Window sill and frame rot is a common problem because water leaks in around the paint/caulk and the heat from the sun cooks it all up into a perfect environment for rot fungi. To the right, we show a picture of mild rot where the moisture has gotten under the caulking and a picture of severe rot where moisture has simply gotten under the paint. The rot may also get into the window/door framing.
The sequence for repair is basically as follows:
1) Remove any loose wood.
2) Make sure the wood is reasonably dry.
3) Scrape off the paint around the affected area, or, better yet, the whole sill.
Deteriorated shutters and doors and door sills can be repaired using similar techniques.
While termites are the home owner’s main concern, there are a variety of insects that can and do penetrate the wood. Other insects such as a variety of ants, beetles, and bees often simply use the wood for home and breeding space. Their damage is not so extensive but does provide access for water to get into the wood. It’s not uncommon to see extensive fungal rot in areas where insects have penetrated.
Termite and boring insect tunneling are often on mainframes or sill timbers, and in due course will cause major structural damage. Most often the damage is in inaccessible areas. Replacing the timber is not always an option, and even if it is, a replacement can be expensive. What needs to be done is to restore structural strength to the timber, and to seal the wood so that bacteria and fungi (and insects) won’t have access to the interior.