Pressure-Treated Wood Jamb Repair

• 1). Drill half-inch holes into the wood jamb about 6 inches above where the rot stops, then drill across horizontally every 2 to 3 inches. Chisel out the rotted jamb section using your hammer and wood chisel. Make a clean cut and remove any jagged pieces.
  
  
• 2). Pry off any trim with your small crowbar and remove the threshold using your screwdriver, if it's screwed down, or pry bar, if it's nailed down. Chisel out any rot you find.
  
  
• 3). Cut new pressure-treated wood the same size as your old jamb using a skill saw.
  
  
• 4). Screw new pressure-treated wood underneath the threshold using drywall screws. Place silicone over the screws after you tighten them with the cordless drill. Silicone the two joints where the old door jamb and the new pressure-treated one meet up.
  
  
• 5). Replace your threshold and screw it down on top of your new pressure-treated lumber base. Replace any threshold or door jamb weatherstripping.
  
  

Epoxy Treatment for Rotted Door Jambs

• 1). Put on gloves, the respirator and eye protection and chisel out any rot. Apply an epoxy sealer to affected areas using a paintbrush. Let the area dry for about one hour.
  
  
• 2). Prime the area with epoxy primer, let dry for about one hour and apply epoxy mortar to fill up any large holes. Use a plastic injector tube to insert the epoxy deep into the holes. Let dry for several hours.
  
  
• 3). Treat the affected area with Boron, which is specially designed to prevent insect or water rot. Let dry for several hours, then prime and paint your newly repaired door jamb.