[jnwatson]

The first time I built anything to survive outside (a ramp to a shed), I learned this the hard way.

Even with a decent amount of planning for the elements, it lasted 3 years. It really makes one appreciate how special it is that this lump of flesh might survive 70 or 80 years.

[huffmsa]

Your lump of flesh is constantly replacing and repairing it's components

[choonway]

and why can’t civil structures do the same?

[huffmsa]

They can and should. That's the sign of a happening place. When reconstruction and replacement stops, it's a sign of decline