guidance from an expert framer
Nov 2025 – This 15 minute interview was recorded with an expert framer who is leading a team of framers building custom luxury homes in southern Ontario. The topic was how to frame custom barrel dormers into a pitched roof made from manufactured trusses.
FRAMER: Who am I explaining it to?
SCRIBE: Me. Like, what am I looking at?
FRAMER: They’re BARREL DORMERS. So a dormer is like a roof that projects out from an existing roof. And these ones have a cylindrical shaped roof – a rounded roof.
And so what makes this challenging is, aside from creating circles with, you know, rigid saws and square wood… If you take a cylinder and you bisect it along its length, the profile is a square or a rectangle. If you bisect it perpendicular across its width, it’s a circle. But if you take a cylinder and you bisect it on an angle, the resulting shape is an ellipse. And so what makes this interesting is, this is essentially what we’re creating here – is a cylinder that’s bisected on an angle. And so how the pitched roof lands on a rounded dormer is like – you’ve got to think, I’m taking a flat piece of plywood and making a shape out of it that will receive the pitched roof onto the curved dormer. And so I have to make it essentially become an ellipse.
So that’s what makes that interesting… and then just making, you know, I guess like framing-wise, it is just interesting because it’s like, all the in-fill around that is just all very atypical. In residential construction, you do a lot of things over and over and over again that are the same repetitive you know, walls are walls. But this is fairly unique. So yeah.
SCRIBE: And there are workers in that picture. And this picture?
FRAMER: Yeah, there’s 2 guys and they’re running FASCIA, which is the two by six board that’s held at the tails of all the TRUSSES. And that’s where your eavestrough gets fastened to. It’s like a lateral bracing for the roof members as well.
So we fascia all of our roof before putting plywood on them. And then this one’s cool. It has a bell curve, which is what these little hockey sticks are at the end of each roof truss.
A typical roof would come down, just on pitch, but this has a bell curve to it. So if I were to go –
SCRIBE: Did the trusses come like that, or are you doing that?
FRAMER: No, we have to make those. So if I zoom in here, the truss comes down, and has a FLAT BOTTOM CHORD. And we’ve cut this piece that curves up on top of it.
SCRIBE: So you’re figuring that out?
FRAMER: Yeah, usually I figure that out. That’s what’s fun about what I do – is that they [the structural plans] don’t really provide solutions to that. So, one of the hardest things about residential construction is that the things that we’re provided with, to build the houses are never… nothing’s ever perfect.
And so it’s about trying to be adaptive to the circumstances that you’re looking at and creating a home that looks as close to the design as possible. Because it’s never going to be 100%.
So they provided us with a radius for these bell curves. So like to do a radius, anything that’s curved in wood, you stick a nail and you hook your tape and like, let’s say it’s a two foot radius, I would pinch my pencil at the two foot mark. And as my tape curves around, because it’s holding onto the the nail, I trace a two foot radius arc.
And so we did that on one of these rafter tails and it looked nothing like this. It almost looked straight. And so we made a, like a professional decision I guess, that it was like, “okay, we’re going to doctor this a little bit to make it look more like the picture.
And so I’ve got a bunch of tricks, which I can’t really explain without showing you as to how I typically make a bell curve and it just involves scaling out what’s on the picture and then doing something in real life that kind of fits that.
But it’s just, you try your best to create it. You take a couple different tries at it, and then usually stand back and you’re like, yeah, this looks pretty good. And then you go with it.
There’s a multitude of different kinds of bell curves you could do. And so some of them, we do strictly to plan. Some of them are literally just architectural elevation drawing that shows there’s a bell curve present and gives us no information and we just make it up.
This one attempted to give us information that we determined to be not accurate.
SCRIBE: You’re talking roof tails, like those curved pieces that you made. Like, are you figuring out one and then…?
