Wood is a common and popular material for interior design and construction. Because it is organic, it is also prone to damage and deterioration from moisture, heat, light and other factors. If you noticed that your wooden door frame began to root in some places, you don't have to replace the whole door. With the right tools and a small amount of wood putty or epoxy, you can patch the affected area and save your door.
Locate and inspect the damage on your door frame. If you discovered the rotting is in an early stage, you can easily repair the affected area with fillers. However, if the damage by rotting is too severe, it is best to replace the whole frame to prevent it from crumbling and collapsing.
Remove the soft parts of the rotten wood with a chisel or similar metal tool. Make sure to remove all the affected wood and chisel all the way to the healthy parts. You will recognise the rotted wood because it's loose, soft and has a darker colour than the rest of the frame.
Apply two to three thick coats of wood hardener to the chiselled-out area. Use a wide paintbrush, go slightly over the edges of the area and don't miss a spot. The wood hardener is usually an epoxy-based sealer than penetrates through the wood surface. Let the area dry completely for a few hours.
Fill the hole in your door frame with an epoxy or wood putty. Use a putty knife to apply the substance, shape it and make it even with the surface of the door frame. Leave it to dry and harden for a while, meanwhile checking if the putty shrank, in which case you need to apply more. Remember that the filled area needs to be seamless and unnoticeable, like the wood of the door frame that still is intact.
Treat the area with fine grain sandpaper to make it smooth and blend in with the rest of the wooden surface.
Apply a coat of primer on the whole frame and leave it to dry. Then paint the door frame with the colour wood you want. Leave it to dry, and don't touch it for 24 hours.
Check home improvement stores for additional wood restoration products you can use. Prevent future rotting by regularly applying protective paint to the surface of your door frame.
Wear thick and durable working gloves when you use a chisel.