I.have a lot of water on my patio and it drains back to the footings of my bungalow. On a bad day the cavity fills up to the d p c . So I need a drain from the back of the bungalow to the side to meet up with the gutter down pipe to a soak away. This drain has to go under garage floor. Please help

What kind of help do you need, as the proper way to go about this is interviewing at least 3 contractors, and weighing the costs of the work you want done. Get 3 estimates in writing, from 3 GOOD REPUTABLE, LICENSED, AND BONDED contractors.

Sounds like maybe you could install a sump pump pit at the low spot and pump the water away. The only way to put a 4" pipe under your garage is to jack hammer out a strip in the floor, costly