Tying two roofs together


#1

Folks,
Old 1920s garage has a 1940s cottage butted up, gable end to gable end, against the back of it. Both roofs are simple, single ridge, straight run roofs, ridges run in the same line, and the rafter runs are the same length. Just two separate buildings, butted up against each other and until this week covered in one long, huge, monolithic rolled-roofing covering. 20’ wide, 65’ long rolled roofing, ugliest thing you ever saw

Ok, so hopefully you have the picture in mind. The problem is that tearing off this covering revealed that where the garage roof ends and the cottage roof begins there is a drop of 2 inches at the ridge and a varying distance drop all along the rafter run. Filling this gap was fiberboard 2" thick, 2’ long and shaved to a wedge to fill all along the roof line and make a smoother transition.

So, I’m going to shingle both roofs but between them I want to add some architectural feature that’ll solve the problem between the two roofs better and also break up the huge expanse of same-same roof.

I’m thinking about building a parapet, a low-slung monitor roof or low cupola with a low wide base across the entire width of the back of the garage roof. This’ll create a large area to flash against on both sides and break up the expanse.

Sound good? Alternatives? Designs? Some place, any place, to find designs, construction details on parapets, monitor roofs??? Please.
Or do you have experience building these and can help a newbie?

Thanks,
KWL


#2

Gotta have pics for this.

You are talking about some pretty old stuff here.
Is it possible to just stepflash the transition between the 2 roofs?
What else is under there?


#3

Axiom,
I’ll get some pics next sunrise.

The problem is that I don’t think there is enough “step” in every place to get the flashing on well, and I’m afraid the varying heighth all along the line would make it look like hell by the time I got done. While I was standing there scratching my … wondering what to do I wished there were more height to flash against and that’s when I thought a parapet would work but…, not having built one, and someone suggesting a monitor roof, and another a cupola and stepped base, I thought I’d better go ask the experts and maybe even find someone who does these architectural roofing details.
Thanks
KWL


#4

maybe use a cold modified same color as shingles.
use the modified as an expansion joint.

gweedo.


#5

I know cost is always the factor, but why not try to shim with some fur strips, taper system and put decking. The only issue might be the fascia line, but since I can only guess, you’ll have to think if it’ll work. Don’t you love those tear-off suprises.


#6

[quote=“kwlandry”]Folks,
Old 1920s garage has a 1940s cottage butted up, gable end to gable end, against the back of it. Both roofs are simple, single ridge, straight run roofs, ridges run in the same line, and the rafter runs are the same length. Just two separate buildings, butted up against each other and until this week covered in one long, huge, monolithic rolled-roofing covering. 20’ wide, 65’ long rolled roofing, ugliest thing you ever saw

Ok, so hopefully you have the picture in mind. The problem is that tearing off this covering revealed that where the garage roof ends and the cottage roof begins there is a drop of 2 inches at the ridge and a varying distance drop all along the rafter run. Filling this gap was fiberboard 2" thick, 2’ long and shaved to a wedge to fill all along the roof line and make a smoother transition.

So, I’m going to shingle both roofs but between them I want to add some architectural feature that’ll solve the problem between the two roofs better and also break up the huge expanse of same-same roof.

I’m thinking about building a parapet, a low-slung monitor roof or low cupola with a low wide base across the entire width of the back of the garage roof. This’ll create a large area to flash against on both sides and break up the expanse.

Sound good? Alternatives? Designs? Some place, any place, to find designs, construction details on parapets, monitor roofs??? Please.
Or do you have experience building these and can help a newbie?

Thanks,
KWL[/quote]

Photos would definitely help. If what I’ve got pictured in my mind is right, the main advice I can give you is to keep the two roof systems separate.


#7

yeah the parapet sounds good i see that alot on additions when the carpenters dont wanna tie the roof sheathing from new to old in thats what i would do use a 2" x whatever step both sides and cap it man i like this forum


#8

the step will be your base flashing of course and the cap on the 2"x will be your secondary flashing this will allow for movement just like at chimneys and other terminations also make sure the 2"x is nailed to only one of the roofs at the edge or it’ll look terrible