof.

  1. Delete the Generic - 12" wall on the outside of the atrium.
  2. Select the three curtain walls in the atrium. (It is easiest to do this in the Level 1 plan view using the ctrl key).
  3. On the Modify | Walls tab, on the Modify Wall panel, click the Attach Top/Base button.
  4. Click the extrusion roof we just created.

An error will appear indicating that mullions cannot be created. This is expected as we are cutting the shape of the curtain walls to match the slope of the roof. It is safe to click the Delete Elements button here.


Figure 12–15 Some mullions must be deleted for the curtain wall to adjust to the roof slope

  1. In the error dialog, click the Delete Element(s) button (see Figure 12–15).

When you do this, the curtain walls will be unacceptable. Large portions disappear. There is an easy fix to this.

  1. Undo the previous command.
  2. In the Level 1 floor plan, select the extrusion roof and move it to the right slightly about 2" is plenty.
  3. Repeat the attach top/base command.

This time it will work much better (see Figure 12–16).

Figure 12–16 The first attempt to attach the curtain walls to the roof yields poor results - after moving the roof, it works much better

  1. Add one more footprint roof above the small vestibule. Associate it to Level 2, use the Overhand option with a value of about: 1′-0 on the three exterior sides and a slope of about: 2″ / 12.
  2. When you finish the roof, it will prompt to attach the walls to the underside, answer Yes (see ).


Figure 12–17 Create a small roof over the vestibule