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The purpose of this paper is to improve the understanding of the impact of mass timber construction methods on construction performance through the successful delivery of the first-of-a-kind tall wood building, Brock Commons Tallwood House (Tallwood House). This paper is one of a set of papers examining the project; companion papers describe innovations used during the mass timber design and construction processes.

A mixed-method, longitudinal case study approach was used in this research project to investigate and document the Tallwood House project. Quantitative data were collected to perform the following analysis: hook time, the variability of productivity and schedule reliability. Members of the research team observed construction progress, meetings and decision-making, conducted periodic interviews and reviewed project artifacts.

The research presented in this paper is the culmination of a longitudinal study aimed at studying the innovation process on a project where radical innovations of structural systems were developed. Prefabrication, combined with the use of a virtual design and construction (VDC) model for planning and fabrication and early collaboration with trades, construction managers and consultants, increased the labor productivity of the on-site erection of the mass timber structural components and envelope panels and expedited the construction schedule.

This paper details an in-depth investigation into the construction productivity for a unique building project and lessons learned. The case study chosen is the construction of Tallwood House at the University of British Columbia. Tallwood House was the tallest mass-timber hybrid building in the world at the time of its construction.

Millions of properties have suspended timber ground floors globally, with around ten million in the UK alone. However, it is unknown what the floor void conditions are, nor the effect of insulating such floors. Upgrading floors changes the void conditions, which might increase or decrease moisture build-up and mould and fungal growth. The purpose of this paper is to provide a review of the current global evidence and present the results of in situ monitoring of 15 UK floor voids.

An extensive literature review on the moisture behaviour in both uninsulated and insulated suspended timber crawl spaces is supplemented with primary data of a monitoring campaign during different periods between 2012 and 2015. Air temperature and relative humidity sensors were placed in different floor void locations. Where possible, crawl spaces were visually inspected.

Comparison of void conditions to mould growth thresholds highlights that a large number of monitored floor voids might exceed the critical ranges for mould growth, leading to potential occupant health impacts if mould spores transfer into living spaces above. A direct comparison could not be made between insulated and uninsulated floors in the sample due to non-random sampling and because the insulated floors included historically damp floors. The study also highlighted that long-term monitoring over all seasons and high-resolution monitoring and inspection are required; conditions in one location are not representative of conditions in other locations.

This study presents the largest UK sample of monitored floors, evaluated using a review of current evidence and comparison with literature thresholds.

The purpose of this paper is to review the historic development of the requirements for sub-floor (also known as “basementless space” or “crawl space”) moisture management in the USA, UK and New Zealand (NZ) from 1600s to 1969.

The review of 171 documents, including legislation, research papers, books and magazines, identified three time periods where the focus differed: 1849, removal of impure air; 1850–1929, the use of ground cover and thorough ventilation; and 1930–1969, the development of standards.

Published moisture management guidance has been found from 1683, but until the 1920s, it was based on the provision of “adequate” ventilation and, in the UK, the use of impermeable ground cover. Specific ventilation area calculations have been available from 1898 in the UK, 1922 in the USA and 1924 in NZ. These are based on the area of ventilation per unit floor area, area of ventilation per unit length of perimeter wall, or a combination of both. However, it was not until 1937 in the USA, 1944 in NZ and after the period covered by this paper in the UK, that numerical values were enforced in codes. Vents requirements started at 1 in. of vent per square foot of floor area (0.7 per cent but first published in the USA with a misplaced decimal point as 7 per cent). The average vent area was 0.69 per cent in USA for 19 cases, 0.54 per cent in NZ for 7 cases and 0.13 per cent in UK for 3 cases. The lower UK vent area requirements were probably due to the use of ground covers such as asphalt or concrete in 1854, compared with in 1908 in NZ and in 1947 in USA. The use of roll ground cover (e.g. plastic film) was first promoted in 1949 in USA and 1960 in NZ.

Common themes found in the evolution of sub-floor moisture management include a lack of documented research until the 1940s, a lack of climate or site-based requirements and different paths to code requirements in the three countries. Unlike many building code requirements, a lack of sub-floor moisture management seldom leads to catastrophic failure and consequent political pressure for immediate change. From the first published use of performance-based “adequate” ventilation to the first numerical or “deemed to satisfy” solutions, it took 240 years. The lessons from this process may provide guidance on improving modern building codes.

This is the first time such an evaluation has been undertaken for the three countries.

