BUILDING SURVEYING IN CONSTRUCTION�

Dr Adewale Abimbola, FHEA, GMICE.

www.edulibrary.co.uk

Aim & Objectives

1. Identify common defects in foundations, walls, and chimneys.
2. Analyse the causes of these defects and their impact on building integrity.
3. Evaluate appropriate repair and prevention strategies for external envelope defects.

At the end of the lesson, the students should be able to:�

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Defects to External Envelope

Defects to External Envelope

Introduction

• Properties require repairs for various reasons, and building surveyors play a crucial role in this process.
• Understanding the need for repairs and the surveyor's responsibilities is essential for maintaining the built environment.

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Reasons for property repairs:

• Natural wear and tear over time
• Weather-related damage, Structural issues or subsidence
• Outdated building materials or systems
• Changes in building regulations or safety standards
• Improving energy efficiency and sustainability
• Enhancing property value or marketability

Roles of the building surveyor:

• Conducting thorough property inspections
• Identifying defects and potential issues
• Preparing detailed condition reports
• Recommending appropriate repair strategies
• Estimating repair costs and timelines
• Advising on compliance with building regulations
• Overseeing repair works and quality control
• Providing expert witness services in legal disputes

Foundation

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CAUSES AND SOLUTIONS TO FOUNDATION DEFECTS - SETTLEMENT

CAUSES: SEASONAL FACTORS

• Expansion and contraction of clay soils due to moisture changes
• Frost heave in winter
• Drought causing soil shrinkage in summer

• Install proper drainage systems
• Use moisture-resistant landscaping techniques
• Apply soil stabilisation membranes
• Create consistent soil moisture levels

SOLUTIONS: MINING ACTIVITIES

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• Subsidence due to underground excavations
• Collapse of old mine shafts
• Vibrations from nearby active mining operations

CAUSES: MINING ACTIVITIES

SOLUTIONS: SEASONAL FACTORS

• Install deep structural piles
• Implement gas and moisture barriers
• Create engineered ground stabilisation systems

CAUSES AND SOLUTIONS TO FOUNDATION DEFECTS - SETTLEMENT

CAUSES: COMPRESSION OF SUBSTRATA

• Consolidation of soft soils under building weight
• Decomposition of organic matter in soil
• Inadequate soil compaction during construction

• Use dynamic compaction techniques
• Install ground improvement methods
• Implement engineered fill materials
• Design flexible foundation systems

SOLUTIONS: LANDFILL ISSUES

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• Uneven settlement of poorly compacted fill material
• Decomposition of buried organic waste
• Chemical reactions in landfill causing soil instability

CAUSES: LANDFILL ISSUES

SOLUTIONS: COMPRESSION OF SUBSTRATA

• Install deep structural piles
• Implement gas and moisture barriers
• Create engineered ground stabilisation systems

Tree Related Problem

Figure 1. Minimum foundation depths for tree species/proximities (Chudley and Greeno, 2016)

• In areas with trees, their root which may reach down to 5 m are capable of desiccating soil.
• These can have effect on the building foundations: soil moisture depletion by tree roots, root growth causing soil upheaval, decay of old tree roots creating voids in soil.
• These can easily affect shallow foundations less than 3 metres deep, as against deep foundations with depths greater than 3 metres.
• Figure 1 shows the minimum foundation depths in shrinkable subsoils.
• Alternatively, use the free NHBC Foundation Depth Calculator on App Store, Google Play Store, or download the Windows OS version.

Causes of Foundation Defects - Settlement

Causes of Foundation Defects - Settlement �Tree Related Problem

Figure 1. Minimum foundation depths for tree species/proximities (Chudley and Greeno, 2016)

Solutions to Foundation Settlement Defects

Tree-related Problems:

• Conduct root zone investigations
• Implement root barrier systems
• Design foundations with increased structural resilience
• Remove problematic vegetation

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Figure 2. Root barriers (Shire, no date)

https://www.youtube.com/watch?v=trjTMDS1o2w

Video: Root Barrier

CAUSES: SULPHATE ATTACK

• Reaction between sulphates in soil and cement in concrete
• Common in areas with high sulphate content in groundwater
• Can cause expansion and deterioration of concrete
• Often seen in post-war properties with specific hardcore materials

• Use sulphate-resistant cement in construction
• Conduct soil tests to assess sulphate levels
• Implement protective coatings on concrete surfaces
• Design drainage systems to manage groundwater
• Regularly inspect and maintain concrete structures