FRAMER: Yeah. And then you sort of maximize how many can go on a board and then cut them out. So it’s like, yeah, the entire thing is like you want things to be symmetrical. So if I jump back earlier to distort a previous discussion, really briefly, that bell curve here, which is on a much further away gable, and this are supposed to match. The overhang from the side of the building here is about a foot bigger on this side of the house than it is here, which is to plan.
And so it created a scenario where they drew a picture that was almost impossible for us to create. And so what I mean by that, is that you can see on these tails here, there’s no bell curve installed yet, and no fascial board run.
And so this is how the tails look. The flat portion of this tail, I believe on these trusses is around like nine inches, and on these ones here was about two. So that’s a seven inch difference, that’s massive. How do you create the same curve with that much difference?
So that’s what I mean by us taking creative liberties and kind of trying to make something that works, make it look more like the picture. And to your question there, doing anything with roof work, like if we do… this is a truss roof where they’re manufactured trusses that come in and we install them. And then we do some in-fill work to kind of help fill in the holes.
We also hand frame roofs occasionally, which is, you know, using nominal lumber, like 2x10s or 2x12s, and then you cut PLUMB CUTS and BIRDS MOUTHS and FASCIA CUTS and all these kinds of things.
And so when we’re doing that, we’re making bell curves. Anything that’s going to be repetitive, my rule of thumb is always, I create a template. So I make a piece, I mock it up until I’m happy with it. Sometimes it takes one try, sometimes it takes 10.
When I’m happy with it, I take a big ol’ fat sharpie marker, write “template” on it so that no one touches it. I hang it on a wall, and my expectation is that when we leave the job, that template is still hanging there.
And the reason that that matters is – if anything happens after construction and we need to go and reinstall another one of those pieces, if I still have the template available to me, there’s no thinking that needs to happen. I’m able to essentially, it’s…. you know, the equivalent of having a saved document on a computer that you could just take and put somewhere.
So we’ve created this template, and then once we’ve figured out that’s what we want to do, at some point I get a young guy to cut, you know… in this case it was 20, sometimes it’s 200. And then at some point someone goes around and installs them all. And, you know, you make decisions as you’re doing that. Sometimes one of them doesn’t look good or it’s not sitting well. You know, we’re humans and we make mistakes.
And so when you’re the assembly line, and you’re making 60 of the same bell curve, it’s inevitable that three or four of them don’t look good. And so that’s what I try to tell my guys who are installing, is “think about what’s happening here. If it doesn’t look good, if it’s not working, if it doesn’t look symmetrical with everything else you’re putting it on, throw it away and put a new one on.”
SCRIBE: Can you go back to the barrel dormers? Is that what you were trying to explain yesterday?
FRAMER: Yeah. So I’ll walk you through really quickly. So this is [zooms in on picture]… I mock it [plywood] up in the house. So I’ve created a 16-12 pitch out of 2×6 rafters. I know that where the girders are, that this is supposed to get installed between, it has a consistent distance between them, so I’ve installed these rafters 79 inches apart because that’s where the girders are. And then I’m provided with all the radiuses here on the plans, for a 48 inch radius for the window, and then there’s like a 10 inch span and an eight inch span of stone with a 6 inch span for fascia. So, you know, doing the math, this becomes a four foot radius on the exterior here. Versus two foot.
And so once I’ve done that, I then create a bunch of templates, which I don’t think I have a picture of, which would be usually made out of a three quarter [inch] plywood, which creates kind of like a structural component.
And so what I’ve done here, what’s the best picture to show this? It’s not a good one either. I zooming on these, you can’t really tell, but the trusses are all pitched, and we have what’s called a box truss, which is a piece that’s going this way.
You can kind of see that piece of wood right there. And so that’s about 18 inches tall, about 3 inches thick because it’s two pieces together. It would have a 2 x 6 TOP CHORD, a 2 x 6 BOTTOM CHORD with a couple DIAGONAL CHORDS in it.
