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Building Regulations – Sustainability vs Architecture

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Building Regulations – Sustainability vs Architecture

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8 min read

Basic overview of the building regulations. The government introduced its energy efficiency regulations for new buildings in November 2011.

The aim was to bring down the energy consumption of buildings so as to reduce pressure on the national grid and reduce carbon emissions, and as a general contribution to environmental sustainability. The regulation, known as SANS 10400 XA, covers hot-water heating efficiency, the efficiency of the building envelope, and services like lighting that utilise energy. These regulations apply to all new buildings, and there are some differences in detail depending on where the building is situated. There are six climatic zones in South Africa based on the climate characteristics of the area.

Water heating

The regulations require that half the hot water used in a building must be heated by efficient methods like solar heating or heat pumps. All hot-water pipes must be clad in a suitable insulating material with a specified R-value (thermal resistance) relative to the pipe diameter. All hot-water supply pipes must be connected in a ring main format that forms a continuous loop to and from the geyser. This reduces the time it takes for the water to get hot when you turn on a tap, thereby reducing water and energy wastage.

Building envelope

The building envelope requirements cover the elements that make up a building, and the orientation of buildings relative to the direction of the sun.


In order to reduce the need for heaters in the winter and air conditioning in the summer, the main living areas should be carefully designed to face north, so as to maximise sun in winter, and should be fitted with good overhangs to prevent the higher altitude summer sun from reaching the windows. The exact orientation and size of overhang can be worked out from readily available tables and software. Obviously, some rooms will have to face south, but these should be rooms that are not used often, like spare rooms, storage rooms and even bathrooms.


If underfloor heating is used, the regulations require an insulating layer with a R-value of not less than 1. It is advisable to use insulation regardless of whether underfloor heating is to be installed or not, as a lot of heat can be lost through the floor and into the ground below. This insulation is usually in the form of rigid polystyrene boards laid on the ground before the concrete floor is cast.


The composition of the external walls of a building must achieve a minimum R-value appropriate to the climatic zone in which the building is situated. The R-values of all elements are added together to get a total R-value. For example a typical double-skin brick wall will combine the R-value of the internal plaster, each row of brickwork and the external plaster. Currently this type of wall construction meets the minimum requirements inland, but there is talk that the soon-to-be-released revised regulations may require inland buildings to have cavity walls as standard, as is required at the coast. If one decides to use an unconventional building method, like timber frame construction, then the R-value of each component of the wall needs to be calculated from outside to inside and added up to achieve the required efficiency.

Windows (fenestration)

The regulations require that the size of windows relative to the floor area of rooms be such as to minimise loss of heat during winter, and to prevent excessive sun in the rooms in summer. Once again the performance figures required are based on the six climatic zones. The basic principle is that the bigger your windows are relative to the floor area, the more difficult it is to conform. It may be necessary to use double glazing and more efficient frame options to avoid heat loss, and/or shading mechanisms to reduce heat gain.

Roof assemblies

One of the biggest contributors to heat loss and heat loading in a building, along with windows, is the roof. The regulations once again refer to the different climatic zones, and the slightly different performance figures required for each zone.

All elements that make up the roof, including the ceiling, roof covering and even air gaps, have their relevant R-values added together to achieve a certain performance figure as required in the regulations. These basic components of the roof are insufficient to achieve the required figures, so the bulk of the requirement has to be made up of some form of roof insulation. The insulation ranges from your typical fibre blankets or blow-in loose fill fibre to rigid polystyrene boards. The requirements are a lot more stringent than the typical 50 mm thick fibre blankets (aerolite) that we have all used for the past 50 years. In order for the insulation to be effective, it needs to be about 130 mm thick.

This is not limited to the typical pitched roof construction with tiles or sheeting, but also affects flat concrete roofs. Even though a concrete roof seems quite thick and dense, its insulation properties are not that good, so insulation is usually required – either under the slab as a ceiling, or on top of the slab and then covered with the screed. This insulation is usually in the form of rigid polystyrene boards, but there are other products like concrete additives and lightweight insulated screeds that can be utilised.


There is a maximum energy consumption allowance for lighting in buildings. In a typical house the allowance is an energy demand of 5 watts/m2 (basically if all the lights are switched on at the same time) and an annual energy consumption of 5 kWh/m2 (the annual energy usage based on the average hours per day the lights would be switched on if they were all on at the same time).

In simple terms, the old incandescent and halogen bulbs that we are used to are no longer viable due to their high energy consumption. LED and CFL bulbs are the only types that comply with the requirements.

Challenges to architects

Implementing the new regulations was a steep learning curve for most architectural professionals. The mindset had to move very rapidly from decades-old accepted inefficient building practices to a new awareness of the minimum standards required by the amended legislation. Although challenging at the time, this has also proved beneficial, because it has forced many professionals to be more conscious of what they are designing. So, rather than designing something just to look “nice”, one is now forced to implement functional design principles that have been around since the dawn of architecture, when buildings were designed to be functional elements in harmony with their environment, rather than just objects of beauty or status symbols.

