Volume 13 (2024-25)

Each volume of Journal of Building Survey, Appraisal & Valuation consists of four 100-page issues in both print and online.

The articles published in Volume 13 are listed below.

Volume 13 Number 3

Editorial
Simon Beckett, Publisher
Case Study
From palisades to palace to party pad: Understanding and conserving 800 years of Fyvie Castle
Annie Robertson, Accredited Building Conservation Surveyor, Project Director, Fyvie Castle, National Trust for Scotland

Fyvie Castle is an A-listed building in the northeast of Scotland which is in the custodianship of the National Trust for Scotland and operated as a heritage attraction. Caring for our listed heritage buildings is an important task, one which is undertaken for the benefit of our nation and its people. This requires a conservation-led approach and a deep understanding of the site and application of conservation philosophy. The translation of philosophy into practice can, however, prove challenging and open to interpretation, particularly to the surveyor who is new to conservation. This paper explores the history and development of Fyvie Castle and demonstrates why obtaining this understanding is important in the considered response to key condition challenges. It also outlines the practical steps taken in the application of conservation philosophy to allow the development of a programme of major conservation works and considers the decisions to be made in the care of the castle.
Keywords: conservation; conservation philosophy; heritage; understanding significance; Scotland; castle
Practice Papers
Testing of property flood resilience: What have we learnt?
David Ramsbottom, Technical Director, Flood Management and Andrew Tagg, Technical Director, Flood resilience (retired), HR Wallingford, UK

Flood protection of properties has traditionally been provided by engineered flood defences. In recent years, however, there has been an increase in interest in flood protection for individual properties. This has taken two forms which together are referred to as property flood resilience (PFR): ‘resistance’, where flood water is prevented from entering a property, and ‘recoverability’, where flood water is allowed to enter a property but the damage is minimised in order to permit rapid recovery after a flood. Other methods for protecting properties including traditional flood defences are also discussed in order to provide an overview of the methods available and indicate where PFR fits in. The importance of PFR in flood management both in the UK and internationally is likely to grow as PFR is increasingly being considered as an important option to reduce flood risk for individual properties. Many different types of flood resistance products have been developed in order to keep flood water out of houses. Proof was needed that these products would be effective during a flood and the British Standards Institution (BSI) worked with HR Wallingford, the Environment Agency and product manufacturers to develop methods and standards for product testing. A product testing rig was constructed at HR Wallingford. Initially a large number of products were tested but the number has reduced as successful products have become established. In addition, some manufacturers have developed their own testing facilities. The tests have demonstrated that resistance products can protect properties provided that they are correctly installed, not overtopped by flood water, and water does not enter the properties by other routes. In addition, tests have been carried out to assess the performance of building materials under flood conditions both for flood resistance and flood recoverability. Flood product testing has evolved rapidly in recent years in the UK and other countries. This paper therefore does not claim to provide a comprehensive overview and includes some personal reflections and opinions based on the authors’ experience.
Keywords: flood protection; flood protection products; property flood resilience; flood resistance; flood recoverability; flood product testing
Insulating solid floors in listed buildings: Problems and opportunities
Sarah Woodger, Director of Operations, The Limecrete Company, Limecrete Products

This paper seeks to assist in the surveying of listed properties and the considerations that may be taken when addressing whether to insulate solid flooring and, if so, how to go about it. The author seeks to address a variety of potential problems and opportunities that may be found when assessing the property and does not consider this paper to cover all eventualities. One of the main things the author is aware of is the merit of each property needing to be assessed as a unique and individual entity. In many cases, it may also be worth looking at areas within the property itself; different rooms will have different needs, uses and potentially differing existing flooring and will therefore need to be addressed on a room-by-room basis. As the author runs a company that specialises in limecrete flooring, she is aware of her own potential bias and the weighted information that she will provide in her own specialist field. Therefore, this paper does not aim to suggest a single answer approach to the question of insulating solid floors in listed buildings; however, more detail will be given with regard to an insulated limecrete flooring approach. The author does not hold any design liability, and any design ideas described in this paper are based upon her knowledge and experience in the field. In particular, when it comes to limecrete floor design, she is drawing on designs that her company has been given by their customers to work on and the opportunities this has given for consideration in this paper.
Keywords: limecrete; floors; insulation; conservation; retrofit
Condensation risk analysis: A practical approach
Umendra Singh, Product Sustainability Lead, Soprema UK

