# Addition and Roof Replacement



## lebeld (Jan 2, 2009)

Hi:

I'm new to this chat room so please bear with me.

I've attached a picture of my house with a thirty year old addition to house a dining room. I plan to move the side wall out to the edge of the roof line (approx. 5 feet) to make the dining room larger, and then put a three-season room off the back by extending the shed roof (obviously at the same pitch). I will need to set down the three-season room floor level by 7" to accomplish this.

The existing shed roof has a roll roof system, about two years old. I thought about simply extending the roll roof and lifting the lower edge of the existing to roof to lap over the top of the new.

I don't have any leaking of the existing roof, but I'm concerned about the possibility of the new seam leaking and about ice-daming, particularily with the unheated three-season room at the low level of the roof.

The roof pitch is about 1.5:12 and is flashed in under the 3-tab shingle of the steeper pitch roof. 

Would I be wise to redo the entire shed roof instead of trying to splice in the new? Would a membrane roof be a better solution for this project? Is there a reasonably priced product for a residential application such as this?

Thanks for any suggestions.

HVAC Eng


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## butlersprints (Nov 28, 2008)

lebeld said:


> Hi:
> 
> I'm new to this chat room so please bear with me.
> 
> ...


So what you are going to do is enclose what appears to be a covered porch now, then add a 3 season room to that? do you have Ice/water shield on existing roof? I would keep the 2 seperate, but use metal flashing & ice & water shield on both surfaces. The down fall to low pitch roofs ,are even roll roofing doesn't last many years.


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## lebeld (Jan 2, 2009)

I think you understand my situation properly, and yes, there is ice and water shield beneath the existing roll roofing. 

What I think you are suggesting is to install metal flashing beneath the lower edge of the existing roll roofing and flash over the new roll roofing on the lower roof.

I agree that roll roofing has a short life, that is why I wonder if I should strip the existing roof and do the new and old with a membrane roof, or another type?

David


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## butlersprints (Nov 28, 2008)

lebeld said:


> I think you understand my situation properly, and yes, there is ice and water shield beneath the existing roll roofing.
> 
> What I think you are suggesting is to install metal flashing beneath the lower edge of the existing roll roofing and flash over the new roll roofing on the lower roof.
> 
> ...


Well the tricky thing is to flash properly from one to the other, you need to get metal UNDER the existing ice/water shield. Very difficult to lift already stuck ice guard. If you don't do it that way you will never get results you need. any other roofers have any imput? your metal flashing will be in the shape of a "Z". Under top layer of ice guard, down face board, out over lower level shingles, tar & nail down. with low pitch you will always have threat of build up. I would personally evaluate your needs to see if you want to have the burdan. perhaps contiue building in the direction you are extending would give you better results. Just a thought .:whistling2:


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## Slyfox (Jun 13, 2008)

Being that the existing roof is newer and problem free you could use the same materials on the new section and so long as you take the new materials under the existing with out damaging the existing you'll be ok.

Should you decide to use a better system that will give you a longer life span than yes you should remove the existing and do the entire roof.

There are several systems that will work well on that type of roof.

Check out ABC Supply .


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