[Lynda]

I attached a tin roof for a porch into the existing shingles of my home, I used flashing and sealed it with roofing cement and it still leaks, I have tried everything I know, it leaks where it connects into the existing shingles, any ideas on what to do next? help?

 

[Ed the Roofer]

You only brought the flashing up under one course of shingles probably.

You need to remove the nails from the next row of shingles and get the flashing higher than the key ways, aka slot lines, for the top edge of the flashings to be covered by shingles.

I made that mistake when I was first starting out too.

Ed

 

[VaViaCo]

Leak

A lot of times when we added sunrooms to homes we'd have this and it was a leak way further up the roof from where we were working. So the water was running on the felt paper under the shingles into the gutter until we came along and added another roof. Then it was under our roof and into the sunroom.
You've got to get under the paper with ice/water shield or at least new felt paper directly on the wood.

 

[My Old House]

Agree with these guys. Make sure your flashing laps under the shingles (bottom row should be doubled to address keyway issue) by at least 6-8". If you have exposed keyways, then measure from that point. Another common source of leaks I've seen is a byproduct of the installation process (for some contractors). With most pitched roofs you will see them nailing 2x4s or similar (through the shingles) as footholds during installation. This is pretty common, but I would never let someone do this on my house. Some contractors are good about sealing the holes at the end of the job, and this is better than not. If the damage is done, a good sealant at each penetration is the only way to fix it.