Leaky flat deck roof house is asphalt but need rubber
 

Just curious, I have a leaky deck roof that leaks no matter what it seems

I am breaking down and putting on a single piece rubber roof on only the deck.

I am still at the decision point whether I want to rip the rubberized shingles off and the put on plywood to cover the irregularities for the rubber roof or just leave them on and put plywood over the mess.

However my main roof is endura and asphalt

Rubber cannot contact oil or asphalt, so what barrier do I use to lap the rubber into the crossover to the main roof?

Both sides of the xover have tar so I am left with tin foiling the whole leading edge (both top and bottom of the rubber) which isn't recommended either.

What do I do in this circumstance?
There must be a barrier for the rubber roof besides 5/8" plywood?
Seems like someone would make a coating for this issue.

Ah well

I get the leaky part, but is it a roof over a deck or a deck over a roof?

What is the pitch? What is the framing?

Cross-sectional pic?

2"x8" timbers 3/4" plywood a foot drop over a 15' run

The attached fully enclosed deck has a roof that leaks

We have a wide (4') section of flashing going from the roof of the house to the roof of the deck.

The flashing is covered by asphalt shingles, deck seems to leak near the end of the run where it has settled down

Got it. What's the other dimension of the flashing? Wide or long?

With that low a pitch, a membrane or hot-mopped asphalt is required. I'd tear off the old shingles and check that the rafters haven't sagged so one or another is lower in the middle than at the walls. One rafter between two others can form a bowl.

My situation is that I own my home and rent the space with car port/shed. Same deal — asphalt shingles on a 1/2"/ft pitch. There is 4ft between the two. I got a 4x10ft piece of double-wall greenhouse glazing to bridge the gap, with a 3"/ft pitch. I've got a Shopsmith and some shelving there now.

Flashing is the 20' width of the deck with a 4' run
Flashing also goes over the edges

I have a edpm rubber roof sized to fit in my trailer issue now is how to deal with the overlap that goes up into the main roof

It will touch asphalt materials, i need to figure out how to make a barrier so the edpm rubber can touch the ondura and tar paper in the main roof

I wasn't going to comment without a cross-section to work with, but...

A pitched main roof 4ft from a flat carport roof? Are the eaves level or is one higher or lower? What supports the 'flashing'?

Generally, to separate the materials you'd use actual flashing to underlap the main roof and overlap the addition.

Is there any gutter or does the main roof discharge directly onto the carport?

Everything is one continuous roof with a pitch change, main roof flows onto the deck roof

I still don't get the idea of a 4 foot wide 'flashing'.

From the main roof to the flat roof we have a hunk of sheet metal that goes over the transition.

The roof doesn't leak in that location, it leaks downstream near the edge of the roof

I'm starting to think you're trolling me. I understand:

• pitched main roof
• flat deck roof
• metal transition

What I've asked repeatedly is

• which eave is higher the main roof or the flat roof
• which way does the 'flashing' drain, in the 4ft or 20ft direction
• what (again) supports the 'flashing'

Also, why not obviate the material compatibility issue by putting in a 4x20ft skylight?

And a gutter, if the main roof washes over the flat roof it will degrade the life of the flat roof. Good thing it's membrane. Make sure it's flat or you'll have standing water in puddles.