Carefully check your window frame to have an accurate assessment of the damage. For a window frame with more than 10 percent of damage, it is best to replace the entire window to ensure the safety and protection of your home. Unless you are adept with construction work and homemaking jobs, replacing an entire window generally requires a construction expert.
Do-it-yourself ways for repairing windows are primarily geared towards small wooden window frames and mostly those that utilize single-paned glasses. If you have large panes and intricately constructed windows frames, whether they are made of wood or another material, it is much better to ask a professional to do the job to avoid security risks and creating more serious home damage.
Apply wood preservative over the entire wooden window frame to protect it from getting further damaged and rotten. Fill in the hollowed area with wood putty or epoxy. For larger hollows, you may have to build up the putty in layers that look like the actual frame so that the putty blends with the color and texture of the window frame. Let this dry for about 24 to 48 hours, then use a medium-grit sandpaper to smooth out the filled-up areas of the frame. If you have metal or vinyl window frames, minor damage and small cracks are repairable through DIY kits with paste-like substances like PVC glue that can serve the same role as the putty used in wood. In cases where there are larger damages on the frames, it is best to replace the window entirely.