I rebuilt and roofed my patio cover. Was just a trellis before, now a full asphalt tile roof. Now that the rain came, it leaks around all the edges where it meets the existing clay tiles. The new OSB and composite tiles but to the fascia just under the existing tile overhang. The existing tiles overhang the roof edge by about an inch.
I have tried to fill this gap in with Henry's polyurethane flashing seal, similar to SeikaFlex. No luck.
I believe my mistake is that I need some sort of flashing from under the clay tile and on top of the asphalt tile? how do I get it under the existing clay tiles, and do I completely seal it to the asphalt tiles?

 

Sorry, a picture(s) is needed to understand what your dealing with!

 

Some pics of where the two roofs meet. not sure why the pictures turned 90 degrees but you can see the details

 

Well that is not the sort of thing you can attach and not expect to leak unless you remove the first 2 rows of tiles. That flashing needs to be like 12" wide to go under the existing roof.

Secondly your shingled roof is too flat for shingles so it will leak, no matter what. Asphalt shingles should not be used if the pitch is less than 2:12. Meaning 2 feet of drop over a 12 ft span.

No wonder it leaks!

 

Yea, that has the potential to be a long term issue.

Can't really tell from the picture but it looks awful flat, an alternative material would have been better.

As XS noted flashing way under the roof tile, under the underlayment, as well as drip edge around the perimeter to cover up the ugly edge of OSB and keep water off!

 

Yes you will need a flashing.
Hard to tell if it would even be possible to get a flashing under the first course now that the shingles are done.
Perhaps installing it under the second course of tiles and then out onto the shingles would work but it will not be pretty.

As Marq1 said you also need a drip edge,
It is hard to tell but the drip edger under the tiles looks like it has a problem in that it does not extend down over the facia allowing water to get in.

 

Left as is I expect you will eventually have roof problems on the main section. Water and/or ice will work back up under the house tiles and rot the roof decking and create even more issues. Remove this porch roof and either hire a professional or educate yourself on proper construction techniques. Not meaning to be harsh, only to get you to realize there is no good way to make this work long term.

 

Bummer, Thanks to all
Any suggestions on a different type of roofing material
The pitch is 1/4" in to a 12"

 

The only suitable roof for that pitch is going to be epdm.

That's a suitable pitch for a driveway... not a roof!