By default the whole roof will be sloped.
Low slope roof in revit.
Select the lines of the roof outline and right click over the line.
When in the roof by footprint sketch mode select all of your newly created boundaries and turn off the defines slope parameter.
A roof cannot attach to another roof and the roof cannot be a curtain roof.
To create a slope for an odd shaped roof like the one below use slope arrow.
See hd version of video tutorial here.
This create an uni directional slope parallel to the arrow.
To specify roof pitch select a slope defining boundary line click the numeric slope definition.
The second option in the list is toggle slope defining.
Check variable material in the roof structure to create sloped insulation.
The roof assembly is defined as the roof deck along with the roof membrane and roof insulation.
Flat roof in revit this one is very straightforward.
The insulation thickness must be at least as thick as the vertical slope else you will receive a warning.
8 set variable material for sloped insulation.
In order to enable shape editing tools the following conditions must be met.
Low slope roofs are often referred to as flat roofs.
In sketch mode select a roof boundary line that defines slope indicated by.
Floors must be flat and on a horizontal plane.
Roof assemblies with a pitch slope of less than 3 12 are considered low slope roofs.
To construct a flat roof you must toggle the slope defining line see step 3.
The tail is the low point and the head is the high point.
For a low slope roof you can change these to inch rise to 12 inch run by clicking the roof outline and replacing the slope dimensions.
Revit will issue a warning when a slope significantly deviates from the expected thickness.
Finish the sketch by pressing the green tick and you will not have a completely flat roof surface in your revit model.
On the properties palette select or clear defines roof slope.
Draw the arrow then click it and change the properties to select the right levels and offsets.