I have a sunroom that was built on top of an outside deck. It is made of aluminium and glass walls with a curved glass ceiling. Anyway, I think there has been a bit of settling recently because the latch om the doorknob is now out of line with the strikeplate by about 1/2 inch. How would I repair this? The strikeplate is cut into metal and if I move it up I will have nowhere to put the bottom screw. Right now the door won't even stay closed because it doesn't latch. I hope someone can help. Thanks.

I don't think the door is your problem. If this deck is settling and causing the door to shift, I would start there and that I can't help you with over the net.

The foundation would have to be checked. Check the constuction of the deck etc.

Was going to build a "Sunroom" on my cement deck untill they told they would not be responsible for it unless they poured a new footing. This ran the cost up more then I could afford.

I would recommend getting a contractor or even two to check it and make recommendations. The door could only be the start of future problems.