BSEE O


Building owners are increasingly undertaking energyecient and sustainable retrofits of exisng properes as they oen aract higher rental rates or retain exisng tenants. Very oen, a refurbishment process can be undertaken in stages so that the operaon and tenancy of the building carries on, allowing rental revenues to connue during upgrades. For example, central building services could be upgraded at weekends to minimise downme and LED replacements carried out on a floor by floor basis out of hours


MAINTENANCE & REFURBISHMENT


The right balance  sustainable building refurbishment projects


verall refurbishment is usually a lower cost option than a new build and can also be more sustainable when considering the long-term environmental impact and a building’s whole life cycle. A sustainable refurbishment process could significantly reduce ongoing maintenance costs and limit the maintenance requirements, particularly if a building is listed or represents some architectural or historic interest. Also, modernising this type of space could attract clients as it has a unique market offering. The overall benefit for investors considering the refurbishment option is a quicker return, potentially on a lower capital spend when compared to a new development.


The other side of the coin


However, with refurbishment the levels of uncertainty and risk are much higher than for new build projects and these unknown elements can significantly impact both capital and programme related costs. As it is difficult to establish cost certainty, lump-sum contingencies are usually incorporated. This is often capital that could be allocated to sustainability initiatives but can’t be committed to at the required stages of a project. For example, modern energy and sustainability strategies focus on a passive first approach to reduce thermal and electrical demand. During refurbishment projects, the design elements that can influence the passive performance are often heavily constrained by the site location and existing structure. Likewise, state-of-the-art workspaces are based around guidance such as the WELL Building Standard which requires a change in thinking regarding how we interact with a space and how this will impact mental health and physical wellbeing. This requires early consideration of movement in the building and space planning that often doesn’t work in a refurbishment project as it is restricted by the existing layout. For example, it is possible that a more highly serviced environment is required than currently exists e.g. a naturally ventilated space needs to move to an air-conditioned space, which is often driven by modernised working practices that require more IT equipment and higher occupancy levels.


Such a situation would necessitate additional plant and equipment. However, existing plant spaces and risers, required to distribute ductwork and pipework, are often too small to accommodate new services, resulting in the useable/lettable floor space being reduced. Another unknown factor during a refurbishment programme is the likelihood of uncovering hazardous materials, such as asbestos, which increases costs as they must be dealt with in accordance with stringent health and safety procedures. Planning conditions can also be limiting and it can be difficult to work within the context of existing public realms and streetscapes. Consequently, the completed space might not meet a tenant’s vision in comparison to a new build, particularly in relation to the façade and links with the exterior.


Optimise returns


To optimise a refurbishment programme, first conduct a detailed-on site survey to determine the existing building strategies, the condition and age of equipment, and opportunities for introducing sustainability while taking into account restraints and buildability.


Through stakeholder consultation fully understand the client’s aims and, if possible, the tenant’s requirements by undertaking an occupancy evaluation survey to fully understand how people currently use the space. It is also important to understand any existing spatial and fabric constraints. For example, consider what elements of the façade will be retained and assess its existing fabric make-up and insulation levels. By conducting an air permeability test you can also determine the leakage rate. By using energy simulation software to undertake a series of desktop iterative studies the opportunities identified by the survey can be fully assessed. During this process, the whole life cycle impact of each initiative should be considered to inform the decision-making process within the given budget. Desktop simulation studies can also be used to assess the predicted internal environment conditions (temperature, daylight) to determine and drive improvements within the refurbished space.


uInterior of Marischal College


As government policies largely fall behind market factors in promoting energy efficiency, owners of existing properties often consider taking the voluntary certification route. For example, a study from the Building Services Research and Information Association (BSRIA) found that over 40 per cent of construction industry respondents recognised “return on investment” and “operational savings” as benefits of implementing BREEAM in the UK. BREEAM is the property industry’s recognised benchmark for the environmental rating of new and major refurbished buildings. It helps building developers, local authorities and building owners manage and mitigate risk through demonstrating sustainability performance during planning, design, construction, operation or refurbishment. This helps to lower running costs, maximise returns through the market value of a building, as well as attract and retain tenants by providing desirable places to live and work.


Refurbishment of Marischal College


uRefurbishment in stages allows the operaon and tenancy of the building to carry on


20 BUILDING SERVICES & ENVIRONMENTAL ENGINEER DECEMBER 2019


A positive example of a successful project is TÜV SÜD’s refurbishment of the iconic Marischal College, a large granite building that was constructed for the University of Aberdeen in 1835. Most of the building is now leased to Aberdeen City Council, which instigated a refurbishment project to create office accommodation for its new headquarters. TÜV SÜD used dynamic simulation software to model and test several energy reducing design options for the site. The design solution included a water source heat pump system for heating and cooling; low energy internal and external light fittings; low flow water fixtures; and an improved indoor environment quality due to increased outside air rates and thermal comfort optimisation. The extensive renovation was completed on schedule and significantly under budget, achieving a BREEAM ‘Excellent’ rating and an EPC Asset Rating of ‘B’.


www.tuv-sud.co.uk/real-estate Read the latest at: www.bsee.co.uk


uBREEAM is the property industry’s benchmark for the environmental rang of new and major refurbished buildings


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