Some sliding patio door systems have experienced the problem of rain water seeping behind the exterior cladding at the bottom of the glass. To prevent such problems, we recommend running a bead of clear silicone caulk along the horizontal seam where the bottom of the glass meets the cladding.
If the water has saturated the wood beneath for some time, the wood will swell and the cladding will bulge out. This can cause the operating door to scrape the cladding at this point.
To remedy this situation, it is recommended that the edge of the door be trimmed with an angle grinder (enough to clear the bulge) at the level where the scraping occurs.
But, after providing enough clearance to eliminate the scraping, you will find that you now have a slight air gap when the door is closed and interlocked with the bulging panel.
What we need to do is close the air gap with something flexible that will smoothly cross the bulge as the door opens and closes.
We recommend cutting a short piece from a length of door sweep that is designed with stiff nylon bristles. Close the door completely and screw the “short sweep” to the edge with the bristles fully touching the stationary panel
This “bulging” situation has been observed more frequently on some models of Pella doors.