Alternative building technologies for low-income housing in cape town

Introduction

The 2019 project report by a team from Worcester Polytechnic Institute (WPI) focuses on evaluating the use of Alternative Building Technologies (ABTs) to improve low-income housing in Cape Town, South Africa. The research was conducted in collaboration with the City of Cape Town’s Department of Human Settlements (DHS) to support more cost-effective, durable, and environmentally friendly housing solutions.

South Africa’s historical legacy of apartheid left a housing system plagued with inequality, and despite government initiatives like Breaking New Ground (BNG), hundreds of thousands remain on housing waitlists. The study’s goal was to explore how ABTs can help overcome the challenges of traditional brick-and-mortar housing while addressing residents’ concerns and perceptions.

Project Objectives

The WPI team set out with five core objectives:

1. Evaluate safety and construction quality in selected BNG housing developments.

2. Analyze the cost-effectiveness of ABTs versus traditional methods.

3. Assess resident satisfaction and identify recurring issues in BNG housing.

4. Understand public perceptions and barriers to ABT acceptance.

5. Recommend suitable ABTs for future DHS projects.

Background: The Challenge of Low-Income Housing in Cape Town

The BNG housing program, launched in 2004 as a successor to the RDP (Reconstruction and Development Program), aims to provide free housing to low-income South Africans. However, the need vastly outweighs supply — with over 350,000 households on the housing registry in Cape Town alone.

Although BNG housing has improved conditions for many, widespread complaints about structural defects, overcrowding, poor ventilation, and lack of safety features persist. Public preference for brick and mortar homes remains strong, while alternative construction methods are met with skepticism and resistance, perceived as substandard.

Methodology

The team adopted a qualitative and comparative research approach involving:

• Semi-structured interviews with residents in four BNG developments: Delft, Belhar, Fisantekraal, and Atlantis.

• Surveys assessing satisfaction, safety, and perceptions of ABTs.

• Interviews with ABT suppliers and construction companies to gather insights into technology, cost, and feasibility.

• Cost comparison analyses between traditional brick construction and various ABTs.

Key Findings

1. Most Maintenance Issues Are Not Material-Related

From seven recurring issues in BNG homes — including leaky ceilings, cracked walls, broken windows, and mold — only two (cracks and mold) could be attributed to construction materials. The rest were due to poor workmanship, not the structural method. However, some ABTs could mitigate mold and cracking with better moisture control and insulation.

2. Ventilation and Safety Are Top Resident Concerns

Residents consistently pointed to poor air circulation as a health hazard. Many linked respiratory illnesses in their families to lack of proper airflow. Additionally, crime and gangsterism led residents to demand burglar bars and enclosed yards, highlighting a gap in the safety-focused design of BNG units.

3. Public Perception of ABTs Is Based on Misunderstanding

While many people were skeptical of ABTs, their hesitation was largely based on lack of exposure and understanding. Most residents equated “alternative” with “cheap” or “untrustworthy.” However, when they physically interacted with ABT-built homes, their trust and interest increased significantly.

4. Labor Dynamics Must Be Considered

ABTs generally require fewer specialized tradespeople and enable faster construction, which can be both an advantage and a challenge. While this can lower costs and expand the labor pool to include unskilled workers, it also contradicts the DHS goal of creating employment through labor-intensive housing projects.

Evaluation of Alternative Building Technologies (ABTs)

The team investigated several ABTs and their application in the South African context:

1. Interlocking Compressed Earth Blocks (ICEBs)

   • Pros: Low cost, energy efficient, uses local materials

   • Cons: Vulnerable to water damage without proper sealing

2. Moladi Construction System

   • Pros: Rapid wall casting, reduces waste, cost-effective

   • Cons: Requires plastic formwork and training for builders

3. Expanded Polystyrene (EPS) Panels

   • Pros: Excellent insulation, fast construction, lightweight

   • Cons: Requires cladding to meet fire codes

4. Light Steel Frame (LSF) Construction

   • Pros: Durable, recyclable, precise

   • Cons: High material cost, requires factory fabrication

5. Shipping Containers

   • Pros: Recycled material, strong and secure

   • Cons: Requires extensive insulation and ventilation

Each method offers a mix of cost savings, environmental benefits, and structural soundness, but faces barriers related to public trust, regulation, and labor compatibility.

Cost Comparison: ABTs vs. Conventional Housing

The report found that:

• Moladi and ICEBs could reduce construction costs by up to 30% compared to traditional methods.

• Construction timelines were shortened by 40–60%, allowing more units to be built in less time.

• Long-term energy savings (especially with EPS) benefited residents by reducing monthly utility bills.

However, upfront investment in training and quality control is necessary to avoid construction defects.

 Resident Feedback

• 73% of residents reported dissatisfaction with the current housing quality.

• 64% would be open to ABT homes if the structures proved durable and safe.

• Main suggestions included:

  • Better ventilation systems

  • Enclosed yards for security

  • More robust walls (regardless of material)

This feedback demonstrates that perceptions are flexible — residents prioritize comfort, safety, and functionality over material tradition.

Recommendations to the City of Cape Town

1. Pilot ABT Projects in multiple BNG neighborhoods to build public trust and visibility.

2. Create demonstration homes for educational tours and outreach.

3. Offer incentives to contractors and suppliers using approved ABTs.

4. Provide job training programs to teach ABT methods to local laborers.

5. Amend building codes and procurement processes to be more ABT-inclusive.

6. Engage community leaders to act as ABT ambassadors.

7. Establish a monitoring and evaluation framework to track ABT performance and resident satisfaction.

Conclusion

The housing crisis in Cape Town demands innovative, scalable, and sustainable solutions. Alternative building technologies offer a promising pathway to improving low-income housing in Cape Town — but only if public perception, labor policy, and regulatory frameworks evolve in tandem.

This report reinforces the need for a collaborative, phased approach to introducing ABTs. With smart implementation and community engagement, ABTs can transform the way affordable housing is delivered, making it faster, cheaper, and healthier for all.

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