Its entire purpose is to hold these trusses that are going back away from it, and to leave a gap where I can build this [barrel dormer]. So to do this work, I create the template for the front roof. I then hang a piece of three quarter ply.
SCRIBE: With the BOX TRUSS, it’s like leaving space for future attachment. Is that the same as when you’re talking about boxing in or strapping out a wall? Like you’re sort of leaving structure for something future to get tacked on?
FRAMER: No, BOXING IN is when we have HVAC plumbing, electrical, anything like that, that needs to get covered by drywall. We box it in with like 2 x 2 and 2 x 4 framing.
But this [box truss] is like the equivalent of a HEADER, a structural header.
SCRIBE: Like a door?
FRAMER: Yeah, or a more appropriate comparison would be like a stair opening in a floor. So on a floor, you have a bearing point and a bearing point and joists stretched between them.
But if you need to create a hole in the middle, you need to put a beam on either side of that opening. And then header it off with new beams, and have new joists hung off those beams so that they’re suspended there.
So that’s essentially what they’ve done here – is that this truss and this truss go from this wall to the wall at the back, but they needed to leave a gap here. Where do these three get hung? They need a place to go, because they’re not stretching all the way to this front wall. So they provide us with a box truss, which we install so that it follows the pitch of the roof.
It doesn’t protrude out of the roof, and it receives the bottom chord of these And these trusses, as you can tell here, have a flat bottom chord – they recess up into the ceiling about five foot six.
And so what that’s doing is it’s creating a hole in the ceiling framing so that later on we can frame an arched barrel ceiling that goes back through. And so these are all, you know, this is what I was saying earlier – a truss roof is really good because it’s very fast for install. But then there’s a lot of in-fill work because they can’t do that in a shop. So they just make accommodations for it.
So what I’ve done here is, I’ve hung – I’ve nailed a three quarter sheet of plywood onto these box trusses and then put the three quarter template of the arch on it, which creates an inch and a half material, which is the same as any nominal lumber I use typically for structural framing.
So that allows me then to put… I don’t think I have any pictures of the rafters done before I put sheets on it, which maybe I can try to takes some tomorrow… You can see a couple of them in there. I’ll take a picture of that tomorrow, maybe when I’m doing the third one. with just rafters going back….
So then once those rafters are following the top of this curved arch, as well as the template that I have hung behind it. And so it’s like a 2 x 6 here and then every eight inches, there’s a 2 x 6 that slowly create that pattern.
And then we take half inch plywood and we KERF it, which means you score the bottom of it with about half the depth of the material, and that allows it to bend. And then with a lot of cursing and sweat, you manage to bend this successfully around, and it looks fairly round.
And then, yeah, your question which got me on this whole train here was in regards to this picture, what this piece is. And so, imagine a rectangular piece of three quarter inch plywood that I’ve mocked out an ellipse on. And then cut that out, and then scored the underside and bent that over a barrel roof.
And so that ellipse in 2 dimensions is here, and then we bend it into 3 dimensions. And that’s the math that I was asking AI [Gemini] to help me with. Not because I’m scared of elliptical math, but you know, when it’s plus one degree weather on a Wednesday morning, it’s a lot easier to ask your computer to do that for you, than try to figure it out by yourself. Especially when the guys are hollering questions at me about other stuff.
So that helped me lay that out. And now what’s important about this piece is that gives a solid edge for all of the roof sheeting that lands to have a solid edge. So there’s no buckling in the plywood. There’s going to be a FLASHING JOINT that’s put in there with shingles all over it for waterproofing. And so just trying to do my best to provide what’s necessary there for structure.
SCRIBE: Thank you. That’s cool.
<|[This is part of a living archive of niche framing expertise from an elite tier of late-career framing carpenters who are building custom luxury roofing systems in south central Ontario. They are sculptors of wood, and SPF is their clay. They do complex mathematics every single day, in full exposure to the worst the weather can throw at them. They work from great heights, knowing how to a keep sound balance and a sense of humor.]|>