SOLUTIONS: SULPHATE ATTACK

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Causes and Solutions to Foundation Defects

CAUSES: OVERLOADING

• Excessive weight beyond the foundation's design capacity
• Additions to the structure without proper reinforcement
• Changes in building use leading to increased loads
• Inadequate consideration of soil bearing capacity

• Conduct structural assessments before modifications
• Reinforce foundations as needed for additional loads
• Ensure accurate calculations of soil bearing capacity
• Monitor changes in building use and adjust accordingly
• Implement load distribution techniques in design

SOLUTIONS: OVERLOADING

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Causes and Solution to Foundation Defects

CAUSES: BAD DESIGN

• Insufficient depth of foundations
• Improper sizing of foundation elements
• Failure to account for soil conditions
• Inadequate reinforcement specifications

• Engage qualified structural engineers for design
• Ensure thorough site investigations are conducted
• Follow best practices for foundation depth and sizing
• Incorporate adequate reinforcement in designs
• Review and revise designs based on soil conditions

SOLUTIONS: BAD DESIGN

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Causes and Solutions to Foundation Defects

CAUSES: POOR CONSTRUCTION METHODS

• Use of substandard materials
• Improper concrete mixing or curing
• Inadequate compaction of soil or fill
• Failure to follow approved plans and specifications

• Use high-quality materials that meet standards
• Ensure proper mixing and curing of concrete
• Implement rigorous quality control measures on-site
• Train construction personnel on best practices
• Adhere strictly to approved plans and specifications

SOLUTIONS: POOR CONSTRUCTION METHODS

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Causes and Solutions to Foundation Defects

Group-assessment Task

Question 1

Considering the presence of a 5-metre-high poplar tree located five metres from the building, determine the minimum foundation depths that will mitigate the effects of soil shrinkage, ground heave, and other root-induced soil changes. 

Do you think it is practical to build the structure at this distance from the tree, if not, why?

Question 2

• How do foundation defects affect a building?
• Research the symptoms that a surveyor is likely to see that indicate the need for remedial works.

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Wall

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CAUSES AND SOLUTION TO WALL DEFECTS

CAUSES: BOWING/BULGING

• Excessive lateral pressure from soil or water
• Inadequate wall thickness for its height
• Deterioration of mortar joints
• Thermal expansion without proper expansion joints
• Foundation settlement causing wall distortion

• Install lateral restraint systems
• Use carbon fibre reinforcement techniques
• Implement helical wall ties
• Construct additional buttressing
• Apply structural reinforcement plates
• Undertake careful underpinning where necessary

SOLUTIONS: POOR CONSTRUCTION DETAILING

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• Inadequate or missing damp-proof courses
• Improper bonding between brick courses
• Lack of proper flashing around openings
• Inadequate provision for movement joints

CAUSES: POOR CONSTRUCTION DETAILING

SOLUTIONS: BOWING/BULGING

• Install comprehensive damp-proof courses
• Replace or repair existing wall ties
• Implement correct mortar joint techniques
• Ensure proper flashing around wall openings
• Use breathable waterproofing membranes

CAUSES AND SOLUTION TO WALL DEFECTS

CAUSES: WALL TIE FAILURE

• Corrosion of metal ties, especially in coastal areas
• Use of substandard materials for ties
• Insufficient embedment of ties in mortar joints
• Incorrect spacing or positioning of wall ties
• Overloading of ties due to cavity insulation

• Replace corroded wall ties with stainless steel alternatives
• Use chemical/resin-based wall tie replacement systems
• Implement mechanical wall tie reinforcement
• Conduct thorough corrosion assessment
• Install additional lateral restraint systems
• Use approved retrofit wall tie techniques

SOLUTIONS: LACK OF LATERAL SUPPORT

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• Removal of internal walls without proper consideration
• Inadequate tying to floor or roof structures
• Missing or inadequate buttressing
• Excessive unsupported wall heights

CAUSES: LACK OF LATERAL SUPPORT

SOLUTIONS: WALL TIE FAILURE

• Install additional structural support beams
• Use steel reinforcement straps
• Implement hidden wall ties
• Design appropriate load-bearing connections
• Use engineered structural interventions

CAUSES AND SOLUTIONS TO WALL DEFECTS

CAUSES: FAILURE OF SUPPORTING ELEMENTS

• Arches�• Loss of mortar in joints�• Inadequate abutment support�• Overloading beyond design capacity
• Lintels�• Corrosion of steel lintels�• Insufficient bearing at ends�• Thermal movement causing stress
• Joists�• Rot in timber joists�• Inadequate fire protection�• Overloading of floor structure

