Timber windows – rotted sill

Cause

Water sits on the sill if the slope is not sufficient to shed it 

Repair

  • if only a section of the sill is damaged, cut out the damaged section and replace it
  • if the rot is significant, consider replacing the window with a second hand unit in good condition

Cause

Water is getting into the sill/jamb junction 

Repair

  • if only a section of the sill is damaged, cut out the damaged section and replace it
  • if the rot is significant, consider replacing the window with a second hand unit in good condition

Cause

Poor initial substrate preparation

Repair

  • if only a section of the sill is damaged, cut out the damaged section and replace it
  • if the rot is significant, consider replacing the window with a second hand unit in good condition

Cause

Oil-based (alkyd) paint was applied over water-based (acrylic) paint

Repair

  • if only a section of the sill is damaged, cut out the damaged section and replace it
  • if the rot is significant, consider replacing the window with a second hand unit in good condition

Cause

The sill was painted a dark colour, increasing thermal expansion/contraction of timber 

Repair

  • if only a section of the sill is damaged, cut out the damaged section and replace it
  • if the rot is significant, consider replacing the window with a second hand unit in good condition

Cause

There was moisture absorption into timber end grain because of inadequate priming

Repair

  • if only a section of the sill is damaged, cut out the damaged section and replace it
  • if the rot is significant, consider replacing the window with a second hand unit in good condition