Why can't I make this roof??

[ganeagla1]

Someone else designed this roof, but I feel like it should work, but I can't make it work on Revit. There is a lower roof at a low slope and then the main higher slope roof. 

I tried making it as one roof but Revit says it "can't make roof". So I made it as two separate roofs.. however the intersection of the two roofs was awkward. Then I joined the roofs and edited the main roof so the intersection was at the correct height, but as you can see in the elevation it still doesn't look right. It looks like the main roof just cuts off before the low roof. Can someone pinpoint what is going wrong here?

[barthbradley]

Can you just post the file please, @ganeagla1?   

...aren't you missing the hip slope at the bottom of screenshot? 

...if I'm reading your pitches correct and it's one continuous plate height, this is what I get.  Not very pretty.

[ganeagla1]

You are right about the lowest hip slope but that was just one that I redid for the purposes of the screenshot. I've tried making it more than once and so it's not that easy i'm afraid.

[ganeagla1]

Yes that appears to be about it, but the slope on the low roof is actually 0.5" per foot. The plate height needs to be continuous.

And yes it may not work as a roof. As I say, I didn't design it and they didn't use Revit. So any suggestions on what the roof should be?

[barthbradley]

Yes, I have some suggestions.

1. Two Roofs joined together.

2. Make low pitch roof (over patio area) a shed roof -- not a hip roof.  It will never frame that way.  

3. You might want to drop your plate height slightly at the shed roof to make a better transition between two roofs. 

[Corsten.Au]

Roof Profile Explained

View

[barthbradley]

...Another suggestion: change the slope on one side of the wraparound shed roof. Change it enough so that the ridges of both roofs line up together at corner.  

[ToanDN]

Is the original created in Revit?

[ganeagla1]

No. It was designed by someone else and not in Revit. If it had been in Revit they would have seen the problem.

[ToanDN]

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@ganeagla1 wrote:

No. It was designed by someone else and not in Revit. If it had been in Revit they would have seen the problem.

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Then if the eave elevations are the same between the main roof and the porch roof then their calculations where the roof planes intersect were all wrong.  Do you have some elevations from the original roof?

[ganeagla1]

I wouldn't be surprised if nobody did any calculations. It was an SD set and I think they just drew it how they wanted it to work. 

Those are the elevations I was sent in CAD

[ToanDN]

Here is my attempt.

[ganeagla1]

Yes after talking to the builder that's what we want to do. How did you calc out that slope? I tried to measure just the bottom side length to main roof ridge point but that didn't work.

[ToanDN]

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@ganeagla1 wrote:

Yes after talking to the builder that's what we want to do. How did you calc out that slope? I tried to measure just the bottom side length to main roof ridge point but that didn't work.

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I din't calculate.  It is a flat roof based on the footprint matching your image and I edited its sub-elements to add slopes.  The slopes are given based on where the planes intersect.

[ganeagla1]

Can you explain further? What do you mean by editing its sub elements?

Attached is one I did after some calculations and tweaking of slopes. It's not 100 % perfect and still looks a little weird in Section but I think it's good enough to call it done. But I'd really like to hear your method as its sounds more like what I need.

[ToanDN · Accepted solution]

You can modify sub-elements for any flat roofs.  The nice thing is that I can drag a point or a line up and down and it will snap to the plane of the other roof so that the two roof planes will intersect perfectly without any calculations.

You porch roof slopes are small enough to be considered a flat roof so this is a good tool for it.

[Anonymous]

Curious if this house was ever built, and if so do you have the address?  I have a hip roof house that I'm trying to design a similar pitch break wraparound porch for and can't decide if it just looks too goofy. 

[barthbradley]

Are you pinging me this question?  

But - if it can be modeled in Revit, it would stand to reason that it can be built in the real world.   Whether or not it's a smart design is another question.    

[ganeagla1]

Yes it was built, after I left the company. I'll ping you with images.