SOLUTIONS: FAILURE OF SUPPORTING ELEMENTS

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• Roof Timbers�• Woodworm or dry rot infestation�• Poor ventilation leading to decay�• Inadequate sizing for loads
• Expansion of Embedded Steel and Iron Fixings�• Rust jacking causing masonry cracks�• Corrosion due to moisture ingress�• Thermal expansion and contraction

• Arch Repair�• Carefully remove and replace damaged mortar�• Install additional support systems�• Apply structural reinforcement methods
• Lintel Repair�• Replace corroded steel lintels�• Install stainless steel or galvanised alternatives�• Use protective coatings
• Joist Repair�• Replace timber with treated or engineered materials�• Install damp-proof membranes�• Improve ventilation�• Apply fire-resistant treatments

• Treat for woodworm and rot�• Improve roof ventilation�• Replace damaged timbers�• Apply protective preservative treatments
• Embedded Metal Fixing Solutions�• Remove and replace corroded fixings�• Use stainless steel or non-corrosive alternatives�• Apply protective coatings�• Install moisture barriers�

CAUSES AND SOLUTIONS TO WALL DEFECTS

CAUSES: SURFACE FAILURE

SOLUTIONS: SURFACE FAILURE

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• Efflorescence�• Salt deposits from water movement�• Poor damp-proofing�• Use of cement-rich mortars
• Freeze-Thaw Damage�• Water absorption in porous materials�• Inadequate protection in cold climates�• Poor quality masonry units
• Sulphate Attack�• Chemical reaction with cement compounds�• Presence of sulphates in soil or groundwater�• Use of unsuitable mortar mixes

• Discolouration�• Biological growth (algae, lichens)�• Atmospheric pollution�• Leaching of minerals from masonry
• Cracking�• Thermal movement�• Settlement of foundations�• Structural overloading

• Efflorescence Treatment�• Improve damp-proofing�• Use breathable water-repellent treatments�• Remove salt deposits professionally�• Address underlying moisture issues
• Freeze-Thaw Protection�• Apply water-repellent treatments�• Use frost-resistant masonry units�• Improve drainage�• Install protective surface coatings
• Sulphate Attack Prevention�• Use sulphate-resistant cement�• Conduct thorough ground investigations�• Install chemical barriers�• Improve drainage systems�• Use specialist protective treatments

• Discolouration Remediation�• Professional cleaning techniques�• Apply protective surface treatments�• Remove biological growth�• Use breathable restoration materials
• Cracking Repair�• Install movement joints�• Use flexible pointing materials�• Address underlying structural issues�• Apply reinforcement techniques�• Monitor and manage structural movement

CAUSES AND SOLUTIONS TO WALL DEFECTS

CAUSES: Roof Thrust:

• Inadequate roof bracing allowing outward movement
• Deterioration of roof timbers causing spread
• Poor design of roof trusses or rafters
• Overloading of roof structure (e.g., from additional insulation)
• Insufficient tie at eaves level

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SOLUTIONS: Roof Thrust:

• Install additional roof bracing
• Implement collar ties/steel tension rods
• Reinforce roof structure
• Create additional lateral restraints
• Use engineered roof truss systems

Self-assessment Task

Investigate three historical buildings (in your area) and see the measures that have been used to prevent and control the wall movement.

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CHIMNEY

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CAUSES AND SOLUTIONS TO CHIMNEY DEFECTS

CAUSES: WEATHER-RELATED ISSUES

• Freeze-thaw cycles causing masonry damage
• Wind erosion of mortar joints
• Lightning strikes
• Heavy rainfall leading to water ingress

• Install protective weatherproof coatings
• Apply breathable water-repellent treatments
• Use frost-resistant pointing materials
• Install lightning protection systems
• Implement comprehensive drainage strategies

SOLUTIONS: STRUCTURAL PROBLEMS

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• Settlement of foundations
• Removal of supporting walls below
• Poor original construction techniques
• Inadequate support for heavy chimney pots

CAUSES: STRUCTURAL PROBLEMS

SOLUTIONS: WEATHER-RELATED ISSUES

• Undertake professional structural assessment
• Install additional support mechanisms
• Use helical wall ties and reinforcement
• Implement targeted underpinning techniques
• Replace damaged supporting structures

