However, our friendly passerby would see consistent widths of overhangs on all sides. In this option, the rafter length would have to change–the rafters would be longer at the brick-faced wall, and shorter at the siding-faced wall. The overhang dimension is one foot, zero inches on all sides. Now the option box is unchecked, and the overhang measurement is taken from the exterior finish face of the wall. Now let’s look at the other option: Do not extend into wall (to core). This is measured from the exterior face of the wall’s studs, telling us that the Extend into wall (to core) option was checked. The wall section above-right, which by the way is from my recently-published book, Residential Roof Design using Autodesk Revit, shows an overhang of one foot, six inches.
The second option (if the box is unchecked) means that the specified Overhang dimension will be measured from the exterior finish face of your wall, out to the rafter ends. The first option (if the box is checked) means that the Overhang dimension that you set (say, eighteen inches) will be measured from the exterior face of the studs out to the ends of the rafters. Let’s clarify what the two options (checked and unchecked) mean. The words in the Option Bar are not as self-explanatory as they could be. When you create a roof in Revit using the Select Walls tool, in the Options Bar, you will see an option with a checkbox (see the left, red-colored arrow in the image below). This post explores the effect of different types of wall finish materials on the overhang of the roof. For example, the situation might call for brick on the front face of the house, and a less expensive material such as siding or stucco on the sides and rear. Often, builders or owners will specify that a house will have different wall materials on different sides of the house. One big advantage of this parametric relationship between the wall and the roof is that the overhang can be controlled easily by changing the settings in the properties box and the options bar. The Pick Walls tool justifies and constrains the roof’s edge to the supporting wall below. See the red arrow to the right in the image below. Primary among these tools is the Pick Walls tool, which is available when you are in Sketch Mode and you are creating the edges of the roof footprint. Revit gives us some great tools for creating and modifying roof overhangs. I’m assuming the use of wood framing and rafter-type roof construction. In this post, I’m speaking about residential projects, such as a single-family home. A wall section from my new book, Residential Roof Design using Autodesk Revit