Step 2 Clean up damaged area to remove dirt and spider webs. Check broken piece will fit in place. If not, cut a new sliver of timber to roughly fit in place. Apply glue to face of door frame.
Put broken or replacement piece in place and hold with a clamp using an offcut of timber to give even bearing to all pieces.
Step 4 Use fine 15mm or 20mm nails to reinforce timber. It’s best to predrill to avoid splitting the already broken timber. Punch nail heads below surface. Let glue dry.
Step 5 Mix a small quantity of 2-part resin filler and fill gaps between door and patched pieces. Do not fill too high, as you will have to sand it off. Also, do not get filler into cavity that takes roller assembly or you will have trouble fitting it.
Step 6 When set, sand back filler using belt or orbital sander. Depending on surface, you may need to repeat Steps 5 and 6 for a smooth surface.
Step 7 Paint repaired area or whole door with primer, sealer and undercoat, followed by 2 coats of enamel to match existing doors.
Step 8 Fit new roller assemblies at both ends of door and adjust so roller is nearly fully up. Screw in place, then stand door back in its position on tracks. Use a screwdriver to raise or lower the rollers at each end so that door is in alignment and rolls smoothly.