Creating accurate house roofs

Have been wanting to make some small N an HO scale houses for a friends train set and was wondering if anyone knows of a free or cheep roof maker? The exterior walls are simple enough but when it comes to the roof things get complicated at least for my simple mind.

A simple a frame type roof is easy or even a hip roof but then im trying to put a dormer or any secondary roof and the angles are killing me.

Have looked around the net and the only things I can find are like free home designs but the dont give any angle degrees and obviously the build on a real home is completely different.

I know there are some really neat box maker programs out there but didn’t know if anyone had made some sort of roof designer that made the svg or at least gave the proper angles.

I realize someone is gonna tell me it’s simple geometry but simple doesn’t seem to be in my brain at least currently.

thanks in advance


I don’t have anything to point you to - but my go-to with funky designs/angles is to buy a finished design that works, and then break that apart holding on to the thing I can’t figure out - and build my next design starting for that base. Of course that only works if you can find a design that has all the angles you’re looking for, but it’s a start!


Found a couple free house designers that gives images of the finished roof you simply click on the box you might say the interior walls that you want to cover tell it what the pitch of the roof you want and what type and it generates it really slick. Problem is I can see it yep but getting that 3d design image to something useful has had me pulling my hair (whats left of it) out.

I guess I can just practice and error until I get things right. Wished I had paid better attention decades ago in geometry cause I know it’s a simple math problem.

I’ll figure it out eventually just figured I’d ask if there was some simple generator someone has made like the box generators before I spend a week reading some neighbor kids geometry book hehe.


Possibly @andrewmchaffie or @cynd11 or @timmystreehouse can help? :slight_smile:


Roofs are my nemesis as well! Dormers are the worst and hip joints are not much better, lol! I wish I did know a “simple” way to figure out those angles but I don’t. Really the “right” way to do it is to use the Pythagorean Theorem. Unfortunately, I gave up on algebra long ago - doesn’t sound like you want to go that rout either. :slight_smile:

So what I do is make the main part of the roof at whatever angle I see fit, then cut the sides of the dormer (or hip joint) out of a piece of card-stock with a pair of scissors until it’s as close I can get it - takes some trial and error but for me is quicker than math. Then I just measure each side of the paper and enter those numbers into my design software. And keep in mind the angles don’t always need to be perfect as you can hide any small gaps with shingles and/or other roof debris. Like this…

I cut ALL my models (with the laser) out of card-stock before using more expensive materials - especially roofs. You have to adjust for material thickness but at least that’s a “known” number.

I got the forge a little over a year ago for the sole reason of making models for my train set. I’m no Pro or anything but if ya want to “talk shop” I’d be happy to share some of the things I’ve learned or trade files. Here is part of my layout…


Here is a .svg file of a little Farm House if ya want to play with the roof.

1 87 Scale Farm House


No help with the geometry either, but for shingle detail, I have seen a crafty individual cut them from sandpaper. Just cut it from the paper side, the back. the laser won’t cut through the grit well.

Boy that looks awesome!! Just got the glowforge haven’t made much of anything yet little stuff working on getting better with the software. Before this I had a carvewright worked a lot the same but was a cnc machine but real close to the same concepts easier to make larger cutouts and remove wood but not as precise.

Much appreciate the reply and the svg to play with.


Hehe or poster board I was piddling around last night at the coffee table trying something similar without much success but I think I might if I made the main roof first then use the card stock on that like you said instead of trying to make the entire thing from card stock first.


Wow, looks like @timmystreehouse has totally mastered the roof creation process. I confess that I cheated when I did mine. I have a piece of software called Home Designer Studio (I had it already, didn’t get it for the tiny house). I modeled the house in that software, which has a ton of roof options. Then you can print a 2D plan of the house for the purpose of making a model of the full size one, and that’s how I generated the roof design.


Your assumption that building a tiny roof is different than building a full-scale roof is what’s causing your issues. Both tasks are exactly the same, and yes it’s simple geometry, but it’s even simpler if you disregard the geometry and simply use measurements pulled from a 2D drawing of what you want to build. panel length and width are constants, for angles you take the known lengths of the adjacent legs, ridge, and fascia when constructing a dormer, then simply close the object with a line.


I played with that software today and yes it’s amazing how easy it is to make a complicated roof.


I just got the limited free version and couldn’t figure out how that 3D model was going to get into my design. The building yes easy as pie because it’s all flat surfaces but the roof because of the angles looking like from the front the angles are obviously completely different than looking from the top if that makes sense.

Sad thing is I did construction my whole life either on houses or welder fabrication depending on what decade but this stupid thing is killing me.

The paid version of that program is pretty cheap maybe I’ll check that out.



See I’m having issues I guess because it’s on the computer I guess maybe in the past way past we typically just sized things up no computers then. Although I must admit I never messed with roof trusses.

I’ll get it one way or another I don’t give up might have to lay it to the side for a bit but I’ll get it.


@allen-deckard why don´t you try out this website:

Calculators for Contractors, Builders, Remodelers, Carpenters, Woodworkers + Scale Modelers

Let me know if it helped you. Regards.


Peaked at it a bit tonight on the couch I’ll have to mess with it more tomorrow. Pretty complicated I might have to go with the low tech scissors approach mentioned above. :stuck_out_tongue_winking_eye:

Hi — as mentioned, the real life measurements are a good place to start and the math is then a little clearer to deal with. I start with 2d doodles in my sketch book marked everywhere with measurements, usually the actual measurements of real buildings. My next step is a 3D model with Fusion 360 (which is not cheap but there must be equivalents that are less). In F360, I use a custom parametric unit that is 1/87th (for HO scale) real life measurements. That way my brain can still work in metres (or inches) and the computer does the calculations and modelling in tiny fractions of a mm. I also once used a spreadsheet where a column was a calculated fraction of a reference number—so I was essentially still using the real-world numbers.

Only once I have the building modelled do I then look at converting the surface shapes to cut out panels with interlocking tabs that are specific to the material thickness.

The posted examples above are fantastic—a level of skill I still aspire to.

A couple of notes about F360… they used to have a free for hobbyist licence. I don’t know that they do any more. If they don’t , it is expensive if you are using it for a hobby. And… when I first started using F360 a couple of years a go, I really struggled getting used to it and using it efficiently, even though I have used 3D modelling software for several years. To be fair though, I was not using it as much as I could/should have and now that I am used to F360, I find it quite powerful and I clearly don’t use even a 1/4 of its capabilities.

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They still do :slight_smile: it has limited functionality.


I enjoy geometry puzzles and so I made this SVG generator for a Gabled Dormer in Cuttle. (Cuttle is like a parametric Illustrator webapp that I’m working on.)

gabled dormer gif

You enter the angles for the primary and secondary roof (in degrees) as well as the width and height of the dormer.


You can then export an SVG (File > Export SVG). I did a quick sanity check out of paper and it seems to work. I haven’t tried it with thicker material though.

Maybe this could be a good starting place for your roof designs? I’m happy to make adjustments or add features to this (overhangs?) if you tell me what would be most useful for you.

Also let me know if I’m using any roof terminology incorrectly :blush: I’m going off of what I googled just now…


Seriously @tobyschachman, you rock!

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OMG!! you have no clue what you just did for me your awsome