topic Re: Joining Roofs With Opposite Slopes in Revit Architecture Forum

Joining Roofs With Opposite Slopes

dhall108 — Fri, 24 Apr 2026 19:02:40 GMT

I'm trying to join two roofs together that have opposite slopes. One has a positive slope and one is a "butterfly" style roof with a negative slope. The roof join tool refuses to join them together because of their difference in slope. Image 2 shows what I want them to look like, which I did by just pushing the butterfly roof into the other one, which is obviously not a valid solution because it leaves excess geometry in the plan space. I created both roof segments as one roof, which worked, but it means I lose individual controls for vertical offset, roof type, and rafter cut style for each of the roofs, and can only change these parameters for the combined roof as a whole, which doesn't fit my design either. How do I achieve this?

Re: Joining Roofs With Opposite Slopes

lucdoucet_msdl — Fri, 24 Apr 2026 22:05:20 GMT

I am not able to reproduce your problem with the attach roof tool and no changes to the relative slopes of the positive or negative slopes seam to prevent the joining. See green joined to blue-grey.

An import limitation to understand is that the join roof tool will only remove the projecting part of the second roof that is intersecting with the main roof. See the extended part in the orange example above.

Are you sure you are using the "Join Roofs" tool and not just using the "Join" tool between two roofs?

Can you explain what differences in slope the two roofs have other than one is negative and the other positive?

Is the butterfly roof also sloped in the direction of the roof valley? If so, I don't think the "Join Roofs" tool allows the joining to a roof edge with a slope value. Edit the butterfly roof and uncheck the "Defines Roof Slope" for the edge facing the main roof and try the "Join Roofs" tool again.

Hope this helps,

-luc

Re: Joining Roofs With Opposite Slopes

dhall108 — Fri, 24 Apr 2026 23:58:22 GMT

Thanks for the detailed reply. I was using the roof join tool, and after opening a new project and setting up the same roofs and joining them together it was successful. It then occured to me that the issue might be the fact that in my original project I'm trying to join two different roof types together. It seems that Revit only allows similar roof types to be joined with each other. After changing the roof types to match each other, it does indeed join correctly. Is there any way to join roofs of different types together using the join tool? I attempted to change the type of one roof after joining them, but they immediately unjoined.

Re: Joining Roofs With Opposite Slopes

lucdoucet_msdl — Sat, 25 Apr 2026 19:50:43 GMT

The roof join tool has a requirement that the edge to be connected must not define a slope. So in that sense, if you have an existing hipped roof you want to attach to a new gabled roof, you will have to edit the hipped roof edge and turn off the slope then join to the gable. Hope this helps,

-luc

If you are referring to other Revit roof creation types such , by footprint, by extrusion or by face, I don’t know.

Re: Joining Roofs With Opposite Slopes

rosie_lucas1 — Tue, 28 Apr 2026 19:05:54 GMT

Hey there @dhall108 just wanted to check in—did the responses from @lucdoucet_msdl help clear things up for you?

If they did, it’d be awesome if you could click the "Accept Solution" button. It makes it easier for others to find helpful answers too.

If you’re still stuck or need more help just drop an update here, and the community will be happy to jump in with more ideas or tips.

Looking forward to hearing from you,

Rosie | Community Manager