The UK’s commitment to achieving net zero by 2050 stresses the necessity for highly energy-efficient building structures, emphasising a fabric-first approach. Inadequate design or execution can lead to unintended consequences, particularly condensation within the building envelope, posing risks of structural damage and mould growth. This paper delves into the intersection of precise design and a sustainable future, highlighting the crucial role of condensation risk analysis (CRA). CRA is vital for assessing moisture activity, predicting condensation and implementing measures to avoid or minimise associated risks. The study evaluates various moisture sources and mitigation strategies, focusing on rain ingress, construction moisture, rising damp, internal and external vapour pressure and moisture-laden warm internal air. Comparing two widely used CRA methods, the dewpoint method and hygrothermal numerical simulation (HNS), the paper emphasises their strengths and applications. Practical guidance on selecting the right CRA method based on project-specific scenarios, fabric types and moisture risks is provided. Case studies demonstrate the application of both methods in a conventional timber frame with a brick façade and internal wall insulation on solid brick masonry. Legal and regulatory considerations, including BS 5250:2021, are discussed, highlighting the importance of adherence to standards in effectively managing moisture-related challenges. The paper concludes by emphasising the significance of CRA in ensuring the longevity and efficiency of building envelopes, serving as a valuable resource for building surveying professionals.
Keywords: condensation; building envelope; dewpoint method; hygrothermal numerical simulation; moisture risk; fabric-first approach
Evaluating the durability of mortise-tenon joints in response to natural moisture weathering over time
Yueyao Wang and Regina Dufu Muller-Uri, University College London

When used in the appropriate context, timber structures might have lower embodied carbon than their concrete and steel counterparts, making timber a popular material for sustainable construction practices. To continue constructing with timber we require more in-depth exploration into timber joinery, which dictates the structural stability and performance of timber-framed construction. Moisture can affect the performance of timber joints. Rapid moisture changes over time can lead to joint failure, affecting the structure’s stability and safety. It is therefore important to understand how natural moisture weathering changes affect timber joints to ensure the longevity and safety of structures made from timber. This paper presents and discusses the results of a series of tests conducted by subjecting samples of timber joints to cyclically varying moisture conditions for several cycles and ultimately judging their effect on the performance of timber joints by measuring their rotational stiffness. The experiments select three commonly used timber joint reinforcement methods — traditional mortise and tenon joints, mortise and tenon dowel reinforcement and mortise and tenon glue reinforcement — to represent the majority of timber buildings in the UK. The results were compared to identify the advantages and disadvantages of the three reinforcement methods. The outcomes demonstrate that prolonged exposure to moisture can have a great impact on the performance of timber connections, resulting in decreased stiffness and strength. The use of reinforcement methods, however, such as mortise and tenon dowel reinforcement or mortise and tenon glue reinforcement, can mitigate the negative effects of moisture weathering changes on timber joints. This paper emphasises the importance of understanding moisture weathering changes and their impact on timber joints to ensure the longevity and safety of structures made from timber.
Keywords: timber; moisture; wetting and drying; humidity; rotational stiffness; traditional joinery construction
Inclusive environments: Access to commercial property, goods and services — disability-specific access requirements
Adrian Tagg, Associate Professor in Building Surveying, School of Construction Management and Engineering, University of Reading