Architects often have to educate their clients, most of whom are not familiar with the regulations. It can be difficult to explain to a client that the regulations require certain non-aesthetic but costly building solutions, and that some luxury design items may have to be sacrificed in order to comply. It is all about changing the mindset of the public in general and the client in particular, and embracing the new legislation as a valuable resource. And although there may be additional costs upfront in the building process, energy efficiencies will recover those costs over time.

The new regulations have also slightly increased production time and the architectural professional’s workload, as detailed calculations have to be made of hot-water consumption, building orientation, window efficiency and lighting energy consumption. This requires more detailed drawings at the council submission stage of the project.

Many contractors and subcontractors are not as familiar with the building regulations as they should be. It can be challenging to tell them that the way they have been building is wrong, and to persuade them to follow the drawings and specifications explicitly. For example, very few plumbers know how to install a hot-water system with a ring main system. Even though these regulations have been around for decades, they have never been properly enforced by the local authorities, so many installations have been done incorrectly and inefficiently. This means that while many are willing to try to comply, the new regulations do increase the possibility of errors. I was recently in a house where the water from the hot tap would run hot for about five seconds and then go cold – because the hot-water system was not going through the geyser and was feeding direct from the cold water supply, syphoning off a little hot water along the way.

Ultimately, the responsibility of enforcing the regulations lies with the architectural professional.

Cost implications of the legislation

The legislation has affected building costs, but not exorbitantly. An obvious example is the window regulations for houses in areas like Camps Bay, where large picture windows are popular to take advantage of the views. This may require large areas of double glazing, which is at least double the price of single glazing. Heat pumps and solar systems are expensive, and LED light bulbs are much more expensive than the old-fashioned incandescent bulbs. However, one must offset these costs against the energy saving in the long run. For example, a heat pump is 70% more efficient than a geyser element, LEDs use about 80% less energy than incandescent bulbs, and insulation and thermally efficient windows reduce heating and cooling costs. Taking these factors into account, the long-term savings are substantial.

Creative solutions and software to assist with cost management

The calculations required to maximise thermal, light and water efficiency are very complicated, so most architects use software specifically designed to calculate the most efficient way of conforming to the regulations, or even – as I usually recommend to my clients – going beyond them in energy and water saving. For example, I recently completed a residence that required only single glazing, but I was fortunate enough to have a client who appreciated the principles of energy saving. We used double glazing throughout the residence, and installed underfloor insulation and natural ventilation mechanisms, as well as the standard required heat pumps and roof insulations, and even a grey-water and rain-harvesting system. The result is that when one enters the house, its constant temperate and comfortable environment, regardless of the outside conditions, is immediately noticeable.

Building legislation vs aesthetic guidelines

These two aspects go hand in hand, without a doubt. The building regulations are there for a reason, and have been formulated and revised over many years to ensure that buildings are structurally sound and efficient, but they do not specify any aesthetic standards. These are the responsibility of the developers, the homeowners’ association and/or the estate management. But there is obviously an overlap, as certain regulations may affect the aesthetics of the building. An example is the requirement for solar water heating or heat pumps, which are not very attractive items. Solar panels must be placed to face the sun, and heat pumps can look quite unsightly, much like air-conditioning units. With these items now being a requirement, one has to accommodate and conceal them in an aesthetically pleasing manner – something that needs to be set out in the form of aesthetic guidelines.

The value of aesthetic guidelines

Architecture is probably the most visually dominant aspect of people’s everyday lives, and it affects us on conscious and subconscious levels. We live, work and play in buildings, but – sadly – some buildings are less pleasing to inhabit than others. It is therefore important to control the aesthetic of an estate by providing guidance and encouraging responsible and visually pleasing design. This is even more important on a residential estate, because estate living creates an expectation of a certain lifestyle. For this reason, reputable developers consult architectural professionals before starting construction, in order to establish an aesthetic standard.

About the author

John McKenzie established the practice of John McKenzie Architecture in 2006, and focused predominantly on the residential market, striving to create unique and exclusive designs that achieve a harmonious union between client, site and environment. Over the years the practice has broadened the scope of the projects it undertakes to include motor dealerships, high-density living and retirement villages, in order to achieve a more diverse exposure in the industry. John also serves as the architectural consultant for the upmarket Saddlebrook Estate in Kyalami, Johannesburg

Prior to establishing his own practice, John gained a wealth of experience in the fields of residential, commercial, hospitality and industrial architecture, working for various renowned architects on projects as diverse as the smallest of house alterations to multimillion-dollar hotel resorts in Dubai.

John is constantly exploring energy efficiency in design. With the increasing burdens on our natural resources, national grid and water supply, there is a definite need for a stronger focus on energy-efficient architecture. The more awareness there is of this need, the more accessible and affordable these technologies will become.

John McKenzie Architecture provides a full architectural service from design conception to project administration, with selected service agreements available, tailored to suit each client’s requirements.

Designing with passion, innovation and value.

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