roofs and dormers

HI there, I have been through the various tutorials, and am trying to make a roof that should totally be possible, but I can’t get it. The main roof is 9:12, intersecting roof is 12:12. The little dormers are 9:12 and are higher than the eave, the big one on the front (top here) is actually 14:12 and lines up at the eave. I make various changes (each of which seems quite laborious) and just end up getting very distorted roof lines.

I would also like to have different overhangs on the 2 main roofs so their eaves line up. Is that possible?

I’m hoping the picture I’ve attached helps to visualize…


roof plan.jpg

Hi Dawson,

Thank you for your post.

I’ve uploaded an example roof (which you can downloaded) similar to the image you sent across. I used degrees in my model but the principles will still be the same. If this is the result you were after, below is how I got it. I will be referring to the image I attached throughout it.

I made the white, grey and yellow sections of the roof into one roof. The white and yellow sections were raised higher then the grey section and the yellow section gable side was extended past the fascia (I extended it 100mm but you can use whatever length you want) and then added all the gables and different pitches around the roof using the Edit Roof Pitch Tool.

I then manually edited the yellow section to line it back up so that the fascias of the white and yellow sections lined up by pushing the gable back the distance I extended it. I also manually edited the gutters to suite the new shape. Please note that any manual edits should be done last as if the roof is redrawn any manual edits will be removed.

I then made made the two blue sections as separate roofs and then moved them into their positions. To get the shape of these roofs I made one end a gable and the opposite end I set the angle more than 90 degrees to match the adjoining roof pitch (180-adjoining roof pitch is the best way to do it).

Would you be able to please let me know if this works for you?

The next version of PlusSpec (which will be out very soon) has an overhaul of the Roof Tools which will make doing more advanced roofs a lot quicker and easier to do.

Also, if you have any advance questions on how-to’s we have a online one-on-on training service which I would recommend having a look into. The link below will take you to a page on our website which explains the training in more detail.
Example Roof Plan.jpg
Example Roof.skp (250 KB)

HI Grant, thanks for that. I think I see how that works, mostly. As for the file, it seems I am running SU2015, so was unable to open it. Could you resend it in that format?

For the little dormers: does that cut the eave line of the main roof? The eave would go right through windows if not…

Looking forward to the new roofing tool! When do you expect that to be out?



Hi Dawson,

I’ve reattached the roof example file as a SketchUp 15 model so you’ll now be able to open it.

In the example I drew I didn’t cut the main as I wasn’t sure if they cut or not from the image provided but you are able to get the main roof to cut with the dormers. To cut the dormer roofs raise these sections higher (to the pitching points of the dormer roofs) than the face the main roof is created from (like in the image below), then select the the top faces of the shape (the blue sections in the image) and then select the Hip Roof Tool :roof-tool3: and click submit and the roof will generate. After doing this you will then need to use the Roof Edit Tool :roof-pitch-tool: to create the gable ends where needed and change the roof pitches.

Would you be able to please let me know if this works for you?

We are expecting the next version to be available early next month sometime.
Dormer Roofs Example.png
Example Roof15.skp (251 KB)

HI Grant,

I faked the roof to be ok, but I have tried to make it right separately. I can get most of it but I am having trouble with this last face. I have included the file I am using. Could you have a look and let me know what you think?


24x40 roof.jpg
My Example Roof plan 15.skp (197 KB)

Hi Dawson,

I checked the file you sent across and what I would recommend to do to line up the eaves is to either:

a) Create the roof from the fascia line with a ‘0’ overhang/eave measurement. To do this offset the face the distance of overhang then create the roof (with a ‘0’ overhang) then once the roof has been generated edit the roof pitches to suit and move the roof down to meet the walls below. This way all eaves will line up no matter the pitch of the roof.

b) Create the “wing” of the roof as a separate roof then edit the roof pitches (over-pitch the side that joins onto the adjoining roof) and move the roof into the correct position.

I would also recommend extending the face(s) you create the dormer roofs from towards where they meet the adjoining roof.

Would you be able to please let me know if either of these work for you?

Hi Grant,

I could see how that would work in theory. In this instance, while trying to cut a dormer roof as well, it seems it couldn’t make out the geometry. The gable wouldn’t project an overhang, and the dormer side sees it as many faces rather than one. Is there an order to the pitch editing that makes it work?

And as to where to locate the dormer pitching points: should it be set to where the roof surfaces end up lining up? or from the pitching points? I think I’ve tried both, and with the main part being generated as 9/12 and then converting to 12/12 it gets extra tricky to know where to start. Doing it as separate roofs might make that more straight forward…

hard to know how much work to put into this if there is a new tool coming…


same eave lines.jpg

Hi Dawson,

From the image you provided it appears as though the face used to generate the dormer roof was offset further back than the fascia line of the main//other roof. This could have an affect on the roof and give you the result that you got. If you line the fascia of the dormer up with the rest of the roof it should fix the issue. Also, sometimes there is a better order to edit the roof pitches but most of the time it doesn’t matter.

When it comes to lining up the dormer roof if you’ve drawn the roof from the fascia line with a ‘0’ overhang then I would probably set it to where the roof surface line up. The link below is to one of our roof tutorials which should help answer the questions you had in more detail. If you are having trouble matching the roofs up then I would recommend creating them as separate roofs.