It has been nearly 30 years since the introduction of the first bespoke legislation preventing discrimination against disabled people in accessing commercial property, goods and services. Despite the rise in public awareness of disability promoted by the Paralympics, a global financial crisis, austerity and the COVID-19 pandemic appear to have taken disability rights off both the political and social agendas. Research published in 2020 identified commercial value in providing a truly inclusive built environment and for commercial property owners as well as those delivering goods or services to seek opportunity over obligation in providing above-minimum access. In an attempt to challenge the notion of a ‘one size fits all’ approach to access, this paper analyses disability-specific access needs as well as unpick the term ‘reasonable adjustment’. The paper focuses primarily on the access to buildings and not the accessibility of actual service provision. The paper identifies that the complexity of disability, the wide-ranging symptoms of individual impairments and the prevalence of those with more than one condition validates a one-size approach to designing for disabled people. Furthermore, when comparing the delivery of best practice solutions to facilitate access, the paper demonstrates that the majority of the necessary adjustments are essential (critical) and not just reasonable. While this is based upon the experiential understanding of access challenges by disabled people, it is also worth noting that there exist significant challenges from a service provision perspective in proving an inclusive environment. Removing the existing physical barriers within the built environment may be difficult and costly, and may appear unreasonable for some smaller organisations. Despite this, however, there are a number of relatively low-cost, high-priority adjustments that can make a difference. These, along with more complex adjustments, mean it is necessary to adopt a balanced, pragmatic notion of compromise that facilitates access while still being commercially viable.
Keywords: disability; accessibility; built environment; reasonable adjustment

Volume 13 Number 2

Editorial
Simon Beckett, Publisher
Practice Papers
Reinforced autoclaved aerated concrete: The history and development of the product, its characteristics, uses and shortcomings
Trevor Rushton, Chartered Building Surveyor and Chairman, Watts Group

The media frenzy following the sudden closure of several schools in the summer of 2023 drew attention to the use of reinforced autoclaved aerated concrete (RAAC) in many public buildings in the UK, in turn spawning political debate as to why remedial action had not been taken sooner, whether chronic underinvestment was to blame, or whether successive governments had systematically cut corners by using cheap and short-life materials. Throughout this period the Royal Institution of Chartered Surveyors (RICS) and other professional institutions attempted to maintain a reasoned approach based upon factual analysis and developing knowledge as to the long-term performance of RAAC and the practical implications of its use. Despite poor experiences in the UK, RAAC has been, and still is, used extensively throughout Europe, the Americas and the Far East seemingly without the litany of failures identified in this country. This paper attempts to explain the history and development of the product, its characteristics, uses and shortcomings. Comment will be given on survey methodology, risk assessment and remedial works along with potential legal implications for surveyors and other practitioners.
Keywords: RAAC; AAC; Aircrete; aerated cellular concrete; deflection
Asbestos and the skills gap
Nicky Honing, Senior Account Manager, Astutis

The asbestos sector is unique within the built environment. The history of asbestos extends well beyond the 100 years that we are commonly aware of. It is known to be one of the most devastating workplace killers, with figures released by the Health and Safety Executive (HSE) demonstrating a current trend of approximately 5,000 deaths annually attributed to diseases caused by exposure to asbestos fibres. This paper looks at the highly specialised job roles that the industry struggles to attract fresh talent into. It summarises some of the statistics and make observations as to how asbestos continues to be a prevailing hazard affecting management, maintenance and modernisation of aging buildings across the UK. The aim is to continue to help educate the built environment sector about a unique culture of highly specialised persons that float between and around the realms of inspection, testing, certification, occupational hygiene, health and safety, and construction and demolition. The paper comments on the position of the industry in the current economic climate and proposes a change of attitude and understanding to progress and ensure the risk to human health posed by asbestos continues to be reduced and quality of service delivery improved.
Keywords: asbestos; training; asbestos removal; asbestos consultancy; asbestos management; quality
Water damage restoration, structural drying and remediation of damp issues in UK properties: A comprehensive review
Alan James, UK Sales Director – Portable Solutions, Group Key Account Manager – Water Damage Restoration, Dantherm Group

