Using Wood Filler to Repair and Prevent Rot of Wooden Stairs

Lead Image for Using Wood Filler to Repair and Prevent Rot of Wooden Stairs
  • 1-4 hours
  • Beginner
  • 30-70
What You'll Need
Liquid Wood Hardener
Drill and Bits
Wood Filler (Epoxy or Polyester)
Paint and Paintbrush
Mixing Container
Putty Knife
Rasp Tool
Wood Chisel

Wood is an amazingly durable material that can be used for a lot of projects including building wooden stairs. Problems arise though when the wood ages and gets prone to crack- or hole-formation. When cracks and holes are formed in wood, water tends to settle in them and may cause the wooden stairs to rot. There are steps you can take to repair and prevent the rot of wooden stairs. The tools and materials you need and step-by-step instructions are below.

Remove Wet Wood

Using a wood chisel, remove any wet wood around affected areas in the wooden stairs.

Inject Liquid Wood Hardener

Use an awl to inspect the affected areas in the wooden stairs by poking the areas lightly and looking for areas in the wood that are as solid as the unaffected areas. Once you’ve found those solid areas, use the drill and bits to drill several 3mm holes around the affected areas. Inject the liquid wood hardener in the holes.

Apply Wood Filler

Mix the epoxy or polyester filler. Mix only the amount that you require immediately as filler dries up really quickly and any dried up filler will have to be thrown away. Once you have your filler ready and mixed, use the putty knife to apply the filler into the affected area in the wooden stairs and shape it as required. Apply pressure with the putty knife to make a compact fill but not as much as to compress it a lot as filler shrinks when it dries up and will leave room in your wooden stairs’ filler-shaping.

Even-out the Wood Filler

Using the rasp tool, even out and remove any excess filler. Make sure you do this quickly before the filler completely dries up otherwise it will not be possible to do so.

Shape and Blend the Repaired Patch

Use sandpaper to further shape the filled patch in the wooden stairs. Do some fine shaping and blending using different types of sandpaper. Use medium sandpaper at first and use fine sandpaper to blend the filled patch into the surrounding un-affected wood.

Paint the Affected Area

Once you have finished patching the affected area in the wooden stairs, touch it up with some primer and paint of appropriate color that matches the wood.


Prevention of rot in wooden stairs is very important and can save you from going through the whole repair process often. To prevent wooden stairs to rot keep inspecting the wood for any peeling paint or finish if it was applied when the wooden stairs were first installed. Seal initial cracks around joints in the wooden stairs with caulk. Apply a preservative on wooden stairs after priming and before the finish. Make sure the wooden stairs get enough ventilation in whichever part of the house they are in.