Join Paul F. Aubin for an in-depth discussion in this video How to build a roof dormer, part of Revit: Tips, Tricks, and Troubleshooting.
- [Instructor] In this video I want to walk you through the process of creating a roof dormer. I'm going to show you with a roof dormer like the one we have here, but you could actually use this to join any two roofs together. I've got a completed one right here, and what it takes to make a roof dormer involves having of course a roof. Typically, there's going to be some wall elements that make up the surrounding portions underneath the dormer, and then inside of here somewhere, if I hide these three walls, there's also an opening cut here that cuts the dormer opening into the parent roof.
Let's go ahead and walk through the steps we need. Now, not every dormer is going to require all of those pieces, but many of them will. So anyway, let's look at the essential steps. Now to get us started I have already added these three walls over here. Now those are just walls. You just go up to that floor plan, and you just draw walls like normal. With addition to that I'll go up to the roof plan here, and I'll draw another roof. The roof that I have for this object over here is using a little bit of an overhang in this direction, a slightly larger overhand in this direction.
We'll kind of set it up the same way. I'll go to Roof by Footprint, and I'll use my Pick Walls option. I'm going to go with a one foot overhang, and that will give me the larger distance out at the front here. Then, for the two sides I want to do a smaller overhang, so I'll do half a foot, and I want to make sure that these two edges have Define Slope turned on. Now, I'll select both of these lines, and they're currently set to a slope of nine and 12 but I want to drop those down to a slope of six and 12 which matches the parent roof down below.
Now, the slopes don't actually have to be the same, but you do want to be careful that the ridge of your dormer doesn't go up higher than the ridge of the parent roof, because if it does, when you try and join them together it'll look kind of weird and might not work well. As far as the backside of this roof I'll just simply cap that off by drawing a line, and I don't want that one to be sloped so I'll select it and uncheck Define Slope. So, by only slopping the two sides I'm going to get a little gable condition, and I'll click Finish here.
It will ask me if I want these three walls, which currently intersected, if we want those to join to the roof. I'm going to go ahead and say yes here, but one thing that I forgot to check was the height that I wanted this roof to be. So, what I'm going to do is go to my south elevation here and take a look at that. As you can see it's a little bit too low. Okay, so I'll select this roof here, and the base offset from level is three and a half feet.
It's base level is set to the upper roof. Now, when I click this one the base offset from level is five feet, and it's set relative to the lower roof which is a little bit odd. Let's change this to the upper roof, and let's make this three foot six. Then, when we apply that it'll move up to the same location as the other dormer. Now, you'll also notice that I've got a slightly different eve condition here than what I have right here. So, with this roof selected, if you scroll down you have different rafter cut conditions that you can do.
The choices are Plum Cut, Two-Cut Plum, and Two-Cut Square. So, I'm going to choose Two-Cut Square, and then if you just apply that it's going to look really odd, but then you're able to actually set a fascia depth. For the fascia depth I'm going to do half a foot. So, I'll put in zero space six, and that will now give me the fascia there. You see hot it's actually perpendicular to the roof? That's because I did Two-Cut Square. I actually want Two-Cut Plum and then that will level it off and will make it straight up and down there.
So, now that I've got the roof created, let me go back to the 3D view. The Axon metric here. The next step in the process is to attach this roof to the post roof over here. So, there's a command for that on the Modify tab, and it's called Join/Unjoin Roof. When you run this command, the prompt will ask you to select an edge at the end of the roof that you want to join. So, that'll be either this edge or this edge, and it doesn't really matter which one you pick.
Then, it will ask you to select a face on another roof that you want to join to. Well, that's the sloping face right here. That's all you have to do and the roof will extend back and attach itself to the underlying roof geometry here. Now, if I were to select these elements and hide them, there's no interaction with the underlying roof at the moment. So, the next step is for me to cut a dormer opening out of this roof.
Also, you can see that here I've got the walls joining the roof very nicely at an angle. So, let's select each of these three walls, and when we created the small roof it asked us if we wanted to join geometry to the upper roof up above. That was this command right here, Attach Top and Base. Well, we can do the same thing to attach it to the roof down below. So, Attach Top and Base, it defaults to top.
That's what we did to connect it to this roof. If we choose base and then we pick the roof underneath, then it'll actually cut the bottom edges of those walls, and now you can see that this one is that triangular form, and this one is cut here. Now, they kind of sit right on top of the roof. Now, we've got the walls taken care of, we've got the roof taken care of, so the last step is to cut the dormer opening. I'll go to the dormer opening command, and this will ask you to select the roof that you want to cut with the dormer.
That's going to be this roof. That puts you in a sketch mode, and it will default to pick roof edges or wall edges. I can actually pick on these walls here. Let me press tab to try and get the other side. I'll have to orbit around. There we go. If I pick the outer edges of this, and I make the hole go all the way out to the outer edges like it's doing right now, when I finish, it will generate a warning, because currently the bottom edges are cutting to the roof.
We just did that step. If we cut away a hole underneath, there'll be nothing for them to join to anymore. Let's click the little flip grip, right here, to flip these lines. We click the modify tool here, and flip these lines inside, so that they're on the inside faces of those walls rather than the outside faces. Now, I need to go back to pick edges, 'cause I also need to pick this roof. When you do, that will create that little v shape up at the top. Now, all I have to do is use trim and extend to a corner, and clean this up, and do that all the way around.
You have a nice enclosed shape and click finish. That will cut the dormer out of there. You can see it if you highlight it, but if I just select this roof and isolate it, you can see that opening is cut through. Those are the essential steps that you need to create a dormer roof. Now, I'm going to do one more quick example of this. I'm going to actually delete this roof, leave everything else intact, and I'm going to go to a south elevation and draw the roof in a slightly different shape here using the roof by extrusion.
This will ask me for a work plain, so I'll click okay, and I'll pick this brick wall. I'm going to associate it with the upper roof. I'll just draw a little eyebrow shape like so. Want to keep it below that ridge there. Finish it, and that creates this roof. It's a little odd right now because it's flush with the walls, but to edit that we can do edit profile, and we can just kind of stretch that just a little longer. I'm doing that by eye, but you might want to be a little more precise about that.
If I go back to the 3D here, you can see that it went really deep through the building. Let's just kind of pull it back to about here. Then, let's take this one and pull it out a little for an overhang. There's the basic roof. Now, I'm going to do the join roofs again. Select this back edge, select this surface, and it will join along that curve. Revit doesn't really care whether it's a standard gable roof or whether it's an extrusion roof.
You can use the same set of tools to create these dormers in really any shape you want. I'd still want to come back and rejoin the walls to the underside. I'd want to redo the dormer opening holes so that it follows the curve instead of the straight lines. It would be the same basic steps that we just looked at. Any time you need to join two roofs together, whether it's for a dormer condition or just two sections of the building that need to connect to one another, you can use that join unjoin roof command. Then, if you want, the dormer opening allows you to cut holes in the roof that match the shape of the dormer.
NOTE: The exercise files for this course can only be opened in the most recent version of Revit (Revit 2017).