I have a sagging first floor in the duplex I own. Age approx 100 years with a crawlspace for the basement. What should I do? Leave alone or get someone one to look at it? Is this even a problem. The sag (approx 1/2 to 1 inch - water rolls to this area if washing floors) is more a gentle slope and appears to be where the crawl space is. It has not change in the last two years (I owned it for 2years). And only sags where the crawl space is or in the kitchen (the living room, bathroom and spare room on first floor appear level). There is no problems of sagging floors on the second floor or with any doors/doorframes closing or cracks in the walls from shifting. Thanks for any help.
This is one of those 'what is causing the problem' questions. I would suggest a good inspection by a qualified person. It may be 'nothing' and you can live with it or, it may be serious damage to joists or supports. Check for water, insect, and contractor damage. Some plumbers are prone to cut joists to the extent the support system is in trouble.