Water damage is a pervasive issue in the UK, with adverse effects on property structures and indoor air quality. This paper provides a comprehensive review of water damage restoration, structural drying and remediation techniques tailored to UK properties. It discusses the causes of water damage, including flooding, leaks and dampness, and explores the principles and methods of effective restoration and remediation. Special attention is given to the unique challenges and considerations faced by property owners, contractors and restoration professionals in the UK context.
Keywords: water damage; structural drying; damp issues; remediation; UK properties; restoration
Transforming homes, transforming lives: The role of property logbooks in scaling retrofit
Rachael Owens, Co-Director, National Retrofit Hub

The pace of good quality retrofit must be urgently scaled up across the UK, in order to tackle fuel poverty, improve the health and comfort of our homes, increase energy security and build climate resilience. Currently, however, incomplete information is used when designing retrofit policies and plans. There are barriers to the scale-up of good quality retrofit including citizen engagement, finance, supply chain uncertainty, a lack of trust and low uptake of quality assurance frameworks. This paper discusses the potential of enhanced, interoperable and democratised building, local and systems data to unlock many of these barriers. It will explore how the adoption of property logbooks across the UK can enable the aggregation of projects and drive access to finance. A retrofit plan for every home has the potential to engage and empower citizens and small to medium enterprise (SME) builders to act locally. This paper describes how the right packages of data can inform better decisions, what work has already been done to date, and how you can get involved in creating transformational change.
Keywords: retrofit; data; logbook; energy efficiency; health; well-being; fuel poverty
Research Paper
A multi-life cycle assessment of external wall insulation strategies in an Irish domestic retrofit
Sara Carrigan, Architect, School of Architecture Building & Environment, Patrick Daly, Lecturer and Researcher and Alberta Congeduti, Lecturer and Environmental Consultant, School of Architecture Building & Environment, Technological University Dublin

European Union (EU) policy and initiatives are driving both building renovation and the uptake of low-embodied carbon and circular design in the construction sector. The European Performance of Buildings Directive (EPBD) recast (2021) introduces global warming potential (GWP) methodology, and the future state will likely be embodied carbon targets for which life cycle assessment (LCA) of buildings will be required. External wall insulation (EWI) will have an important role to play in meeting targets. In this context, this paper compares the carbon emission payoff of three alternative EWI strategies that address conventional, low-carbon and circular solutions to EWI respectively, in the retrofit of an existing dwelling. The circular strategy is based on design for disassembly (DfD). Whereas standard LCA is based on a single building life cycle, the literature reviewed shows that the environmental impact assessment of DfD requires a multi-life cycle approach. In the absence of standardised methods for assessment, four multi-cycle LCA methods are selected and applied holistically in a case study investigation. Three allocation methods, 100:0, linear degressive (LD) and enhanced linear degressive (CELD), provide a range of emissions from ‘conservative’ to ‘best case’ over three building life cycles and the fourth method, the Van Gulck method, assesses the benefits of circularity through the concept of ‘multi-cycling’ based on one building life cycle. As each method of assessment will deliver different results, carbon emission payoff is not a fixed value. Findings show that with multiple use, the circular strategy pays off due to avoided production emissions and benefits from end-of-life (EoL) processes that DfD facilitates, that the upfront carbon cost of the circular strategy is minor relative to the carbon emission savings that reuse brings, and that the margin of improvement relative to the alternative strategies increases with each subsequent reuse.
Keywords: EPBD; LCA; multi-cycle LCA; circular economy; circularity; design for disassembly (DfD); embodied carbon; external wall insulation (EWI)

Volume 13 Number 1

Editorial
Simon Beckett, Publisher
Practice Papers
An investigation into the vapour permeability and durability of natural renders on an earthen wall system
Jim Carfrae, Plymouth University, et al.

