The Natural floor is done

The bedroom floor

The bedroom floor

The final lime layer of our natural floor has been put down. The floor comprises of a rock layer, followed by a cob layer and then two layers of lime plaster. We used clay and earth to add color to the lime. The first layer of lime cracked considerably and we did a series of experiments to see how best we could get the last layer not to crack. Our experiments showed that adding cement is not required, which is great.


Once the last layer of lime dried, we sealed it with a combination of linseed oil, turpentine and natural floor wax. The end result is beautiful. So far the floor is holding up well, it does not dust and is fairly waterproof. It is really easy to clean, just sweeping up dust and washing with water.

some more experiments

some more experiments


The final product – sealed with linseed oil, turpentine and beeswax

We used a combination of techniques to put the last layer of lime down. We put the floor down in one continuous go, without the use of any material to allow for expansion. It took some experimenting to crack it but the end result is amazing.


The house that Susan built

Article that appeared on the green business guide: 

The house that Susan built

What makes a house green? Is it the energy saving features? Is it the high thermal properties of the building walls? Or is it the relentless pursuit of a journey to create a home that makes as little impact on its environment as is humanly possible?

This is the question Susan and Jakkie Botha of Jeffrey’s Bay set out to answer when they decided to build a sustainable house for their mother.  Susan and Jakkie set out to prove they could build a green home using local, natural materials and could keep the cost within their limited budget.

Susan and Jakkie run a successful, edible landscape business in the Jeffrey’s Bay and Port Elizabeth area called Urban Harvest. By their own admission, they confess they knew nothing about construction and its management, so their first step was to embark on a fact-finding mission to determine which of the natural building styles would best suit their requirements.

After much consideration, sandbags were selected as the most suitable natural material to use for the construction of the house. The bags chosen to hold the sand are made of a robust geotextile material and they were readily available from the local market. The structure utilised approximately 20,000 of these specialised bags. The sand was sourced from a nearby quarry and delivered to site by the truck load. Each of the bags holds approximately 7.5kg.

The foundation was made using a crushed stone sub-base topped with sandbags. It was recommended the sandbags be filled with 1:10 cement to sand ratio for improved strength. The structural wood & galvanized sheet latticework forming the outside walls, sits directly onto the sandbag foundation. Questioning the structural integrity of sand bag walls, Susan and Jackie first carried out a field test, which demonstrated clearly that sufficient structural integrity was derived from the sheer weight of thousands of sandbags.

Although professionals were required at certain stages to fine-tune the design and the construction process, it was quite surprising and on some level, liberating to learn how the Botha sisters made use of resources available to them to achieve the majority of the build by themselves. They made use of a free version of Sketchup to draw up a 3D model of their plan and received useful tips from friends such as how to use a clear, water filled hosepipe to work out their levels.

Knowing their limitations and understanding the need to quickly learn the construction ‘tricks of the trade’, the best thing Susan and Jakkie did was experiment, experiment and experiment some more. When they bought the plot, they spent 12 months researching and closely studying the local weather patterns.  Weather patterns are an essential observation for proper orientation and design of a passive house.  Most importantly, the sisters listened carefully to and aimed to meet their client’s requirements.

The Botha sisters were surprised to find that they were not the first to attempt such a feat. A short time searching the Internet yielded many examples of people who have succeeded in building their own house from natural materials, right here in South Africa. This was a very important find for them as a precedent had already been established and allowed them to approach local authorities with built examples that helped to explain their own application. The local building authorities’ requirements had to be taken into account as the utilities connections would have an effect on the buildings eventual orientation.

The building process itself was a series of highs and lows. It was a very steep learning curve for the sisters, involving continuous experimentation with different materials of various recipes. For example, the ideal solution for the exterior walls was a wire mesh fixed to the sandbags, plastered with a cob mixture and sealed with lime/prickly pear juice mixture. This recipe was perfected after considerable experimentation. The building walls took approximately 1 month to erect, with an average of 5 people working per day. Sitting inside, one can appreciate the impressive thermal quality of the building envelope, even when gale force winds were battering the other side of the walls.

