Tying new roof to end of old roof. . .input?

I’ve got a deck that I’m wanting to screen in/roof over. My question is this – the roof of the house that the deck extends off of slopes down towards the deck – obviously to a gutter. Can I 1) pull off that gutter, 2) tie the NEW roof (going over the deck) to the fascia or rafter ends of the existing roof, and 3) let the water that runs off the “house” roof run right on off the end of the roof onto the “deck” roof and, henceforth, off the end of the roof into gutters at the end of the deck? The slope of the house roof is 6 in 12…I want the slope of the deck roof to be considerably less – metal roof like 1 in 12 or something. Can I do this? Would that put too much water onto the deck roof??

Any input??

Thanks in advance. . .


Pictures would help tremendously.

Anything is possible in T.N.,lol


The volume of water is not the issue. You need to tie the rafters into the existing roof so that the weight is supported.

Connecting to the facsia will not work.

use a flat roof product on a 1 in 12 slope.
no metal.


I’m still trying to upload pictures. . .still working on it, sorry.

So if I essentially bolted them/secured them to the existing rafters, good enough? I.e., pull the gutter/fascia off, and then tie them through and through to the ends of the rafters? Make sense?

Why no metal? Expand on your advice, please??

Thanks so much in advance. . .


expanding on my advise.
never thought of it like that.
expanding indeed i am.

mr murf,
you just need to have enough slope when usin
it really needs a 2/12/p or more to shed water
well enough.
i a hard rain the water will simply get deeper than the seams and pass through.
so imo you need a flat roof product on you 1/12/p


I don’t know what I’m doing wrong to post these pictures – still trying it, sorry. At any rate, I can see where that would be a concern. Are roofing products “rated” for certain pitches? That is, how does one decide what pitch to build, based on the desired product. I should say that I’m in Tennessee, so snow is (usually) not a big problem.

If I can ever get this picture to attach and not be bigger than a billboard, it will help. I should say this – my initial thought WAS to run the “new” roof off the “old” roof; that is, attach a “ledger” or mounting board to the “old” roof and use this as the base/support for the “new” roof. Main problem with that was that, possibly, by the time you run off the roof, cross the deck, and attach to the walls at the end of the deck, the span is going to be rather large. The deck itself is 16 feet from the house to the edge, so the span would be considerable. Eh, don’t want to sound cheap, but I was guessing it would be cheaper to just run it off the end of the existing rafters.

Flat roof product – rubber? Easy/hard to install/do?

Thanks a lot in advance. I’ll try and work on these pictures.


Metal requires the seams to be sealed on low pitches, but …I can’t really comment on what I can’t see.

I can picture the transition being a problem , I just tore an alluminum roof off on a 1 1/2 pitch,no rafters ,couldn’t walk on it ,and rotted the facia at the transition.

I tore off the facia ,attached a 2 by 6 to the rafter ends in place of the facia, metal hangers on 2’ centers, and 2 by 6 rafters, osb decking and a modified roof which went under the other roof.Now it dosen’t leak at the transition and he can walk on it to clean it off.

Modified does make for a better transition IMHO.

Alright, finally, I think I got the image to load up and paste. Anyway, here’s the image. The fascia board there is about 93 inches off the floor of the deck. The deck is 16 feet left to right to the railing (out of the picture). My other option was to extend it from the existing roof – place a ledger up on the existing roof and run rafters down at a given pitch to the wall (again, would be at right out of the picture). The problem remains that this would be a long span, and how would I support it. Posts and beam(s)? In the middle of the deck?

Notice also the two slopes coming together near the center of the picture (a valley??). A whole nother problem there. I have no idea how to visualize what to do there. Any advance comments on that would be appreciated.http://www.roofing.com/images/topics/6821/img_1220409537.jpg

Here’s another image – looking straight at the deck and existing roof(s) from the yard. The “valley” junction of the roof(s) at the right creates the other major brain teaser for me. How to negotiate this with the “new” roof that would cover the deck?? Hard to see but you can infer from the gutter(s) at right – that roof slopes down at a 90 degree angle, obviously, compared to the primary roof you’re looking at in the middle of the picture.

Is this a D.I.Y. project?

My thought exactly!

DIY, yes, I would like it to be. I don’t happen to have the money to throw around to hire it done; that, and I like doing stuff like this. Seem too complicated to be DIY?

It is if you cannot envision what it will look like before it is built.
There are many problems that will present themselves as you go.
#1) If you take off fascia and set rafters on wall,the wall is offset by the door.
#2) If you start roof up on main roof,you would need to use a T.J.I. engineered joist to span that far.
#3) that is way more than a 1 man job.
#4) That is a nice house,and if it doesn’t come out just right it will do nothing for property value.
#5) This is a god time to go to a lumber yard with your idea,pics,and ask them to help you plan it out,and what materials you will need. They should help you just to sell you the lumber. Don’t just buy it. Get 2nd opinion!

I forgot that once you build it ,then you have to get into the valley to get the new roofing material under the old shingles. That will be a project in itself

A valid point about going to the lumber yard. . .I get so (stupidly) used to going to some home center instead of a “lumber yard” where they’re used to dealing with stuff like this all day long. Ugh. Well, I’m all ears for any advice, but that being said, we can’t use the deck much the way it is in the summer months – so freaking hot and too many flies/mosquitoes when we’re trying to eat.

IMO I would buy one of those large screened tents that you can put on the deck,and remove in the winter mos…Just a thought. And no chance of property depreciation…

I forgot to say this – about the door and the offset. I’m not sure, and you can’t tell by looking at the photo, but I’m 75% sure that there is a header/beam spanning the space there in front of the door. Hard to tell from the picture, but if I walk out the door about 3 feet and reach straight up, there’s definitely a “lower” overhead clearance there, covered with aluminum trim/flashing. I’m thinking it’s a beam from left to right to hold the roof?

I would have guessed that . Some times they can biuld a knee wall to support the rafters,and just extend rafter tails to match main.