This paper describes a novel methodology for establishing the relative moisture performance of renders used to protect a novel walling system combining traditional dense cob with a low-density thermal cob. A new method of enhancing the thermal insulation of cob walls has been developed by an European Union (EU)-funded joint UK and French project called CobBauge. The external surface of traditional cob walls (comprising subsoil, fibre and water) is normally protected from driving rain by placing the walls on a short wall called a plinth, a pronounced eaves overhang and a breathable exterior render. As the low-density fibre and clay insulating layer in the CobBauge system differs from traditional cob, a method of establishing the moisture-related performance of a range of renders needed to be instituted to aid the materials selection process. A series of test panels were constructed with the thermal cob infill, faced by a number of render types. The panels were hung in an open position in a high exposure zone and the moisture content monitored using wood-block sensors, electrical resistivity and gravimetric measurements over a period of six months. The wood-block and electrical resistivity moisture measurements showed a good level of agreement with gravimetric measurements and showed a clear differentiation between the various render choices.
Keywords: earth walling; cob; render; lime; moisture
The Access to Neighbouring Land Act 1992: A useful tool or a blunt one?
James Brenan, Spencer West

This paper explains what the Access to Neighbouring Land Act 1992 does and how it fits into the legal landscape of issues for developers and property owners to be mindful over. It draws from case law learning and from the practical experience of the writer in dealing with site access, crane oversailing licences and Part 8 claims. Its aim is to give prospective parties to access licences and those advising them a full insight into the issues that arise, a warning as to the costs of litigation and the confidence to start negotiating within sensible limits.
Keywords: access; neighbouring land; trespass; damages; injunctions
Invasive invaders: Japanese knotweed and non-native species in our homes
Daniel Docking, Property Care Association

This paper dives into the intriguing discussions of Japanese knotweed and other invasive non-native plants, how they affect our built environment, and the legal ramifications for allowing these plants to spread beyond the realms of confinement. The paper sheds light on historical misinformation and begin to establish a nuanced understanding towards a plant which is surrounded in hysteria. In an attempt to unravel the cause of this hysteria, the paper describes a well-known plant which is five times more likely to causes structural issues to a property. The paper also highlights the presence of another plant which has striking similarities to Japanese knotweed; however, the paper advises caution in avoiding exacerbating even more unnecessary hysteria. The paper highlights building professionals’ potential ignorance of other invasive species beyond Japanese knotweed and the impacts they could cause. The paper aims to equip readers with insights into legal complexities, debunk myths surrounding invasive non-native plants but bring to light new emerging threats. It advocates for a comprehensive risk assessment approach, fostering a nuanced understanding of the impacts of various invasive species.
Keywords: Japanese knotweed; buddleia; bamboo; giant hogweed; structural damage; property surveying
How to play nicely: The current law of party wall surveyors’ duties, and what to do with it
Richard Webber, RLS Law

This paper aims to set out the current state of the law on the duties and responsibilities of party wall surveyors, in the context of historic and recent case law, with a particular focus on Welter v McKeeve (2018) and Walsh v PSB Management & others (2022), and based on that to give the reader a practical guide to dealing with the difficulties of being instructed by one party but having duties to that party jointly with others. It identifies a trend in case law on party wall surveyors’ duties of having particular regard to the rights and interests of the adjoining owner and notes a potential inconsistency with the client-facing duties owed by party wall surveyors appointed by building owners. It discusses the extent to which, and manner in which, party wall surveyors should include their appointing owners in their investigation and decision-making process. It concludes that these might best be resolved by acting as impartially as possible commensurate with the surveyor’s duties to their appointing owner, keeping the parties reasonably informed, but at all times retaining control over the decision-making process. The law is stated as at February 2024.
Keywords: party wall surveyors; duties; duties to appointing owner; duty of impartiality
Impact protection using novel fibre reinforced concrete
Alan Richardson, Michelle Littlemore, Northumbria University and Harry Toase, Balfour Beatty Vinci HS2