There was obviously a lot of preparation work to be done before building could begin, as the sandbags needed to be filled by hand. This is when delegation of priorities set in and team-work became an integral part of this project.

As soon as word spread that the building had commenced, many people expressed a desire to be part of this exciting project. People from as far as Cape Town came to J-Bay to volunteer their services and expertise. This was truly becoming a community project. Susan and Jakkie were also able to raise much needed funds with practical courses during the construction process.

In addition to the ‘natural’ building materials used for the building envelope, a solar water heater has been installed on the north facing part of the roof. The intention is to add further efficiency features such as a 50,000 litre, ferro-cement water tank for rainwater harvesting and a photovoltaic installation. A black water digester was considered, but the volume created would be too low for the system to function effectively. A composting black water system is currently being researched. It is worth noting that the roofing material was also selected on the basis of tests undertaken by manufacturers to show the effect their materials would have on rainwater collection. Some roofing materials could not guarantee that the water harvested would be suitable for residential consumption making them unsuitable.

The one factor remaining to consider is costing. What did this building cost and how does it compare to a conventional building? According to Susan, the 160m² cost approximately R450,000, which works out to approximately R2812/m². The Kitchen still needs to be accounted for, pushing the final per meter price to approximately R3500. There was a higher than usual man hours invested into the construction of this natural house. That translated into a higher total labour cost. However, there were many man hours invested but not considered in the costing as they were invested by volunteers who bartered those hours for experience. Furthermore, many of the building materials could not be considered in the per meter price as those materials were sourced at no cost. For example, the prickly pear is considered invasive and farmers were all too happy for them to be removed from their farm. The stones for the sub-base were also sourced from the adjacent properties at no cost. Another unexpected cost, considered in the final cost estimate was material loss due to theft.  Susan estimates R50,000 was lost due to theft of materials and the subsequent security costs incurred with trying to minimize such loss levels.

Through trial and tribulation, Susan and Jakkie have created a truly natural house that does not negatively affect its environment and aims to be as energy and resource efficient as possible. It will be very interesting to see how the house settles into its environment and how it evolves to become even more efficient with the addition of various technologies. The lessons learnt from this trailblazing construction will no doubt be employed in other natural buildings throughout South Africa, aiding the spread of energy efficiency in a country with limited and overstretched resources.

By: Khaled El-Jabi

Natural Building Course – 10 November 2012

Natural Building Workshop – 10 November 2012 

This one day workshop will provide you with a good overview of the entire process of building a natural home. We will tell you the story of building our sandbag house in Jeffreys Bay and give you a practical demonstration of each step from laying the foundations to applying the cob and natural lime finishes. This is a very special course, you will be told our story, from start to end, with all the insights required to start building your own house.

We will cover the following topics:

Visioning and creating a project plan for building your own home
Overview of different natural building techniques including wattle and daub
Getting your plans approved by the municipality
Laying sandbag foundations

Building walls using sandbags
Building walls using wattle and daub
Plastering with cob and natural lime

Laying down a natural floor
Cost breakdown of building

We will use powerpoint presentations to explain certain steps as well as practically building with sandbags, making cob and natural lime.

Bring pen and paper, sunscreen and a hat
We will be handling earth and other natural materials so it is advised to wear comfortable, old clothesCost: R650 (Lunch and teas will be provided)
Date: 10 November 2012 Times: 09h00 to 15h30
Venue: 3 Dandelion Close, Jeffreys Bay
Spaces are limited and bookings can be made by e-mailing

Natural Floor Experiments

We are busy putting the natural floor down – I remember this was said to be the last thing you do – so that is quite amazing. The first layer is rock and cobbles followed by a layer of cob and then two layers of lime. The layer of cobbles was compacted using a heavy “dropper”. The cob layer followed and took some time to dry. It was compacted somewhat from all the traffic on it and this makes the lime layer we are putting on a bit thicker, instead of 20 mm it is closer to 25 mm. 


