Two story house, but roof only placing on first floor.

[andeale08]

I'm in my drafting 3 class in my high school with some other students. We are creating two story houses based on previous drawings that we drew. When we attempt to put a roof on the second floor, it becomes a roof on the top of the first floor and goes through everything we have on our second floor. We've only been working with the program for a little while so if anyone knows how to add a roof that will be on the top of the second floor and could reply to this, it would be greatly appreciated. Thanks!

[Steve_Stafford]

Hello, welcome! I've moved your post to the more appropriate forum.

When you make a roof you can either start in a view associated with the correct level or change the assigned level via the properties of the roof while sketching or after finishing the roof. Since you've finished the roof already, just select it, edit properties and change the level assignment to the correct level. If you don't have a level for the top plate of the second floor wall framing, you either need on or can just use and offset value from the second floor level.

Good luck!

[mlgatzke]

Unfortunately, Revit does not understand one of the important dimensions used in the construction of a residential roof truss or rafter. The offset height that Revit provides does not correlate to any actual dimension used in the production of a roof.

I don't know how in-depth your teacher has gone with you about the construction of a residential roof, but if you're trying to be "dead-on" accurate with the height of your residential roof, you can generate the roof at any offset. Then, create a section at a location through the roof that you can use to raise the roof. Simply move the roof to reflect the appropriate "heel" height required.

The heel height is the dimension measured vertically along the surface of the exterior sheathing and goes from the top surface of the double top-plate to the top surface of the top chord of the truss (or rafter). In my region of the US (Midwest), winter conditions are harsh and insulation is very important, so we require a minimum of an 8" heel to allow for the necessary insulation. You may not understand what a "heel" height is, but it's a very important part of the calculation for a roof used by roof truss manufacturers.

Just ignore if you're not looking to be "that" accurate. However, it's something to keep in mind for future use.

[patricks]

Unfortunately, Revit does not understand one of the important dimensions used in the construction of a residential roof truss or rafter. The offset height that Revit provides does not correlate to any actual dimension used in the production of a roof.

Actually, it does. You just have to know how Revit creates the roof based on different input.

Isn't a typical rafter-framed roof made by cutting a notch out of a 2x rafter and placing it on the top plate so that the lower edge of the rafter intersects the inside edge of the double top plate? If you create the roof by selecting the walls with Extend to Core checked, specify an overhang distance, and then pick Rafter for the roof type in the properties, then it will make the roof so that the bottom surface of the Roof's core layer precisely intersects the inside face of the wall's core layer. That is how I made the roof in the attached image. The offset of the roof is shown as zero, which is how it should be.

Consequently, if you change the roof to Truss, it moves up to put the bottom edge of the roof's core layer directly on the outer face of the wall's core layer. This would correspond to a roof truss with extended rafter tail ends that extend down below the bottom chord of the truss. If you sketch a truss roof by picking walls and specifying an overhang, but you pick the outside faces of the walls (Extend to Core left unchecked), then Revit will put the underside of the roof's core layer on the very outer edge of the outside finish face of the wall.

If you wanted a truss where the width of the truss includes the overhangs (no extended rafter tails) then you would need to sketch the roof with just lines offset however much your overhang is. That puts the very lowest edge of your roof at the same level as your top plates, which would correspond to a bottom truss chord running across the tops of the walls.

To the original poster: Our template has 2 levels to start with: Level 1 ground floor and Roof. What I would do for a 2-story house is move the roof up to the upper-most bearing height (the top of your 2nd story walls) to keep your roof plan looking right, and then create a new level for your second floor. Then go to your roof plan, and when you create the roof it will be created on the roof level and should be at the top of your 2nd floor walls.

[andeale08]

Thanks for the help everybody! We are being very successful now!