Dear Bob,

I would be grateful for your advice and suggestions on a problem with a set of sliding patio doors. 

These four doors are made of kwila (a Fijian hardwood) and are about eight years old.  They measure 2400mm in height by 720mm in width, but are double glazed, the members surrounding the glass being 110mm wide.  The four doors slide in an overlapping manner, so that any combination of 1-4 doors may be opened.

The problem is, the two central doors (and to a lesser degree the outer pair) have bowed significantly, so that at the centre of the doors there is now a maximum gap of over 10mm between the overlapping edges of the inner and outer doors.  This far exceed the seals that were installed in the overlapping sections when they were manufactured, meaning that there is now a mighty inflow of cold air!

I am pondering on what might be done to address this problem, and I am reluctant to try any sort of adhesive draft-stopper insert, since the gap to be sealed is itself tapering.  I wonder whether the bowing in the doors can be corrected if they were layed flat, and assuming that was feasible, I have thought about the possiblility of routing a groove in the edge of the door and somehow installing a rigid metal insert, to oppose the tendency to bow when they are upright.  However, I have no idea whether such an idea is practicable.

I would greatly appreciate your thoughts on this conundrum.

Kind regards,

Peter Charlesworth (New Zealand)