The first layer of lime we added color to using a combination of two different earths, one a very deep red and the other a cream yellow. This gave us a light brown finish, since the lime does bleach out the color.

The surprising factor was the lime cracking as can be seen in the photos.

We have now done various experiments to see how we can minimize the cracking. One involves adding prickly pear juice which works well as a water repellent and we used this to seal the walls after it was plastered. Another experiment that is working well is to cover the plaster with plastic. This allows the plaster to sweat and dry slower, which minimizes cracking. We have also added 8% cement to one sample, although this is not environmentally friendly, we would like to compare the strength of this sample to the other natural ones. I have also added a photo here of one of our samples that was left without plastic and cracked. If all goes well we should be able to put the second layer of lime down within a week’s time….. can not believe we are moving into the final part! So exciting 🙂

Oh, and another tip! Mixing lime plaster with your feet can be very, very painful. Boots are recommended and gloves for your hands – happy natural building 🙂 


Natural Building Workshop

Natural Building Workshop

We invite you to a practical workshop that is designed to give you knowledge and skills to help you build your own natural home.


The workshop will be led by Jill Hogan,founder of McGregor Alternative Centre who has over 14 years of experience in natural building. The house is a sandbag house already built and although the focus will not be on building with sandbags, Susan will share all her gained experience and story of the sandbag construction. The sandbag walls have been covered with cob, and no matter what method you use for natural building, whether it is cob, wattle, adobe, rammed earth or strawbale, you use cob.

On the course, we will teach you how to make cob and there will be a mini soil identification workshop so that you can adjust the cob recipe according to your soil type. We will be building wattle and daub walls which is the traditional form of building in the Eastern Cape. We will also be demonstrating earth floors, rubble foundations and then most important lime plaster which is used as a finishing layer over the cob.


Topics that will be covered in the course include the following:

 1.  Wattle and Daub Walls We will be constructing inner walls using an ancient building technique called wattle and daub. Many historic buildings include wattle and daub walls and it has been used for at least 6 000 years. It consists of a woven wooden lattice work that is plastered with an earthen plaster (combination of earth, straw and cow dung). This technique is brilliant for inner walls since it takes up little space and is more insulating that dry walls.


2.  Earthen floors We will be building an earthen floor which contains no cement. This type of floor is far warmer than a synthetic floor and a lot cheaper to construct. Layered with stone, cob and lime, the floor is warm to the touch.

 3.  Natural Plaster We will give you an understanding of the process of plastering walls with a combination of cob and lime. Thereafter we will spent the day making our own and learning the technique of applying lime plaster. Lime plaster is one of the oldest and and hardest endurable building materials. We will teach you how to add colour to the lime using earth. This helps you to exclude toxic paints when you are building your house.


 4.  Rubble foundation Jill will guide us through the construction of a rubble foundation for a stoep. This type of foundation can be used when constructing many different types of natural homes and eliminates the use of concrete. It is brilliant, simple and very effective. And all the material can easily be sourced for free.


 What you will need:

 You are what you repeatedly do so we will be doing a lot of practical work to help you remember the theory. Be prepared for lots of physical building activity. However if you are not capable of physical work, you can still participate and monitor your own contribution in accordance with your body’s capability. There is no forced activity – you be the judge of what you can or can not do. Bring old clothes to work in, gloves, your hand cream (almond oil works wonders) for after work and a good pair of gumboots which is essential for making natural cob mixture and a torch. Remember we can have all sorts of weather, so bring something warm and wind proof. The sandbag house is fully insulated with doors and windows and when the weather is rough, we will take ourselves inside where it is warmer. A pair of gloves and scarf is a good call for the mornings. Also it would be wonderful if you could bring the following work tools: plaster board, rectangular trowel and triangular gauge.


Date: 15 to 19 August 2011

Start 15 August at 08:30 am for breakfast

Cost: The cost of the course is R1350

Places will be reserved on a first paid basis.

Please e-mail a deposit of your payment slip to book your place on the course


Catering: Two teas, breakfast and lunch will be served. All catering will be vegetarian. Please let us know if you have other special dietary requirements.


