Alan Mark Forster

Maintenance for historic buildings: A current perspective

Purpose – It is well understood that maintenance is critical to the survival and in‐service use of any building. Despite recognition that the best way of protecting and maintaining historic buildings is to undertake a combination of proactive and reactive maintenance, it is rarely adopted or implemented, and when it is undertaken it often results in varying degrees of success. Maintenance theory currently exists, but fails to be realised in practical application and implementation. It is the purpose of this paper to ask why this failure is occurring.Design/methodology/approach – The paper is composed of a critical review of existing literature, highlighting some of the major issues affecting maintenance implementation. It also reports the early stages of proposed research ongoing at Heriot‐Watt University.Findings – Despite recognition in the literature of the need to maintain historic buildings, this review suggests that the ways in which maintenance is organised and financed often mitigates against its ...

Building conservation philosophy for masonry repair: Part 1 - "ethics"

Purpose – The techniques available for the repair of historic masonry structures are extremely wide ranging. The advantages and disadvantages of each type of repair can be evaluated in terms of cost, time and quality as with modern projects. It is however, important to realise that when repairs to historic buildings are selected they must conform to building conservation philosophy, or an ethical and principle based evaluation. This paper (part 1 of 2) aims to establish what is meant by ethics in this context and wherever possible seeks to apply practical examples to these concepts.Design/methodology/approach – The paper takes the form of an evaluative literature review of the ethics encapsulated within building conservation philosophy utilising them to stimulate discussion on practical repair interventions.Findings – It is shown that ethical considerations are of prime importance for decisions relating to masonry repairs. These repairs have varying degrees of defensibility, and will ultimately lead to go...

Building conservation philosophy for masonry repair: part 2 – “principles”

Purpose – The techniques available for the repair of historic masonry structures are extremely wide ranging. The advantages and disadvantages of each type of repair can be evaluated in terms of cost, time and quality as with modern projects. It is however, important to realise that when repairs to historic buildings are selected they must conform to building conservation philosophy, or an ethical and principle based evaluation. The purpose of this paper (part 2 of 2) is to establish what is meant by principles in this context and wherever possible apply practical examples to illustrate these concepts.Design/methodology/approach – Evaluative literature review of the principles encapsulated within building conservation philosophy utilising them to stimulate discussion on practical repair interventions.Findings – It has been shown that the principles of building conservation philosophy must be considered prior to making decisions relating to masonry repair. These repairs have varying degrees of defensibility...

“Plastic” repair of natural stone in Scotland: perceptions and practice

Purpose – The purpose of this paper is to address the issue of perceptions of suitability of different materials for a repair. The use of highly cementitious materials in the repair of historic masonry is causing great concern due to their incompatibility with adjacent stone and the associated accelerated deterioration which results from their use. The relatively recent development of so‐called “restoration mortars” based on a “mix and go” application, combined with the enhanced weathering of stone in a changing climate, may be contributing to the use of “plastic” repair materials on stone across Scotland.Design/methodology/approach – Following a literature review, case studies of repairs are presented to highlight the advantages and disadvantages of using such materials, and comparisons are made with the alternative options.Findings – The case studies presented highlight the use of a number of different stone repair materials, sometimes in combination with stone replacement, representing functional and p...

Specialist ‘restoration mortars’ for stone elements: a comparison of the physical properties of two stone repair materials

BackgroundThe perceived increasing use of ‘restoration mortars’ for the conservation of historic masonry is often viewed as controversial due to the long-standing contention associated with ‘plastic’ repairs in the heritage sector. Almost innumerable traditionally built sandstone structures exist worldwide and the wide scale use of restoration mortars for their repair is evident on a national and international level. Use of largely incompatible, impermeable and/or highly cementitious materials in the past is the cause of many problems, particularly associated with moisture entrapment. These issues, that continue several decades after a material’s use, raise the question of whether similar problems are likely to arise in the future due to the use of restoration mortars.ResultsThe chemical and physical characteristics of two restoration mortars are determined by laboratory testing. This work revealed significant differences in the physical properties of two restoration mortar materials, but also between these and the physical properties of two natural sandstones. Material characterisation reveals differences between the composition of the binders and aggregates in the two restoration mortars tested. Significant differences in their strength and water diffusion properties were noted.ConclusionsThe results provide an indication of material performance and a platform for objective decision-making on the suitability and specification of these materials. This work is of particular importance in the heritage sector, but its applicability is not limited to historic buildings. Comparison of the materials properties presented in this paper with the characteristics of representative sandstone substrates can give an indication of material compatibility. This research is aimed at stimulating further testing into the interactions of these materials within the context of historic masonry substrates.

