House roof question

[ScubaLatt]

How long after one buys a new home is the contractor required to warranty the roof?

About a year after we bought our home we had a roof leak. Called contractor and he came out and "fixed it". Discovered about 2 weeks ago the same area again was leaking and upon inspection found about a 3x3 area of rotten roof decking in attic. Water has been leaking into my electrical panel for who knows how long. Also when in attic I could see light coming in from under the flashing.

We have noticed over the last year that our can lights would simply go out every once in a while. We blamed those new fandangled light bulbs but now think it has to do with water in my breaker box.

Just wondering if contractor should be held liable.?