From Specifile

The general applicability of the comparative superior thermal performance claims made by various lightweight walled Alternative Building System providers, that assume their walling systems’ higher insulation values [R-values], relative to double skin clay brick walling, translate into superior thermal performance outcomes, is not supported by science and extensive thermal modelling of houses constructed with different wall types here in South Africa.

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For South Africa’s climates, thermal modelling studies, supported by extensive empirical research in Australia, validate that while the R-value is a useful measure of thermal resistance of the wall itself, a walling material's R‑value is not representative of the thermal value for energy efficient house design properties of a material.

Notably, the research confirms thermal mass [naturally inherent in clay brick], as a critical thermal performance property for optimising thermal performance outcomes in South Africa's climate, where well defined average diurnal temperature swings characterise all six major climatic zones. It is the ability of thermal mass to slowly absorb, store and release heat, in ways that insulated lightweight walling cannot, that make clay bricks valuable in optimising thermal comfort inside houses.

As to be expected, the thermal modelling studies of both 130 m² and 40 m² low cost house types here in South Africa, that are consistent with the findings of 7 years of empirical research undertaken at the Priority Research Centre for Energy at the University of Newcastle in Australia, reinforce the validity of the latest WSP Energy Africa CR Product research, that if homes of the future are to achieve energy reduction targets, external walls must contain reasonable levels of thermal capacity, supplemented by varying levels of thermal resistance depending on the climatic zone. Clay brick brings both properties to the table most cost effectively. Lightweight walls can only bring resistance, and resistance on its own led to sub-optimal thermal performance outcomes for heating and cooling internal spaces in all the studies.

Adding further to this Dr Alec Johannsen of Alec Johannsen Consulting Engineering, in his review of the WSP Energy Africa CR Product study, noted: "There is an additional advantage of heavier walls (not discussed in the CR Product report as it is outside its scope), namely a reduction of the building peak cooling and heating loads."

Low Cost House Building Materials and Discomfort Hours in South Africa"This is the combined result of a reduction in the peak heat gain of the wall itself, and a time lag of the peak heat flux on the inside of the wall in relation to the heat flux on the outside, which makes the heat load from the wall out of phase with the other heat loads, resulting in a lower combined peak total heat load."

"The result is a smaller and less expensive cooling and heating plant and a lower electrical demand. The above would indicate that greater 'Cs' (thermal capacity) should be favoured over 'Rs' (resistance) when selecting a required CR Product."

South Africa’s benchmark construction methodology provides for optimal thermal outcomes, and cost effectively too. That face brick incurs no future carbon debt adds further environmental value to clay brick walling and drives lowest Life Cycle Costs.

Corobrik’s economic face bricks were used to build Khayelitsha’s first double storey unit currently being used for a crèche, after investigations by the South African Homeless People’s Federation found Corobrik to be the most sustainable, durable and economical product for affordable homes.

Seen at the Arthur Educare Centre in Khayelitsha is Corobrik’s Annette Richards (second from left), pictured with members of the South African Homeless People’s Federation.

“This was a rewarding experience for us having dealt directly with most residents. Many of them, though in their 50s had never lived in a formal house before.  Initially people were impatient to have their houses built and opted to use concrete blocks because they thought it would get their homes built faster. But they regretted this decision when they saw the disadvantages associated with concrete blocks. These houses built of concrete experienced dampness, cracking and relied on paint to become visually pleasing though they were brand new. Some waited a long while before the new houses were eventually painted and did not anticipate that the houses had to be repainted year after year to maintain its aesthetic appeal,” says Marthinus Williams, Internal Sales Planner for Corobrik Cape Town.

Williams says that when the Homeless Peoples Federation of South Africa noticed the poor quality of the new houses they began investigating alternate solutions to provide formal housing to the people of Khayelitsha. While budget was a key factor the federation was looking for a strong, sturdy product that could withstand inclement weather.  Equally important was a product that required no maintenance over time. Fire disasters in such rural areas are common; therefore the fire resistant nature of Corobrik’s clay face bricks was an impressive quality for the federation.  Thermal efficiency was yet another significant necessity. Keeping warm during the cold winter months with no electricity is a reality for most residents so the bricks had to be thermally amenable. According to Williams the high thermal mass of Corobrik’s clay bricks work particularly well in winter.