The research described in this paper identifies how the use of three-dimensional (3D) unwelded fibre reinforcement can provide protection against back-face spalling in the case of damage caused by impact, and contributes to understanding how such material specification can carry significant long-term benefits. When subjected to ballistic impact or explosion, reinforced concrete suffers back-face spalling caused by compressive stress waves, resulting in projectiles that can cause injury and collateral damage. This conceptual study seeks to reduce concrete projectiles and subsequent damage using 3D unwelded fibre-reinforcement. Conventional two-dimensional (2D) straight fibres rely on orientation and positioning for effective bridging of rupture planes, whereas 3D fibres benefit from inherent superiority of their orientation across a rupture plane. Twenty-five kilograms of 3D unwelded fibres (3DUWBL) and 2D fibres per m3 of concrete were used in the mix designs. Samples were tested for compressive strength, fibre pull-out, three-point and four-point flexural testing and ballistic impact. There was significant improvement in toughness and post-fracture control within the 3DUWBL specimens. The 3DUWBL fibres exceeded EN 14889 standards, outperforming the 2D fibre specimens, and controlled back-face spalling and reduced airborne projectiles in comparison to the 2D fibres. The study is limited to demonstrating proof of concept. The implication of these results will inform future research studies in this area. The results identify a current gap in research associated with 3D unwelded fibre use and the reduction of back-face spalling. 3D fibres overcome the significant failings of even dispersion and bond pull-out strength ordinarily associated with 2D fibres. This is due to the x y z orientation and omission of the welded connection. The implications are a reduction in manufacturing time and costs, making 3DUWBL fibres a more viable industry application. This research shows that 3D unwelded fibre reinforcement provides good resistance to back-face spalling of concrete elements when they are subjected to ballistic stresses. Such fibres are not currently commercially available, but they would be cheaper to produce, and their novel fibre shape provides enhanced post-crack toughness performance with the addition of lower variability, providing a lower-risk form of crack control.
Keywords: impact; ballistic; toughness; fibres; concrete
Professional indemnity insurance for architects: Not so ‘professional’ after all?
Anthony Le, Smooth Commercial Law

This paper provides an insight that opens up systemic flaws with regulatory bodies and a considerable blind spot in professional indemnity insurance. This is an eye-opening analysis of an industry that is closely tied to building surveyors, structural engineers, valuers, architects and — by extension — lawyers.
Keywords: architects; professional indemnity insurance; Professional Consultants Certificate; insurance; professional negligence; negligent misstatement; defective premises; litigation
Research Paper
Hygrothermal risk assessment of external wall insulation (EWI) retrofit to non-traditional wall types in an Irish context, using the Glaser method and a heat, air and moisture transient model
Gareth Mc Donnell, O’Shaughnessy & Associates and Joseph Little, Technological University Dublin

The Climate Action Plan 2019 targets the low-energy retrofit of 500,000 existing Irish homes before 2030.1 Up to 80 per cent of building failures can be attributed to moisture risks.2 The literature indicated that external wall insulation (EWI, ETICS) failures are mostly due to moisture ingress at junctions and interfaces. A hygrothermal risk assessment of EWI on three walls with rendered concrete/concrete blockwork/cavity walls in Dublin, Belfast and Belmullet was undertaken using transient numerical simulation and the Glaser method. The guidance, common practice indicates a preference for Glaser. The initial simulation results were compared to assess the appropriateness of Glaser. Material measurements were undertaken and this data was used in the transient numerical simulations. A parametric study was undertaken using a selection of the initial transient numerical simulations stressed with parameters of 1–2 per cent driving rain at different window positions. The results of the initial transient numerical simulations indicate that most retrofit cases, except on cavity walls, are low risk. All cases assessed using Glaser pass the assessments. The parametric study indicated between 40–67 per cent were high risk depending on the wall types. All cases with mineral wool/mineral render were low risk, while most cases with acrylic render were high risk. The research described in this paper indicates that using the Glaser method for hygrothermal assessment of EWI cannot capture the extent of the risk when buildings are leaking.
Keywords: hygrothermal risk assessment; EWI; ETICS; failure
Book Review
Termites and heritage buildings: A study in integrated pest management
Reviewed by Dr Jagjit Singh, Environmental Building Solutions