We have a new addition with one metal door with no glass, and French doors with glass.
I have had 3 different people try and fix them but they still leak. It used to leak the length of the floor from the doors. Now it leaks at each corner of the door and the French doors leak at their corners and the middle on our floor. The only thing we haven't done is cut everything out and start over. Before we do that what could be the problem. I have caulked twice since and now it leaks less but leaks all the same. Everything was new.
Best Answer
Usually†, an external door has a weatherboard with a drip-channel and a sealing system. I'd check that this is intact. On a badly fitted door, the door can sag and cause the flexible sealing strips to be torn off.
There's usually also a sealing strip in the frame at sides and top, but this is mostly for draughtproofing.
If water is pooling outside during heavy rain, I'd install better drainage. Normal doors are not an effective flood barrier.
† in the UK. Doors differ elsewhere.