Sustainability is generally accepted as being the movement towards energy efficiency, use of renewable energy sources and recycling.  In broad terms this means buildings need to minimise both the amount of energy used to operate and the amount of waste produced.

Given the high cost of energy and waste removal, this is a good idea from an economic standpoint, irrespective of ecological issues. So, becoming sustainable is one of those win – win situations, saving the planet and money!

If only things were that simple. Looking purely at the energy issues, a fully sustainable building would be described as carbon neutral, ie: the net energy used by the building is zero.  In order to achieve this, a building needs to capture energy from the environment to offset that used from the grid.

Whilst this is technically possible, especially on new buildings, applying this idea to existing properties is very difficult. Consider the average small office block in an average town centre. It is probably surrounded by other properties on three sides, fronts directly onto a main street and has a mix of occupiers.  It was probably built in the late 1960’s and although maintained, it could now do with a full refurbishment.

The question is, how could a property such as this be made sustainable? The biggest cost of running any building relates to maintaining a stable temperature. To do this the building must first be protected from temperature variations outside as far as possible.  To do this, the walls, floor and roof will need to receive additional insulation, the glazing will likewise need replacing with more thermally efficient units and draughts will need to be eliminated.  The effect of these changes will be to minimise the amount of energy needed to heat or cool the building.

The next stage will involve the replacement of heating and cooling plant with more efficient units.  This is the point where the building can start to extract energy from the surrounding environment.  Modern air conditioning systems are actually heat pumps which can move energy from one place to another. So, in the winter energy is taken from outside the building and put inside, and in summer the reverse occurs. When heating, these systems are often able to transfer three times the energy they use into the building: ie; for every 1kW used by the system, 3kW is transferred into the building.

Whilst these systems are efficient,  power is still used to run them.  Also, when cooling, the system has to remove heat gained from the environment (sun etc) plus remove the energy produced by people and office equipment.

The building must therefore generate power to run the air-conditioning plant.  The choices available for power generation from renewable sources are limited, especially within a town centre. Given our scenario, wind turbines are unlikely to work due to the shading effects of nearby structures. Also, to generate the power required, either the building would become festooned with turbines (1 small turbine for every 6 square metres) or one very large unit would need to be installed. Clearly neither option is viable.

The alternative is photovoltaic cells converting sunlight directly into electricity. The problem with this solution, and putting the weather aside, is that the roof of the property is simply too small to install sufficient cells to generate the amount of power required.

So, is becoming sustainable impossible?

On an individual building basis, this is true, however all buildings need to lower their energy requirements to enable the gap between the amount of non-carbon dioxide generating power produced, and the country’s energy requirements to be closed as far as possible.

Whether this is enough of a driver to persuade landlords and tenants to contribute to the costs of the works required is questionable. What may persuade landlords is recent evidence that energy efficient buildings are beginning to attract higher rents. While the percentage uplifts are small at present, this effect is bound to grow as energy costs increase and tenants seek lower operating costs.

To the wonder and amazement of other people I must be one of the few Building Surveyors that admires and appreciates the styling, design and material choice of the modernist architecture of the 1960s. However as a building surveyor such buildings are also a challenge as there’s usually a wide variety of defects with both building materials and construction technologies. Every so often along comes an absolute shocker.

The building in question was a typical 1960’s concrete shopping centre with the usual flat roofs, raised walkways and underpasses. Over the years it had been changed around so many times it had been left with unusable space and adhoc shaped units. A number of the shops were empty and the whole shopping centre was pretty run down.

A multitude of defects were evident everywhere you looked, with the main concern being spalling concrete and corroded reinforcement with suspicions this was caused by the carbonation of the concrete. Putting aside the immediate Health and Safety issue represented by one particular loose section of concrete which could have quite easily dislodged and fallen onto a passerby causing serious harm if not death resulting in an area being cordoned off, an urgent remediation plan was clearly necessary.

Carbonation occurs when carbon dioxide in the atmosphere reacts and decomposes the hydrated products of the cement in concrete to form various carbonate minerals, the layer of concrete affected being known as the ‘carbonated layer’. If the steel reinforcement is within the carbonated layer the protection offered by the high alkalinity of the concrete is diminished allowing water and oxygen to penetrate the concrete and react with the steel causing it to corrode. As part of the corrosion process the steel expands resulting in the concrete spalling, thereby exposing the steel reinforcement to further deterioration which in time will lead to structural failure.

Immediate repairs to the concrete was clearly essential and this followed the process of identifying all loose areas of concrete, hacking this off to expose the steel reinforcement bars, grit blasting to remove corrosion, applying a proprietary primer to the surface of the reinforcement and finally undertaking concrete patch repairs using a cementitious material and sand, and a polymer dispersion. A long term solution to inhibit further carbonation would be to restrict the entry of carbon dioxide by applying a coating to the concrete which would act as a protective barrier.

Along with this work other defects, including water ingress and damp problems generally, were rectified and the development was given a lick of paint and new shop fronts providing the centre with the opportunity for another lease of life.

Toby Ware Bsc (Hons) MRICS

Toby Ware has just recently joined Naylors Chartered Surveyors after working at rival property consultants, Lambert Smith Hampton, for four years. The holder of a first class honours degree in Building Surveying from the University of Northumbria, Toby achieved RICS chartered status in 2006.

Toby is a valued addition to Naylors’ expanding Building Consultancy Department. His experience extends across the commercial, professional and contractual sides of building surveying and he has worked on a number of industrial, office, government, licensed and retail buildings for both public and private sector clients.

“Although there is already an established Development and Consultancy division at Naylors Chartered Surveyors, this is an exciting opportunity for me as I will heading up the development of new business outside of the firm’s existing Property Management portfolio and the Department as a whole has the skills and resources to be able to provide clients with strategic and technical property advice for any given circumstance.”  Said Toby.

Director of Consultancy Angus White welcomed Toby to the Practice. “With the cost of building occupancy being one of the biggest items in any businesses’ expenditure, in these difficult times pro-active property management and building advice is essential in saving costs” he said. “Toby has the ability and enthusiasm to take this side of our business forward in the years to come and we are very pleased that he has agreed to join us.”