From Steve McSorley, Director, Perega
The concept of circular design in construction is nothing new and, over the last decade, many articles have been written on the long-term advantages this approach can offer society at large.
One particular aspect of this admirable ethos I’d like to address in this article is the repurposing and renovation of industrial and commercial properties for residential use. I feel it presents a huge opportunity for housebuilders across the UK to increase their stock sustainably and simultaneously offer quality housing.
Reimagining derelict sites and bringing them back to life has numerous benefits. From the outset all-important building structure is already there, often in a good state of repair, so efficiencies already exist from the start. Not only do you have these foundations and but, usually, access to core infrastructure including lines to utilities, road links to retail and other essential services such as schools and hospitals.
I should caveat before we go further, each site, depending on its location, will have its own unique advantages and challenges which will need to be considered.
Let’s take location as one example. Brownfield sites in close proximity to town centres, of which there are many across the country, will benefit from better access to transport and employment opportunities. Repurposing in rural/semi-rural areas will require the creation of specific infrastructure to accompany it. This comes at a cost and, as such, might prove a less attractive proposition, especially for affordable housing projects.
This is just one of many factors which need to be considered. As such it’s essential to do adequate research and groundwork before you commit. So, for those developers looking to seize the opportunity to repurpose a former commercial or industrial building for residential purposes I’ve highlighted a number of specifics which need to be considered.
The art of the possible
The first is feasibility. We recently worked on a site in Hemel Hempstead where, rather than investigating the whole building, we targeted specific areas. We brought in specialists to assist as we conducted our surveys and scrutinised the appropriateness of the build.
This initial, phased approach will reveal whether we should go forward or abandon the project. It’s a more efficient and cost effective method than approaching the whole structure and means you can proceed knowing the financial risk is lower as the expenditure gets higher.
Drain on resources
Another factor we regularly encounter is ensuring surface water and foul drainage has been considered and that flooding on- and off-site has been eliminated through robust design.
Brownfield sites create unique challenges. Often there is existing infrastructure to consider; there is often made ground and contamination on site that heavily influences how surface water can be disposed of, and space is often very limited as brownfield sites tend to be in built up areas.
Nevertheless, current guidance and policy demands that brownfield sites are regarded to be the same as a greenfield sites, which is that the design storm (1 in 100 year + 40% for climate change) must be sufficiently attenuated and discharged slowly, preferably on site, but may need to be discharged off-site at a rate of no more than two litres per second per hectare.
This can often be a challenge on brownfield sites, but it is best achieved by working closely with the regulators, understanding the local environmental and hydro-geological constraints and understanding local and national policies.
Where possible, this is achieved through the use of surface level sustainable drainage systems (SuDS) such as ponds and rainwater gardens. These provide multiple benefits, such as pollution mitigation, habitat creation and amenity benefits and the use of SuDS should be considered first by developers on brownfield sites when there is scope to incorporate them.
It is also important to consider the capacity of the foul water network. A change from commercial or industrial units to residential accommodation will place higher demands on the public sewer system. It is important to consult early with the local water authority through their pre-planning enquiry system to ascertain whether there is capacity in the local foul sewers and whether a development has a right to connect. There may often be a requirement to upgrade the local public sewer system as part of the residential development connection process and it is imperative that this is determined at an early stage in a development and agreed with the water authority.
To achieve all of the above, it is essential to carry out the required surveys, consultation and design work long before planning submissions and preferably even before any site layouts have been generated by the architect or the developer. This ensures the smoothest path towards success at the determination stage and that the development has ‘made space for water’.
Minimising the risk
Being aware of changing building codes and standards is also important, each project needs to be approached on a case by case basis.
For instance, when working on a particularly old building, does fire resistance meet new regulations? These codes and standards encompass a myriad of different requirements, including means of escape and other issues such as loading and disproportionate collapse, particularly if new storeys are to be added on the existing structure.
It’s about mitigating risk as much as possible, and a high level of detailed investigation needs to be carried out to ensure compliance with Regulations. If I was to stress one point, this would be it. Failure to comply with the regulations poses a significant risk to both construction workers and end user safety.
Safe as houses?
It’s no secret the UK is crying out for quality housing. Former commercial and industrial buildings present a potential, cost effective solution, so long as developers approach such projects in a cautious, responsible and regulation compliant way.
In the past, when governments commit to ambitious targets to tight deadlines, there has been a tendency towards a ‘dash for trash’ with disastrous consequences.
Approaching any project which seeks to repurpose for residential use needs to be complemented by detailed, investigation, surveying work and feasibility studies to ensure it’s safe and appropriate.
Housebuilders have the capability and vision to lead from the front, reimagining redundant structures giving them a new lease of life to serve a useful, essential purpose.