What caused window sill rot on the inside of my house?

Answer by  Skullwing (746)

This is more than likely caused by high humidity and its accompanying mold infestation, or alternating periods of humidity and very dry air. Mold puts roots in the silicone rubber, weakening it and making it porous, thus causing it to rot. Tree roots do this to concrete, same results.

Answer by  hahagal (983)

One of the most common problems is the moisture that is from improper installation and weakening of the weathering strips on the window sill.

Answer by  yeswanth (235)

If a wood is enough cool to live by a termite, it will happily start living there by eating the same which leads to rot. It comes from the nearby sand pot or flower vase and multiple very fast manner. Use kerosene to kill those termites and keep dry the place.