The signs of a rotting window are unmistakable. The wood becomes soft and spongy to the touch, and crumbles easily in the hands when dry. Whatever the cause, homeowners may save money by knowing how to repair rot and decay on wooden windows. Basic steps include applying a primer, applying an epoxy, and then finishing the project with paint or stain, and sealer.

Nature is a wooden window's most dangerous enemy. Sun and moisture both cause wear, but moisture is the principal assailant. Dry rot is caused by a fungus, which loves to grow in airtight, wet conditions, like the space between a failed coat of paint and a wooden sill. Damaged finish, peeling caulk, and excessive moisture may all be reasons for windows to begin to decay.

To begin the repair, homeowners must remove all rotten wood. With a paint scraper, or with a utility knife, old paint, caulk, and rotten wood should be scraped away, until new wood is reached. The new wood must be both coarse and dry before painting, so homeowners will have to sand, and dry the new wood beneath the rot.

After prepping the surface, homeowners should apply a primer. Depending on the brand, the preparatory liquid is either known as primer, or consolidant. It usually consists of two liquids, with equal parts of each mixed together. The primer, or consolidant, pre-treats the surface, by soaking into the wood grain.

Applying primer becomes more involved if the rot goes down to the frame. In this case, a homeowner should drill small, sloping pits, into which he or she should inject primer. When primer has been applied, it should cure for the time period specified in the manufacturer's instructions.

When the consolidant has completely cured, the epoxy may be applied. The best application tool is a trowel, so that the epoxy may be pressed into all gaps in the wood's surface, and into all damaged areas. When cured, according to the manufacturer's instructions, the epoxy should be sanded, and then either primed and painted, or stained. After painting or staining has been completed, the wood should be covered with waterproof sealer.

Learning how to repair rot and decay on wooden windows is an uncomplicated process. Homeowners who are willing to invest a little time and elbow grease will easily complete the repair. The cosmetic damage will be contained, and homeowners will save money on labor costs, by completing a few simple steps.