Traditional cob wall: response to flooding

Purpose – The influence of flood conditions upon traditional cob construction is little understood. This paper aims to investigate the ability of cob materials to resist flood situations and documents basic failure mechanisms. This work also seeks to investigate the wettability characteristics of cob materials utilising environmental scanning electron microscopy.Design/methodology/approach – This paper takes the form of a literature review and case study underpinning laboratory experiments.Findings – Cob walls that are suitably compacted, straw reinforced and are composed and manufactured of the correct materials appear to have the ability to resist total failure when subjected to initial flood conditions, however, the duration to which these structures will remain intact has still to be ascertained, and testing is ongoing. A correlation appears to exist between the rate of cob materials compaction and the duration to which the structural integrity of the walls was retained when the samples were submerge...

A framework for specifying natural hydraulic lime mortars for masonry construction

Purpose – The selection of lime mortars for masonry structures can be an important component of a repair or new build project. This selection is considered difficult due to the number of variables to consider during the decision‐making process and the perceived inherent complexity of the materials. The purpose of this paper is to discuss the selection process for determining suitable natural hydraulic lime repair mortars for masonry.Design/methodology/approach – The paper presents a conceptual and practical framework for the determination of suitable lime mortars for repair and construction of masonry structures, drawing and building on relevant, literature and existing best practice guidance on specification.Findings – The use of various relatively newly produced data sets pertaining to durability can aid in the appropriate selection of lime mortars. These determinants must however, be correlated with traditional evaluation of exposure levels, building detailing and moisture handling performance. Buildin...

Green Maintenance for historic masonry buildings: an option appraisal approach

Purpose – Sustainability is well understood to encapsulate economic, environmental and societal parameters. The efficiency of maintenance interventions for historic buildings is no exception and also conforms to these broad factors. Recently, environmental considerations for masonry repair have become increasingly important and this work supports this growing area. The purpose of this paper is to give insight on how an option appraisal approach of “Green Maintenance” modelling for historic masonry buildings repair practically determine and ultimately substantiate the decision-making process using a calculation procedures of life cycle assessment, within delineated boundaries. Design/methodology/approach – Calculation procedures of the model enables an assessment of embodied carbon that is expended from different stone masonry wall repair techniques and scenarios for historic masonry buildings during the maintenance phase. Findings – It recognises the importance roles Green Maintenance model can play in re...

Hunt the shadow not the substance: the rise of the career academic in construction education

Construction education is context-laden, navigating and reflecting the byzantine influences of period, place and person. Despite considerable rhetoric, in UK higher education and construction studies in particular the importance of contextualized teaching is being devalued. Over the past decade a growing number of new teaching staff to university lecturing has limited or no industrial experience of the construction sector. This paper explores the rise of the career academic in construction education and implications for teaching standards and student learning. Whilst career academics exhibit research skills and afford funding possibilities that universities find appealing, pedagogical studies suggest that experience-led, contextualized teaching offer students enhanced educational value. Policy-making and pedagogical strategies that continue to value research at the expense of teaching excellence coupled with recruitment of career academics as opposed to industry professionals present new challenges for construction education, teaching and student learning.

Binder loss in traditional mass masonry: A cause for concern?

Purpose – The purpose of this research is to highlight issues relating to binder migration in traditional lime mortars and the potential consequences of this phenomenon. The paper focuses on traditional mass masonry construction and will be of special interest to those surveying, maintaining and repairing historic ruinous structures and heavily exposed masonry bridges.Design/methodology/approach – The paper draws on literature pertaining to the repair of traditional mass masonry structures and the somewhat limited science of binder dissolution and migration in saturated conditions. The paper also draws on the authors practical and academic knowledge of writing specifications for the repair of mass masonry structures and utilises examples of binder migration from several case study buildings.Findings – The degree to which binder migration in traditional mortars occurs is little understood. It is, however, evident that migration of the binder occurs when saturated conditions are present and is exacerbated ...