CAUSES AND SOLUTIONS TO CHIMNEY DEFECTS

CAUSES: WATER DAMAGE

• Defective or missing chimney flashing
• Cracked or damaged chimney crown
• Porous brickwork allowing moisture penetration
• Inadequate or damaged damp-proof course

• Replace or repair chimney flashing
• Install new lead or synthetic flashings
• Rebuild damaged chimney crown
• Apply specialist waterproofing membranes
• Implement comprehensive damp-proof courses

SOLUTIONS: WEAR AND TEAR

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• Age-related deterioration of materials
• Erosion of mortar joints over time
• Thermal expansion and contraction
• Sulphate attack on brickwork

CAUSES: WEAR AND TEAR

SOLUTIONS: WATER DAMAGE

• Conduct professional repointing
• Replace deteriorated brickwork
• Use specialist restoration techniques
• Apply protective surface treatments
• Implement regular maintenance programmes

CAUSES AND SOLUTIONS TO CHIMNEY DEFECTS

CAUSES: CREOSOTE BUILD-UP

• Accumulation of flammable deposits
• Inadequate cleaning and maintenance
• Use of unseasoned wood
• Poor burning practices

• Professional chimney sweeping
• Install chimney liner systems
• Use approved cleaning techniques
• Implement proper burning practices
• Install modern flue management systems

SOLUTIONS: FLUE LINING ISSUES

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• Cracking of clay tile liners
• Corrosion of metal liners
• Improper installation of liners
• Absence of required lining

CAUSES: FLUE LINING ISSUES

SOLUTIONS: CREOSOTE BUILD-UP

• Replace damaged clay or metal liners
• Install flexible stainless-steel liners
• Use ceramic or pumped concrete linings
• Implement comprehensive flue protection
• Conduct regular professional inspections

CAUSES AND SOLUTIONS TO CHIMNEY DEFECTS

CAUSES: EXTERNAL FACTORS

• Bird or animal nests causing blockages
• Tree damage from overhanging branches
• Poorly fitted TV aerials or satellite dishes
• Ivy or other climbing plants causing damage

• Install protective bird guards
• Remove damaging vegetation
• Relocate external fixtures
• Use specialist mesh protection systems
• Implement regular maintenance checks

SOLUTIONS: CHIMNEY CAP AND POT PROBLEMS

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• Missing or damaged chimney caps
• Loose or cracked chimney pots
• Deterioration of flaunching around pots
• Inadequate ventilation causing condensation

CAUSES: CHIMNEY CAP AND POT PROBLEMS

SOLUTIONS: EXTERNAL FACTORS

• Replace damaged chimney pots
• Install modern ventilated chimney caps
• Rebuild deteriorated flaunching
• Use specialist restoration techniques
• Implement comprehensive protection systems

Group-assessment Task

• Show/present the various parts of a chimney.
• Collect at least five photos of chimney defects.
• Discuss with your group the possible causes of each one.
• How do you think they can be repaired?

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Bibliography

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• Allcott Residential (2020) Birmingham and coventry building surveys: sulphate attack on concrete floors. Available at: https://www.allcottassociates.co.uk/blog/birmingham-survey_sulphate-attack/ (Accessed: 16 November 2024)
• Barry, P. (2011) Property Defects – Chimneys and Flues. Available at: https://www.peterbarry.co.uk/blog/property-defects-chimneys-and-flues/ (Accessed: 16 November 2024)
• Chimney Solutions (2024) Common chimney problems you should know. Available at: https://www.chimneysolutions.com/blog/common-chimney-problems-you-should-know/ (Accessed: 16 November 2024)
• Chimney Specialists Inc. (2024) 4 common causes of chimney damage. Available at: https://www.chimneyspecialistsinc.com/blog/chimney-damage/ (Accessed: 16 November 2024)
• Chudley, R. and Greeno, R. (2016) Building construction handbook. 11^th edn. London: Routledge.
• ECP (2024) What causes foundation failure?. Available at: https://www.earthcontactproducts.com/foundation-failure-causes/ / (Accessed: 16 November 2024)
• Pearson (2017) BTEC national construction student book. London: Pearson.
• Sandberg LLP (2024) Sulfate attack. Available at: https://www.sandberg.co.uk/laboratories/geomaterials/sulfate-attack/ (Accessed: 16 November 2024)
• Shire (no date) Root barriers. Available at: https://www.shire-uk.com/our-services/structural-repairs/root-barriers/ (Accessed: 16 November 2024)

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