Outdoor structures are exposed to heat, cold and rain, which causes the expansion and contraction of the timber, creating cracks and splits.
Cracks continue to move with the weather, so these areas of damage and any timber joints in the deck that have opened up should be filled to avoid additional moisture problems and insect infestation.
If old posts are cracked, check for rot before filling or replace posts if they are not structurally sound.
Sand and oil the area once the filler has cured to prevent further damage from occurring.
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Use a putty knife or spatula to work timber filler into the damaged area, levelling it flush with the surface. Choose a flexible filler specifically designed for outdoor use, as ordinary timber putty will quickly crack.
Once the filler has cured, remove the excess using a flexible sanding block with 60 grit abrasive paper, then feather the edges with 180 grit paper. Wipe off any dust from the surface using a clean, dry cloth.
Use a paintbrush to apply at least two coats of decking oil to the post to prevent moisture penetration and conceal the repair. TIP For painted posts, apply primer, then two coats of exterior paint.