Pathology Flashcards
Asbestos
Types: Chrysotile (white), Amosite (brown), Crocidolite (blue)
Found in: AIB, floor tiles, lagging, cement sheets
Key Regs: Control of Asbestos Regulations 2012
Survey Types: Management survey / Refurb & Demolition
Duties: Identify, manage risk, ensure competent removal
Biodeterioration
Definition: Damage caused by biological agents (fungi, bacteria, insects, etc.)
Examples: Wet/dry rot, beetle attack (woodworm), mould, lichen on masonry
Conditions: Damp, poor ventilation, organic materials
Remedies: Moisture control, biocide treatments, material replacement
Building Defects – Case Law
Dutton v Bognor Regis UDC (1972) – LA liable for negligent inspection
Murphy v Brentwood DC (1991) – Reversed Dutton; no liability for pure economic loss
Pirelli v Oscar Faber (1983) – Limitation period starts when damage is discoverable
Heart of England NHS v Wolverhampton CC (2016) – Contractor liable for fire safety defects
Building Elements
Substructure: Foundations, ground floor slabs
Superstructure: Walls, roof, upper floors, stairs
Finishes: Plaster, paint, cladding
Services: M&E, drainage
External Works: Paving, fencing, access roads
Common Defects
Damp (rising, penetrating, condensation)
Cracking (subsidence, thermal, shrinkage)
Roof leaks, defective rainwater goods
Movement: Heave, settlement, thermal expansion
Spalling, corrosion, poor detailing
Damp
Types:
Rising (via capillary action, DPC failure)
Penetrating (through walls, roof defects)
Condensation (moisture in air on cold surfaces)
Diagnosis: Visual inspection, damp meter, salts analysis
Remedy: Repair source, improve ventilation, install/repair DPC
Practical Building Repair
Approach: Diagnose → Stop cause → Repair fabric
Principles:
Use like-for-like materials
Ensure compatibility (e.g., breathable render on solid wall)
Prioritise minimum intervention
Examples:
Repointing with lime mortar
Timber splice repairs
Localised damp proofing
Damp
Identification: Staining, peeling paint, musty smell, salt deposits
Cause: Rising damp (DPC failure), penetrating damp (leaks), condensation (poor ventilation)
Remedial Work:
Repair DPC or install chemical DPC
Fix external defects (e.g. gutters, flashing)
Improve ventilation (e.g. trickle vents, extract fans)
Timber Decay (Wet/Dry Rot)
dentification: Softened timber, cracking, fruiting bodies, musty smell
Cause: Prolonged damp conditions, poor detailing, leaks
Remedial Work:
Remove source of moisture
Replace affected timber
Apply fungicidal treatment
Improve ventilation
Cracking
Identification: Vertical, horizontal, stepped, diagonal cracks in walls
Cause: Structural movement (subsidence, settlement, thermal expansion), shrinkage
Remedial Work:
Monitor if active
Underpinning or strengthening if structural
Masonry repairs, re-pointing, crack stitching
Roof Defects
Identification: Leaks, slipped tiles, water stains on ceilings
Cause: Damaged tiles/slates, poor detailing, failed flashing
Remedial Work:
Replace broken tiles
Refix loose battens
Reseal or replace flashings
Check and clear gutters
Corrosion (e.g., steelwork or wall ties)
Identification: Rust staining, bulging masonry, delamination
Cause: Water ingress, chemical attack (chlorides), carbonation
Remedial Work:
Expose and clean corroded metal
Replace wall ties if needed
Repoint with appropriate mortar
Apply protective coatings
Spalling
Identification: Flaking or breaking of brick/stone/concrete surface
Cause: Freeze-thaw action, corrosion of reinforcement, salt crystallisation
Remedial Work:
Cut out and replace affected areas
Use breathable finishes/mortar
Apply water repellent if appropriate
Condensation & Mould
Identification: Black mould, water droplets, especially on cold surfaces
Cause: Poor ventilation, lack of insulation, occupant behaviour
Remedial Work:
Improve ventilation (MVHR, extractor fans)
Upgrade insulation
Educate occupants on moisture control
Tools & Equipment for Defect Diagnosis
Visual Inspection
Torch, mirror, binoculars, camera
Initial, most common method for identifying signs of defects
🌡️ Moisture Measurement
Moisture Meter: Measures surface and sub-surface moisture (conductive/resistance type)
Hygrometer: Records air humidity & temperature — used for condensation risk
Salt Analysis Kit: Identifies hygroscopic salts (nitrates/chlorides) in damp diagnosis
🎯 Movement Monitoring
Crack Width Gauge: Measures width and changes over time
Tell-Tales: Fixed across cracks to monitor structural movement
Plumb bob / spirit level / laser level: For alignment and verticality checks
📏 Thermal & Insulation
Thermal Imaging Camera: Detects heat loss, thermal bridging, moisture ingress
Boiler flue/insulation checks: Can reveal cold spots or missing insulation
🧱 Structural & Material Testing
Rebound Hammer (Schmidt Hammer): Assesses surface hardness of concrete
Cover Meter / Rebar Scanner: Detects steel reinforcement location and depth
Endoscope/Borescope: Inspects inside cavities and voids
Typical Victorian Building Defects
🧱 1. Damp Penetration
Solid walls (no cavity) allow moisture ingress
Lack of or failed damp-proof course (DPC)
Poorly maintained rainwater goods
Remedy:
Repair render, re-point with lime mortar
Install/repair DPC
Maintain gutters and downpipes
🌬️ 2. Condensation & Poor Ventilation
Originally built to “breathe” – later modifications often block airflow
Sealed windows and blocked chimneys restrict ventilation
Remedy:
Reintroduce passive ventilation
Install extract fans in wet areas
Use breathable finishes
🧱 3. Structural Movement / Cracks
Shallow foundations and clay subsoils cause settlement or heave
Bay windows and extensions often more vulnerable
Remedy:
Monitor cracks, underpin if structural
Crack stitching and repointing
🪵 4. Timber Defects
Wet/dry rot in floor joists, roof timbers
Woodworm common in roof spaces and floors
Timber lintels prone to decay
Remedy:
Improve ventilation and isolate timber from damp
Replace/repair infected timber
Apply treatment if needed
🧯 5. Fireplaces & Chimneys
Chimney breasts may be unsupported after removal
Defective flashings cause leaks
Soot build-up, flue defects
Remedy:
Structural support for removed chimney breasts
Repointing and flashing repairs
CCTV flue survey if reused
🏚️ 6. Roof Defects
Slipped slates, corroded nails (“nail sickness”)
Lead flashings may be perished
Poor insulation
Remedy:
Re-fix or replace slates
Replace flashings with new lead
Improve loft insulation (ensure ventilation)
