I used this tape for sealing.
Sliding glass door leaking from top.
Sometimes water intrusion is severe staining carpets and causing dryrot at the subfloor baseboards and sometimes even the wall.
Try to follow where the water will go when it hits siding when it hits door when it hits door frame when it accumulates on the threshold or patio porch deck and see if any of the flow paths by gravity or by wicking along relatively tight interfaces allows entry into the house.
Test the door for the location of the leak.
If you cannot re create the leak problem inspect the interior of the door for stains or rust.
Spray the door and look for the leak location.
A sliding glass door is no better than the frame into which it is placed.
Once you ve exposed the top sides and bottom of the door you can assess what needs to be.
In this video i show you how i repaired a leak by replacing an incorrect capping job.
There are 2 drain plugs in the bottom of a universal sliding glass door one on in each corner.
Be sure to tape thin sheets of plywood over the glass to protect the door from flying pieces of concrete.
Check to see which door moves and which one is the stationary.
To slide the heavy doors along the metal frames the doors use metal or plastic rollers.
Water leakage is a common problem with sliding door thresholds.
Since sliding glass doors and sliding impact windows are heavy they move along metal tracks fitted to the bottom and top of their frame.
If a frame is crooked water can leak into the gaps between door and frame.
If you have a problem with water leaking it will usually be on the bottom track threshold of the non stationary door.
Aim a garden water hose with a sprayer set on mist or low at the outside of the sliding door.
The plugs are usually in the top but if the universal door ge.