Accommodation: A range of accommodation options are available in Jeffreys Bay and since it is a small town whatever option you choose will be approximately 5 minute drive from the building location.

We have booked four basic wooden cabins at the Seaview Resort in Jeffreys Bay. Each cabin has two bedrooms, one room has a double bed and the other room three single beds. The cost is R140 per person per night. Should you be interested in sharing accommodation with other course participants, this option could work. Please indicate in your e-mails whether you would be interested in staying at the Seaview Resort.



Finally: Jill Hogan is an incredible source of knowledge and has an amazing “feel” for natural building. We will be covering such a wide range of topics on the course which makes it invaluable to anyone who would like to learn more about natural building.

 For queries related to the course please contact me at

The most beautiful gable wall

In my absence from the site a beautiful gable wall arose. It includes a little inlet for a free-standing wood using fire stove that will be placed in afterwards – we layered this with brick to protect the bags from the heat. Above it was placed a sleeper and even further up a round window (one we thought had also been stolen but was not!).

The earth we used in our natural plaster mix was obtained from an area that they are clearing for new RDP houses. Jakkie found it exactly at the right time. We had done some experiments on earth plasters sourcing earth wherever we could but on D-day all our sources pulled out. Jakkie found this earth as she drove to one of our gardens one day. With some negotiations, the tip truck delivered the earth to our site, instead of taking it to be dumped. Lovely going sister!

Thank goodness for lots of brains and technology. Jakkie suggested we re-design the gable wall above the fireplace to include an extra long lintel. In my absence, I explained how to “put the wall together” to my dearest boyfriend via Skype. You can imagine trying to describe where to do what and what is what from afar. But mr 10 out of 10 got the just of it and took a day to help the builders fly this gable wall up to the sky in two days. I think he qualifies for extra kisses upon my return.

And it looks lovely!

We have also had the wonderful addition of James, a builder, who is overseeing things. He has given my family a lot of assurance that things are moving along in his capable hands. So we move on – little by little. 


Hi All

It has been a while since I’ve written anything on the blog. The process of building a house, whilst still running a business and consulting can be all consuming. If you take a look at the gallery, you will notice that progress is being made. We have a roof, it is up. We have pretty much plastered the walls inside and out with an earth plaster…. the first layer which consists of earth, cow dung, straw and sand. We had the electric wiring done before we plastered. A week ago, some thieves ravaged our walls, pulling the wiring out, all of it, through the plaster. Sadly, in the way that it was done, we suspect that is has been someone who worked for us. Over the same time thieves broke open our container and stole a number of window and door frames. The police is not that interested in our case. We have now hired a security guard to be on site during the night at a great cost. This all happened whilst I am away in Cape Town for consulting work. The stress on my family is very big at the moment and we are all going through the motions of accepting what has happened and re-thinking the way forward. Obviously, there is a feeling of violation and the energy around the house feels very raw and hard. I have spoken to some friends who has been involved from the start and they suggested I do a vision board of what I want for the house. I have the hope of moving my consulting work forward so that I can go home in two weeks time and just focus on the house. That would be very helpful for my family but also for me…… because not being there right now is very difficult. I would also appreciate as much support as is available. If anyone feels they can pop in from the middle of June and be involved – it would be very very much appreciated. Also emails or words of support is very encouraging. It is not always having people with skill around but just people to talk to, which I find helps to get me thinking and moving in the way I should be. Having said that, I would appreciate any help and support from others who have built houses before. Being in the thick of building makes it difficult also to focus on the research that would be nice to do to choose the best options for moving forward but sometimes I also the lack to know-how for doing simple things – like doing the finishing touches around windows and doors when it comes to natural plasters or what best way to insulate the floor. I think we would like to organize some plastering workshops just to create once again a feeling of contribution and community support instead of a feeling of vulnerability and theft.

For others planning to build – advice would be not store anything on site, to place a guard there for night times once the house starts to increase in value and to keep the energy going with lots of activity around the house. We have our chins up and moving ahead…….. little by little….. one travels far.