[jester]

It all depends on where you are in the world with climatic conditions.

There are wooden and log cabins in California and other parts of the southwest that are over 100 years old, I mean that is how long they have been ocupied.

If there is heavy snow and it has a flat roof of wood it will either rot or colapse from snow buildup. A peaked roof will shed snow and debris more.

Concrete with steel reinforcing, if the metal is exposed it will rust which will cause the metal to swell and thus crack the concrete.

There are stone buildings here in the desert that are over 100, some 150 years old.

Buildings at former airbases in the desert have been abandoned since the early 90s, they still stand, same with some by March Air Base, they still stand and have been turned into an Urban War Center.

If the weather changes alot from winter to summer you may have more deterioration.

If an area is WET you will have more rot.

Earth Activity, soft soil, buildings will settle and slip off their foundations, or their foundations will crack.

Earthquakes, well in a T2K world without maintenance, and with the odd earthquake, say a good one every 10 years or so, give alot of the structures no more than 30 years before they would start to fall.

Floods, ocean activity, all of it would come into play. So, you have to look at what the climate and geological conditions are in your area or the area of your campaign.

Also, 2 things that also destroy,

Water/ICE. Water gets into places, if it freezes it causes cracks even in concrete.

Plants, their roots will crack concrete, or if dirt builds up and then seeds take root, they will destroy buildings and concrete as well, but it would be cool too. Imagine a house that is still there but a tree has started growing through its center?