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Surveying 17th-Century Oak Framed Buildings: Key Issues, Risks and Considerations
Wednesday 29th January 2025
Carl O'Boyle BSc MRICS FCIOB MFPWS
When surveying a 17th-century oak-framed building, several key issues and potential disadvantages need to be carefully assessed, as these properties often have historical, structural, and maintenance complexities. Here’s a guide to help you:
Key Issues to Look Out For:
Structural Concerns -
1. Timber Decay
• Rot: Look for signs of wet rot or dry rot, especially where the frame meets the ground or around windows and doors.
• Insect Infestation: Common pests include woodworm (e.g., common furniture beetle) and deathwatch beetle, particularly in old hardwoods.
• Check for hollow-sounding or crumbly timber sections.
2. Frame Movement
• Many oak-framed buildings show signs of historic movement. Check for distortions, leaning frames, and joint separation.
• Assess for ongoing movement, which could indicate foundation issues or frame instability.
3. Joint Failures
• Traditional mortise and tenon joints may have weakened over time. Look for gaps, missing pegs, or poorly executed repairs.
4. Foundation Issues
• Older buildings often have shallow or no foundations. Check for differential settlement or subsidence, especially on clay soils.
Water Ingress and Damp
1. Rain Penetration
• Examine external cladding (brick infill, wattle and daub, or panels) for cracks or gaps that allow water ingress.
• Assess the roof condition (thatch, tiles, or slates) for leaks.
2. Ground-Level Damp
• Older buildings rarely have damp-proof courses. Check for rising damp, particularly at timber bases and wall infill panels.
3. Gutter and Drainage Issues
• Look for defective gutters, downpipes, and surface drainage that could direct water toward the structure.
Infill and Wall Panels
1. Wattle and Daub
• Check for cracking, bulging, or detachment of panels. These can weaken over time and need specialized repair.
2. Brick or Render Infill
• Examine for cracking and incompatibility between modern repairs and the original materials, which can cause stress on the timber frame.
Roof Structure and Covering
1. Sagging Roofs
• Look for deformation or sagging, which could indicate roof spread or deterioration in timbers.
2. Thatch Maintenance
• If the roof is thatched, consider the thickness and condition of the thatch, as it requires periodic replacement.
Heating and Energy Efficiency
• Older buildings often lack modern insulation.
• Check the condition of chimneys, fireplaces, and ventilation, as they are integral to maintaining the building’s health.
• Ensure heating systems are functional and safe, given the challenges of retrofitting modern systems.
Alterations and Repairs
• Inspect for past repairs. Poor-quality modern repairs or inappropriate materials can exacerbate issues (e.g., use of cement instead of lime mortar).
• Look for signs of listed building compliance if the property is listed.
Disadvantages of Buying an Oak-Framed Building
1. Ongoing Maintenance
• Historic buildings require constant maintenance to prevent decay and preserve their character.
2. Cost of Repairs
• Repairs must often use specialist techniques and materials, which can be costly (e.g., lime mortar, hand-cut timber).
3. Planning and Conservation Restrictions
• If the property is listed, you may face restrictions on alterations and need consent for repairs.
4. Thermal Performance
• These buildings are often draughty and poorly insulated, leading to higher heating costs. Retrofitting insulation can be challenging without affecting the structure.
5. Insurance and Financing
• Specialist insurance is required for historic buildings, which can be expensive. Some mortgage providers may be cautious about lending on older properties.
6. Pests and Damp
• Historic timber-framed buildings are more susceptible to pest infestations and damp issues, which can lead to significant structural damage.
Summary
While oak-framed buildings offer unique charm and historical significance, they come with inherent risks and ongoing responsibilities. During your survey, focus on identifying the following:
• Evidence of structural movement or decay.
• Signs of water ingress or inadequate drainage.
• Compatibility of previous repairs and the condition of historic materials.
• Planning or conservation implications.
The findings should guide your client on whether they’re prepared for the responsibilities of owning such a property and the associated costs.
