The forgotten voids of the Palace of Westminster

Last month I went on exploratory walks with the team of surveyors and staff of the Palace of Westminster Restoration and Renewal Programme team. The aim was to explore some of the forgotten voids inside the Houses of Parliament that had once formed part of the original, now disused, nineteenth-century ventilation system. Many of these spaces are hidden between floors or within the depth of thick walls that are also difficult to access. In one instance we had to open hatches under leather benches in order to get access to spaces under the floor of the Royal Gallery, and on another occasion it was necessary to crawl through a small hole to reach the Victoria supply channels of the House of Lords debating chamber.

Why does the Palace have so many hidden voids?

The first system, introduced in the 1850s, was a central air system. The entire volume of air required for the ventilation of the Palace of Westminster was supplied and extracted centrally through tall shafts and towers. The internal voids were needed to get the fresh air from the inlet shafts to the individual rooms across the Palace and also to take hot air from these rooms to a series central air outlets. Most of the fresh air was admitted through shafts inside the Victoria Tower and distributed through an extensive network of air mains inside the basement.

To achieve this Charles Barry’s team had to accommodate large internal spaces for handling the air, taking over spaces that had previously been allocated to other uses. More space was needed for cooling, humidifying or heating the supply air. In the House of Lords and the main ceremonial spaces connected to it, the fresh air was collected and conditioned in air chambers below the principal floor. These were linked through vertical shafts and flues to the basement, galleries or ceilings.

The chambers vary in scale. Some are shallow voids measuring less than a meter in height, while others extended over two full storeys. In some spaces we had to crawl, in others stand with our knees bend, but many are tall enough to stand. It is also to be highlighted that the Victorian ‘ductwork’ was composed of heavy stonework, forming an integral part of the physical fabric of the building. Air chambers were hidden within the depth of floors and vertical and horizontal air flues were built in brick or were carved into masonry walls.

A new survey.
These voids have not been systematically surveyed before. Knowledge of the design, position or original function of historic air shafts and chambers has been lost. The plans held by the Parliamentary Estate Directorate, which are based on surveys undertaken by the Office of Works between the 1880s and 1950s, do not cover these voids. The surveyors Plowmancrawen are employed to undertake the first ever comprehensive survey of the Palace’s existing fabric using modern 3-D laser scanning technology that is referred to as ‘point cloud scanning’.  It will yield data for the production of a virtual model on the computer that the consultants involved in the refurbishment will be able to use in the design. Already in the 1850s complaints were made about the lack of drawings giving a comprehensive picture of the ventilation arrangements. A first attempt at a detailed survey of the ventilation arrangements as built was made in the 1860s under the direction of the Palace’s resident engineer John Percy. This lack of comprehensive plans was largely due to the fact that some solutions were agreed orally on site and that information about different aspects of the ventilation arrangements was scattered across numerous sketches, drawings or written specification without being consolidated. To gain a full understanding of the original ventilation arrangements, which is the aim of my research, it is therefore necessary to consolidate information scattered over several thousands documents, including original sketches, drawings, letters and written specifications from the mid-nineteenth century. My research project thereby plays an important role in guiding the survey.

My role in the new survey is to introduce the surveyors to different voids and explain their original function within the original ventilation system. Their original function is not known to current staff and over the past three years I have produced papers and given presentations for staff of the Parliamentary Estate Directorate and Restoration and Renewal Programme, introducing them to the design of the historic ventilation arrangements. The surveys, however, will also provide new insights into the historic ventilation system. It illuminates aspects that were not documented or that deviated from the arrangement shown in the archival records.

The walk undertaken this month was only the beginning of a much longer inquiry into the historic fabric of the Palace and how it had been shaped by requirements of ventilation. The current focus is on the Victorian ventilation of the Lords end of the Palace, including the Royal Gallery, Prince’s Chamber, Queen’s Robing Room and the debating chamber itself.

I am currently working on a detailed reconstruction of the Lords’ system and how it had changed over time. This research is based on the study of archival material and site visits. Over the next few weeks I will spend a lot of time studying the surviving physical features of the historic system. This will involve producing sketches and photographic surveys. The buildings itself provides an important source of physical evidence, which together with the archival research and the surveyor’s 3-D scans, will yield critical new insight into the lost Victorian system


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