When the operating (moving) sliding patio door closes and
locks, the other end should interlock with the stationary door (fixed panel) to
seal out wind and drafts. There can be several reasons why this interlock may
not perform as designed... 1. The weather seal has worn and needs to be
replaced. 2. One of the doors, usually the operating door, is warped. 3.
The stationary door (fixed panel) has moved away from the jamb slightly and does
not allow for a good seal at the other side where the doors interlock. 4.
The width opening for the sliding door system may have been sized slightly
too small during installation, usually by a 1/4" - 1/2", which prevents the operating door from
having enough room to close far enough to interlock with the stationary (fixed
panel). The solutions are as follows: For #1, The operating door needs to
be temporarily removed so that the weather seal can be replaced. For #2, The same
as above, but oversized weather seal material needs to be used. For #3, The fixed panel needs to be re-set in the jamb and secured. For #4, The fixed
panel needs to be removed and the jamb side planed (shaved)down the necessary amount for the doors to seal.