How to repair rotten windows & doors
There is an easy way to make rotten or rotting windows and doors look like new
The majority of rot attacks in windows and doors and their frames is 'wet' rot. The symptoms of this are softening of the wood, a darker colour where paint has flaked off and cracks appearing along the wood surface. You can test for rot by poking a small, pointed tool (a bradawl or penknife, for example) into the surface. Where the wood is rotten, the tool will sink easily into the wood.
The first stage in repairing a rotten window or door is to cut out all the softened and damaged wood. Using a sharp chisel, keep going until you are certain that you have reached solid wood. Treat all the exposed wood surfaces with Cuprinol Ultimate Repair Wood Hardener, which must be left to harden for at least 6 hours. This binds the surface and provides a solid base for the subsequent filler. Clean the brush in methylated spirits.
While the hardener is drying, re-glue any loose joints in the door or window, putting new wedges into a loose mortise-and-tenon joint in a door and adding glued dowels at right angles to reinforce a bridle joint in a window. Cut off protruding wedges or dowels once the glue has set.
If very large sections of wood are involved (such as most of a rotten window sill), it might be necessary to cut out a section of the sill with a saw and let in a new piece of wood, cut to size. The exposed ends of the existing sill should be treated with Cuprinol Ultimate Repair Wood Hardener as in Step 2; the new wood should be treated with Cuprinol Wood Preserver Clear.
Mix up the two-part Cuprinol High Performance Wood Filler and apply to the surface with a filling knife (or the plastic applicator that is provided), leaving it slightly proud of the surface. If you are filling deep holes, you should put screws part way in first to 'anchor' the filler.
Once the filler has set, it can be planed, chiselled and sanded until it is smooth and flush with the existing surface. Make sure any surrounding paint is sound and clean (and lightly sanded to provide a key) before applying a new paint finish over the sanded filler to match up with the surrounding surface.
Follow us on: