Rubber roof question

[Tyger52]

I have a leak in my patio room that has an almost flat roof. The roof is currently covered with three or four strips of thin material that looks like composite. I am seriously considering a rubber "EPDM" roof and for the 20' X 15' area, the price of the materials is about $400. The sales person said I could just glue it down to the flat roof. I was instructed to attach it to the existing composite roof by taking the nails off for 2 feet from the bottom and slide it under the shingles. Any experience with doing this? Pointers?

[shinstr]

You are describing both the shingle and the low slope areas as "composite".
This would lead me to ass-u-me, that the patio area is a granular surfaced asphalt material, or #90 rolled roofing.

With this in mind, you cannot simply overlay the #90 with the EPDM; as EPDM and asphalt are incompatable materials. The adhesive will liquify the asphalt and you will end up with a black gooey mess. As well as; any exposed asphalt mastics will blister the EPDM membrane. Usually there ia a seperation layer of some type. (typically a 1/2 inch insulation board fastened to the deck).

The low slope material should extend at a minimun up under 3 full courses of shingles. Remove nails and shingles 3 courses, run the material up as far under course #4 as you can, then re-install the lower 3 courses keeping the nails high on the final (doubled - joints staggered), or lowest course.

Good Luck!

[Tyger52]

How do I remove the asphalt mastic or should I put something over it? I am curious why I need to go so high up on the sloped roof, 3 courses sounds high. The EPDM sales guy told me that I only had to go up 2 feet, but I don't know why I have to go up even that high. I want to get the city inspector involved too, any tips on this?

[shinstr]

Shingles are not water-proof, meerly water-resistant, they are designed to shed water, that's how they get away with having open joints between each one. It relies on the upper half of the shingle below it to keep water out.

Each course of shingles overlaps the other by approx. 1/2. Therefore you are not fully covered until you are into your third course.

the exposure (part you see) on composite shingles is anywhere from 5" to 6" depending on brand, so at the recommended two feet ..you are into the fourth course.

clear as mud?!

If you pull a permit for the job, the inspector should be required to make at least one trip to inspect the work.

[Tyger52]

Thanks for all the information on shingles. What I forgot to say earlier was that there is a drop from where the sloped roof with shingles ends to the flat roof. That drop is several inches. There are two sides of the flat roof that are about an inch under the end of the sloped roof. The two sides of the flat roof join the wall and as I hope I made clear, above that join the sloped roof overlaps by about an inch. Does this make any difference? Any tips on removing or covering up the asphalt mastic?