a revolutionary technology

Our Technology

The Problem

There is a huge unmet demand for housing, which increases every year. In the Global South, more than one billion people lack appropriate housing. Urbanization, migration, and population growth increase the backlog every year. But even in first world countries like the United States, more than 60% of people living in urban centers struggle with housing affordability.

It is clear that there is no single cause for this global issue, and that there is no single, easy solution. But at Citra, we strongly believe that innovation is the best way to bring sustainable, affordable, and beautiful homes to as many people as possible. Unfortunately, in the past 70 years, the construction industry has not been able to innovate at the same pace as most other industries.

In the past 10 years several breakthrough technologies such as mobile internet, Computerized Numerical Control (CNC) cutting machines, robots, and parametric design have enabled us to come up with new ways of designing and building homes. We believe that our technology is a leap forward for the construction industry and that it will assist the current and coming generations in solving the global housing and climate challenges.

The Solution

Citra building technology

Materials

The Citra system is incredibly strong and of high quality while eliminating steel and reducing the external building shell to the absolute minimum: A 140 mm thick Citra wall has a five times better thermal insulation value than a 280 mm thick cavity wall. And Citra walls can easily withstand a harsh North American or European winter.

The main materials used for the Citra building technology are plaster (98% of the weight), Magnesium Oxide (1%), and Expanded Polystyrene (1%).

Citra walls are exceptionally strong when compared to conventional walls. Citra can build roofs with the same building technology. A Citra building shell is about 50% lighter than a cavity brick wall house and has a greenhouse gas footprint that is about 50% less.

The Citra plaster is a specially designed mix with a compressive strength of up to 25MPa. Both on the inside and outside, there is a 30 mm plaster layer that gives the home strength and durability.

Approved by:

Citra homes are funded by:

Advantages

Design freedom: Allow your architect to design with new freedom, unconstrained by the structural limitations of bricks and mortar.

High ceilings: Impressive double volume spaces can be added with very little extra cost, and can even be converted into upstairs rooms at a later stage.

Strength: The strength of the Citra walls can hold up to 136 kg – that’s 40 kg more than a large TV – and withstand earthquakes and winds of up to 250 km/h.

Durability: Citra homes have an exceptionally long lifespan at very low maintenance costs. None of the material degrades over time, and the only worry is to repaint the home at regular intervals to keep it in good condition.

Energy efficiency: The Citra system has high thermal resistance, with an R-value of 2.2 m²K/W – which is over five times more efficient than a standard South African cavity wall! This makes our homes cool in summer and warm in winter.

Extendibility: Due to the high-performance plaster used both internally and externally, it is very easy to extend a Citra building even with conventional materials. It only requires cutting an opening or removing a door to build on with conventional materials, connecting to the Citra wall with screws and sealing the joint between the Citra panel and the extension to prevent rainwater from coming in.

Fire resistance: The Citra building system has a fire rating of one hour – twice that of brick and mortar.

Speed of construction: The Citra system is easy to assemble, and is much faster and less invasive than standard on-site conventional building systems.

Citra technology partners:

Design

Our Design Philosophy

Our design philosophy is informed by four key principles:

1

We believe that a home is much more than a physical structure to live in. It should make its owner proud. It is where we grow up and wake up every morning. A great home is the foundation of a happy, fulfilled life.

2

We recognise that a home doesn’t stop at the doorstep – urban design, the interaction of the house with the neighborhood, and its integration with the greater community – is just as important.

3

We believe in organic design – a non-linear aesthetic that links our homes to the natural world and is an expression of a new age in home-making.

4

We believe in life cycle design, considering future extendibility and the re-use of materials at a later stage.

Our Design Tools

Citra uses a design-for-production design technique where the production and construction constraints are part of the planning from the beginning. In order to achieve great results, we use a high-end design and planning software along every step of the way:

BIM (building information modeling).

Finite Element Analysis to calculate the structural integrity of our system and buildings.

Parametric Design to customize our designs and process the data for production.

Advanced Finite Element Analysis for sun, noise, and wind to ensure that our projects fit perfectly into their project-specific environment.

Nesting Tools integrated with custom scripts to reduce waste during production.

Production

Our predesigned houses are built in a simple four-step process:

1

Cutting: We cut our material with computer-guided cutting machines that are precise to the last millimetre.

2

Assembly: The assembly of Citra panels is done in the Citra Factory in Cape Town, where the current production schedule is one house per day.

3

Erection: Once the materials are cut and assembled, putting up a house is both fast — it can be done in two days! — and easy, meaning it can be accomplished by local labor.

4

Plastering: The final stage is the application of plaster, which can take from one to two weeks, depending on the project. We use high-performance spray machines from Rockcrete and Putzmeister, and our own proprietary mix of high-performance, specialized plaster, applied at between 14 and 30 MPa of pressure.

Projects

Take a look at how we have applied this technlogy in the real world.

Explore Citra's projects