My uPVC front door has not been catching on the lock as easily as usual for the last few days, though by lifting the handle, it will secure OK.
I looked a little closer, wondering which, if any, of the sundry hinge adjustments might improve matters, and discovered that the catch engagement was less than I had expected.
With a hall temperature currently about 18 C, and external ambient below freezing, is it in any way feasible that it is actually thermal contraction that is making the door small in its frame?
I don't want to make adjustments that will have to be revisited once it warms up a little.
Looking at the range of expansion coefficients quoted for PVC (UPVC not found) The contraction of an 800mm door would be about 0.05mm per degree C so summer to winter variation of 40 degrees could make about 2mm difference. So if you adjust anything now, allow for 2mm of expansion and you should not have a problem mid summer.
Normal cause is the door has sagged from a rectangle into a parallelagram, and this happens because the panels were not correctly heeled and toed with packers to prevent this happening.
With the door pushed closed, look at the diagonal join lines between the sides and top/bottom and see how they line up with the same joins on the frame. It should be obvious if the door is drooping.
To fix, take the beading off the panels (panels may fall out if they are not fixed in with window tape). Wedge something under the open corner of the door to lift it and push it back into shape. Refit the panels, with tight fitting packers at the hinge side bottom and catch side top corners, so the panels are preventing the door drooping. Also note you must always have packers under the glazing units to ensure they are lifted clear of the water drain channels in the frame, or the units might end up sitting in a puddle of water which will wreck the seals and cause misting eventually. Pack other corners to prevent movement of the panel, but they aren't so important. You will probably want to buy a set of mixed thickness glazing packers before you start this (I think I got some from screwfix or Wickes, I forget which). Refit the beading.
If the door has been drooping for some time, you probably won't be able to bend it completely back into the original shape, but do it just enough so the catches work again. Probably also best to defer this whole task until weather is warmer if you can - door may bend back more easily without risk of breaking the uPVC, not to mention that it's not good to have the door open or the panels removed for too long when it's minus something outside.
No, the door is fine. I have now given the horizontal adjusting screws a turn, and all seems to be well. The door simply wasn't far enough over for the catch to engage properly.
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