Repair Rotted Window Frame

GoJo Geoff
by GoJo Geoff
2 Materials
4 Hours
Painting our house was going well until I came across this rotted out window frame. Follow my instructions for a perfect fix on something many would consider trashing and replacing.
Trash Or Restore It?
Lots of damage to this window sash begs the question, " do I trash it or restore it? Does restoring mean an expensive joinery job, or is their a simpler way?
Remove the Rot
Good news - there is a way to restore the window.
Start by Removing the rot all the way back to the original unrotted timber. If you don't do this the job will not last and the rot will continue to eat into the window frame.
A Simpler Way
I decided to bog this damage but first I needed to get things straight, quite literally. A 2x1 would do, with protection from the sticky bog via masking tape.
Straight Edge
Clamp the straight edge to the sash. This will give the correct finishing line and bypass a lot of finishing off fuss down the track.
Bog It
Use a good quality two part builders bog or similar
Mix It
Mix the bog according to the instructions
Fill It
After removing all the rotted timber apply the bog and make sure there is very good contact with it and the remaining wood.
Trowel It
Use trowels and straight edges to fill out any imperfections after the main straight edge is removed.
Scrap It
Another handy tool for cleaning up excess filler is this 4 inch blade.
Sand It
Sand off the bog to create as smooth a finish as possible
Finish It
Use finishing plaster to leave the job looking fantastic
Sand & Paint It
Sand and Paint to restore the sash to something like it's original appearance. Amazing results, considering what started out as an impossible looking task.
All the steps together in one video!
Suggested materials:
  • Builders Bog (Filler)   (Bunnings)
  • Finishing Plaster   (Bunnings)
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