My new patio door leaks. It has been sealed with silicone but it still leaks underneath. We put new laminate floors in and some of it has been ruined by water damage that we thought had been fixed. The contractor never put a sealer under the door when he installed it. Needless to say he isn't our contractor anymore but the damage has already been done.
Diane ~ Cedartown, Georgia
There are lots of factors at play here. Without actually seeing your exact situation I can only give some general advice. The type of door ie, sliding, french, single, in-swing, out-swing, type of threshold can play a big role in what solutions will work. Exterior patio doors, especially ones that get direct weather exposure really need to be sealed tight, as you have witnessed.
The best way to seal around the base of the door is to install the door in a door pan. This has to happen at the time of installation. However if this new door is not installed behind stucco, brick, or anything that is real hard to remove, then pulling the door out, and installing a door pan and sealing it right, might just be the best course of action. Once a door leaks, especially if it leaks from under the threshold, the application of more sealant is generally only going to offer a short term fix. It won't take a much ruined flooring to justify the cost of reinstalling that door.