Why do old homes start falling apart?
Because nature is cold and uncaring, and any structure that doesn’t get maintenance will eventually fall before its wrath. That sounds dramatic, but many of humanity’s greatest structures would disappear in a century without maintenance. And most homes are built to a much lower standard of durability.
Mold will eat through homes that aren’t maintained and looked after. Termites and rot will do the same. And if those don’t do the trick, eventually rain, soil humidity, and temperature changes will start damaging the house’s structures. Usually, old homes start falling apart due to a combination of all of the above, something that happens even faster when the home wasn’t built to high standards, to begin with.
Maintenance can delay or prevent most of those issues. Rot and mold can be removed and controlled. And humidity can be managed with the help of damp proofing Kent professionals, as seen on http://www.jhgarlickltd.com/Damp-Proofing.htm. But if the house is abandoned or its owners aren’t maintaining it, nature will do its thing and start breaking things down.