Exterior Woodwork Repair Guide

Professional exterior woodwork repair focuses on "splicing" or "filling" rather than total replacement. This approach preserves original features, particularly on period properties, while ensuring the roofline remains watertight and structurally sound for years to come.

What Does the Work Involve?

• Initial Inspection: Probing timber with an awl to identify soft spots, "alligatoring" paint, and failed joints.
• Rot Removal: Cutting out decayed sections back to sound, "bright" wood to prevent the spread of fungi.
• Fungicidal Treatment: Applying a liquid wood hardener or preservative to the remaining timber to kill dormant spores.
• Splicing or Filling: Fitting new pre-treated timber "Dutchmen" or using high-performance two-part epoxy resins to rebuild the profile.
• Surface Preparation: Mechanical sanding to create a "key" for new coatings and rounding off sharp edges where paint is prone to thinning.
• The Coating System: Applying a specific exterior system, usually consisting of a knotting agent, primer, undercoat, and flexible topcoat.
• Sealing: Using high-modulus silicone or polymer sealants at the junctions between timber and masonry or glazing.
• Gutter Check: Inspecting and clearing adjacent gutters to ensure water is directed away from the newly repaired timber.

Typical Costs

Prices for exterior woodwork repair vary based on the height of the property and the extent of the rot. Working at height usually requires a cherry picker or an alloy tower, which adds to the initial setup cost.

Note: If more than 30% of a fascia board is rotten, your tradesperson may recommend a full replacement rather than a repair, as the labour cost of intricate splicing can eventually exceed the cost of new timber or uPVC.

How Long Does It Take?

• Minor Sill or Fascia Patch: 2–4 hours. This usually involves one visit for prep/filling and a second for painting.
• Multiple Spliced Repairs: 1–2 days. Sufficient time is needed for epoxy resins to cure fully before sanding and painting.
• Full Gable End Overhaul: 2–3 days. This includes scaffold erection, stripping back old paint, and multi-stage coating.

DIY or Professional?

Small repairs to ground-floor windowsills are well within the reach of a confident DIYer using a two-part wood filler. However, working on fascias and soffits involves significant heights and often requires working around power lines or delicate guttering. Professional carpenters or roofline specialists have the correct access equipment and high-build resins that last far longer than standard DIY fillers. Furthermore, any work involving gas flues or electrical cables near the roofline must be handled by qualified professionals to ensure compliance with safety standards.

Choosing the Right Tradesperson

• Check Specialisms: Look for a carpenter or a "roofline specialist" rather than a general handyman for structural timber repairs.
• Insurance: Ensure they hold Public Liability Insurance that specifically covers "working at height."
• The "Resin" Question: Ask if they use two-part epoxy resins or just standard wood filler; epoxy is essential for durable exterior repairs.
• Questions to Ask:
  • "Do you treat the end-grain of the new timber before installation?"
  • "Is the cost of scaffolding or tower hire included in your quote?"
  • "What paint brand do you use, and how many coats are included?"

UK Regulations

• Work at Height Regulations 2005: Professionals must use stable platforms (towers/scaffolding) rather than just ladders for extended repair work.
• Building Regulations Part L: If you are replacing a significant amount of cladding or roofline, you may need to consider the thermal implications, though this rarely applies to minor repairs.
• Conservation Areas: If your home is listed or in a conservation area, you may be legally required to repair timber rather than replace it with uPVC. Always check with your local planning office.

Common Problems

• Painting Over Wet Wood: If a repair is done in damp weather, moisture gets trapped under the paint, causing it to blister and peel within months.
• Ignoring the Guttering: Rot in fascias is almost always caused by leaking or blocked gutters; if the gutters aren't fixed, the new wood will rot just as fast.
• Using the Wrong Filler: Standard interior "poly" fillers absorb water and will pop out of the wood during the first frost.
• Unprotected End-Grain: The cut ends of timber act like straws for moisture; they must be saturated with preservative and primer before being joined.

Frequently Asked Questions

Is it better to repair timber or switch to uPVC?

Timber is more aesthetically pleasing for traditional UK homes and is more environmentally friendly if maintained. However, uPVC is virtually maintenance-free. If your timber is structurally sound, repair is cheaper; if it is riddled with rot, uPVC replacement may be more cost-effective long-term.

Can I repair rotten wood in the winter?

It is difficult. Most high-performance resins and paints require a minimum temperature (usually 5°C or 10°C) and dry conditions to cure. Winter repairs are often "emergency" patches that may need to be redone properly in the spring.

Why is my new paint peeling off the repair already?

This is usually due to "moisture trap." If the timber wasn't bone-dry when painted, or if a knotting agent wasn't used on new timber sections, the natural resins or moisture will push the paint off the surface.

How do I know if the rot has reached the rafters?

A professional will look for "softness" behind the fascia board. If the ends of the rafters (the "feet") are soft to the touch, they will need to be "sistering" (reinforced with new timber), which is a more significant structural job.

Do I really need scaffolding for a small fascia repair?

For a quick 30-minute task, a secured ladder may suffice. However, for sanding, filling, and multi-coat painting, a stable platform is a legal requirement for most businesses to ensure the safety of the tradesperson.