Points to the decline of “craftsmanship” as a factor leading to the demise of the ability to control timber decay in an environmentally‐friendly fashion. Considers pesticides and other chemical‐based treatments as a lower‐cost, relatively recent, but often unsuccessful remedy to timber decay. Outlines major timber‐decay problems: dry rot, wet rot and woodboring insects, and their detection techniques. Includes diagrams and detailed discussion on remedial treatments. Concludes that timber decay cannot be effectively treated without an understanding of the interaction of the external environment, building materials, design and content, and the activities within and occupants of a building, and that manipulation of a single variable (timber decay organisms) is bound to be unsuccessful without such understanding.

Since the time of primitive man, timber has remained the most useful and versatile of all naturally available materials. Its obvious aesthetic value makes it irreplaceable in the manufacture of fine musical instruments, furniture and great works of sculpture, but its greatest use is in the construction of our dwellings. Whether used in its almost natural state to construct a forester's log cabin, or sliced up into convenient pieces to build most of the world's homes, it is unsurpassed for versatility, ease of working and mechanical strength.

In order to establish sustainable development, there is a need to focus on solutions effectively improving environmental performance. Effectiveness is the product of significance and improvement potential. For buildings, the supporting structure is the predominant environmental load by materials, hence significant. The purpose of the studies presented in this paper is to determine the improvement potential of the supporting structure of buildings and explore other sustainable solutions effectively enhancing environmental performance.

For the same office layout, various combinations of structural components at different spans were studied. The environmental load of these variants was determined by means of an life cycle analysis (LCA)‐based model.

The studies presented in the paper demonstrated an environmental difference by a factor of 5 between the solutions performing worst and best. The optimal combination is the uncommon solution of TT‐slabs with timber beams and columns, expecting to establish an improvement factor of 4 with respect to common practice.

The findings of the studies presented suggest another way of building, with common structural components but whose combination is not common at present.

So far, sustainable building has not focused enough on effective solutions and has had little means to do so. Approaching the supporting structure of buildings rather than small, ineffective adaptations will significantly improve environmental building performance. An elaborate LCA of supporting structures had never been done before. The paper, on the one hand, rationalises sustainable building and, on the other hand, supports effective sustainable design.

Suspended timber floors are probably the most common form of construction for ground floors in existing British housing, although they exist in only a small proportion of newly built houses. If moisture builds up in the crawl space beneath the floor, wet or dry rot may begin, leading to structural damage to the floor and foul smells entering the living areas. The crawl space is ventilated by air bricks to prevent this happening, but this is often inadequate, and many houses suffer from damp conditions in the crawl space which are potentially harmful. These can be alleviated by increasing the ventilation, but the increased flow of cool outside air beneath the floor leads to higher heat losses in winter. Examines the relationship between crawl space ventilation rate and relative humidity.

Continues the investigation into the development of ground floors in residential buildings. Focuses on the constructional features of traditional ground floors, both solid and suspended. Describes the influences that constructional form had on the development of ground floors. Indicates that suspended timber ground floors became more common after the mid‐nineteenth century.

Explores the development of ground floors in residential buildings. Highlights the lack of detailed studies into this aspect of construction technology. Suggests that a multidisciplinary approach is needed to clarify the chronology and form of ground floors in old buildings. Considers the various types and traces their evolution. Indicates that suspended timber ground floors became more common after the mid‐nineteenth century.

Practical conservation of heritage buildings in Kolkata started in the 1990s and the first restoration project was the Town Hall, a public building built by the British in 1813, in the central business district by a public‐private partnership. The purpose of this paper is to demonstrate the restoration process and adaptive reuse of the Town Hall as a case study.

A team of conservationists, architects and structural engineers worked during 1996‐1998. The methodology included surveying and documenting the existing structure; examining old materials and methods of construction, earlier repairs and the suitability of matching new materials; analysing the structure, defects and their causes; prescribing remedial measures; preparing items of work, estimating and tendering for appointment of contractors; allocating funds for restoration; supervision and monitoring of the works.

It was necessary to undertake structural strengthening and physical restoration through corrective measures, and reinstallation of all service systems, which resulted in the opening up of this edifice again for various kinds of public use, that included a museum.

This was a pilot project for the state administration and the people of Kolkata. After this project, the conservation of historic buildings became an agenda of government and civil society. The lessons learned here were applied to the restoration of other similar buildings in Kolkata.

Conservation‐researchers, academics and practitioners will gain from this paper an in‐depth understanding of the restoration process in Kolkata.