 

“Our clay bricks absorb and stores the heat from the winter sun and this heat energy is slowly released as the cool night air enters internal spaces, helping to moderate the temperature of internal spaces and naturally delaying the cooling of the walling envelope.  Houses built using double-skin clay brick construction, incorporating ceilings with insulation and adequate roof overhangs present the most cost-effective, durable and sustainable solution for the development of low cost housing on a national scale. For this project, Corobrik satisfied the necessary requirements and proved economically viable too,” says Williams.

 

Director of the Homeless People’s Federation, Patricia Matolengwe says that Corobrik has exceeded all their expectations.

 

“Ever since we began discussions with Corobrik we have received outstanding service. The advice and encouragement from staff at Corobrik have assisted us with tough decisions that would not have been possible without their expertise. Representing people from poor backgrounds, our main concern was the cost. While the municipality subsidised part of the cost, it is up to residents to settle the remaining expenses.  We know Corobrik’s reputation as market leaders and were afraid that affordability would be a problem. After just one meeting with Corobrik we realised that our fears were unfounded,” says Matolengwe.

 

According to Matolengwe they were given a competitive proposal which included Corobrik’s Dappled Rustic, Meadow Travertine Variation, Cape Blend seconds and reject face bricks. Corobrik’s proposal was immediately accepted for subsidising by the local government. To date one hundred and ten 40 m² and 72 m² houses have been built and the aesthetic appeal of the face bricks is obvious.

“These bricks will never need maintenance so the people won’t have to worry about expenses relating to painting/ plastering in future.  Also, the bricks are strong so residents can sleep at night knowing that rain will not seep into or damage their new homes in any manner. Corobrik’s quality and service is outstanding but most impressive has been their contribution to the lives of the poor,” says Matolengwe.

Marthinus concludes, “Corobrik has the distribution reach to deliver, the superior quality to adequately shelter and the service excellence to maintain affordable housing not only in the Cape but across the country too. Corobrik is ready to meet South Africa’s housing challenge.”

This analysis by colleague Dr Johan Snyman reviews the lending criteria of Banks and the consequent influence on the property market. The results are enlightening and will probably not be a surprise.It pursues a question that was repeatedly posed at our recent Strategic Forums - did we experience a property bubble and was it influenced and funded by debt?

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There is general agreement that we did not remotely experience a property bubble in South Africa, although other Countries did (notably the USA, UK and Ireland). The reasons for this can be found beyond ordinary mortgages in the arena of securitization (of sub-prime mortgages), derivatives, Credit Default Swaps (CDS's) and Credit Default Obligations (CDO'S) - basically driven by greed (see Michael Lewis' book: The Big Short: 2010).

There is also agreement that Home Ownership is funded by Mortgages which are traditionally classified as debt - therefore the continuous harping on Household Indebtedness and Disposable Household Income (with mortgages the main scapegoat because it comprises some 60% of total indebtedness).

The research confirms our contention that the Banks hold an inordinate amount of power and influence over the fortunes of the building and property industry. They play in every quadrant of the Stakeholder matrix and they make the rules of the game that all other Stakeholders must play to. All the debate about household indebtedness is used as justification for the strict lending criteria. The easy target to lower the indebtedness is to curtail mortgage advances, to make it increasingly difficult for households to purchase a home. And this is the strategy followed by Banks everywhere. And
this of course fundamentally impacts the property market and the building industry.

The home is the single biggest investment made by households in their lifetime - and also the best way for ordinary households to build wealth. The only serious money most people will make in their lifetime is on the capital appreciation of their homes. People have to live somewhere and it is extremely rare for individual households to have sufficient savings to purchase a home without a mortgage.

Even the current required deposit of between 10% and 20% is beyond the means of the majority of households. But it is common cause that households expect and are willing to pay (even
sacrificially) up to 30% of the household income for the privilege of owning their own homes and not to be obligated to a Landlord. The argument that it is better to rent than to buy is fallacious because it ignores the fact that there isn't sufficient rental stock and buy-to-let investments are subject
to even stricter lending criteria and has basically ground to a halt.

It also ignores the fact that Home Ownership is an investment (not a debt like a motorcar) and the repayments are really a forced saving. In theory if everyone became renters then household debt will be reduced substantially and will be limited to the very lucrative debts (for the Banks) of motor
vehicles and credit cards. And the world will be very much the poorer for it.

The fact is that the Building Industry will not recover until the Banks relax their strict lending criteria - or alternative Investment models are found.

See the presentation by the writer to the July Strategic Forum on The Art of
Quantum Planning applied to the Building Industry - posted on our website
under Quarterly Reports.

Dr.Llewellyn B Lewis