I'm sure that this has been asked many times before already, however I've got a substantial leak in the flat roof over my carport..

After doing some research, I'm pretty sure that my roof is either Roll Asphalt or it may be what I have heard referred to as Built-Up Roofing because from what I have read, these are 2 of the oldest roofing methods out there and this house was built sometime in the 1950's and I'm figuring that it was one of these two methods.

The leak is rotting the wood underneath the roof so I know that I need to patch it somehow to stop the water..

I don't know exactly how to patch it and what to patch it with though..

Plus, there is more than 1 leak...however, I can tell that the absolute worst of the two leaks occurs underneath a "blister" or a "bubble" (where patching has most likely occurred previously)..

Does anyone know what I can use to patch my flat roof with and what other supplies that I will need as far as cement, coating, etc., etc. goes?

Thanks.