You can treat wood gutters with a sealant every few years to help protect them from the elements. However, if they are damaged, they will need to be replaced. If you're looking to seal your wood gutters, we recommend using a water-based sealant that is specifically designed for use on wood. Be sure to follow the instructions on the bottle carefully, and always test the sealant in a small, inconspicuous area before applying it to the entire gutter. Applying too much or not enough of the sealant can both cause problems, so it's important to be precise in your application.