Sisalwool Natural Fibre Insulation by Sisaltech

Introducing  Sisalwool^TM a natural fibre, non-itch insulation developed in Scotland by Sisaltech.

At a glance, ten great things about Sisalwool ^TM (in no particular order). 

1. It’s a high-performance insulation great for walls, roofs and floors.
2. It’s vapour permeable allowing older buildings to breath and moisture to transfer.
3. It has excellent acoustic properties.
4. It’s itch free.
5. The virgin sisal part supports small-scale organic farmers in east Africa (Tanzania). 
6. Sisal is an awesome perennial plant that needs very little water to grow. 
7. The recycled sisal part comes from sisal coffee bean sacks donated by coffee roasters and cafes around Scotland.
8. The wool part is recycled from "waste" sheep’s wool from the Harris Tweed industry and the British carpet Industry.
9. It was developed in Scotland. 
10. It’s beautiful – no really, it is highly aesthetically pleasing!

Sisal as a crop 

Sisal is part of the Agave family. It’s a “xerophytic perennial” meaning that it needs very little water to grow and that it lives for about 8 -12 years. The long rigid fleshy leaves taper to a sharp point. On mature plants, leaves can be up to 1.8 metres long making it an ideal fibre crop. Indeed, historically it has been used to make rope and other bindings since before the 16th century (pre Christopher Columbus) in its native central America. 

Sisal to trade out of poverty

In Tanzania, where the virgin sisal for  Sisalwool^TM insulation is sourced, small-scale farmers grow sisal as “back-up crops” in case of drought. A plan B for bad seasons. This amazing plant grows when others fail.

It was while studying in Tanzania for his MSc in Tropical Agricultural Development with the University of Reading in 2005 that Sisaltech founder John Ferguson determined to help the small-scale farmers use this drought resistant crop to trade their way out of poverty. He set up Sisaltech in 2018 as the product development brand of The East Africa Sisal Company Ltd which had founded in 2013 to import sisal.

“As droughts become more frequent with climate change, farmers are increasingly seeing Sisal as an attractive crop to grow. I thought if I was buying this fibre from small-scale farmers, exporting it to Europe and using it to make sustainable products, then it would be good for the farmers and good for the environment.” John Ferguson

During his Master’s degree, John began researching ways in which sisal could be used to create innovative products which he could manufacture and allow him to plough funds back into helping small-scale farmers in Tanzania. He began experimenting with processing sisal, previously used to make ropes and sacks, to assess its viability to create everything from ‘bags for life’ and composites for kayaks to geotextiles for erosion control, embankment stabilisation and peatland restoration. In his final stages of research, it became apparent that the fibre from the sisal plants could be used to produce a sustainable and natural insulation product which would be safe for installers to use.

Sisal and carbon footprint

The sisal leaves are stripped of their fibres in east Africa and left to dry naturally in the sun before being brushed, baled and shipped by sea to be procesed. The virgin sisal fibres are mixed with sisal fibres from recycling coffee sacks, wool and a recycled plastic binder to make the insulation.

It is because the bales of virgin sisal are transported by ship that the carbon footprint of that journey is very small. The carbon footprint of the virgin sisal is further reduced by blending it with sisal from coffee bean sacks that have already been imported into Scotland for coffee roasters and cafes. The blending of virgin and recycled sisal ensures all the great benefits of sisal but with a lower carbon footprint for the insulation while also helping towards a zero-waste economy.

Sisal Fibre Insulation

In the early start-up days of  Sisaltech, John and his small team started off by researching and developing pure sisal insulation. They discovered that it is possible to make 100% sisal insulation, but it is so rigid and tough that it’s almost impossible to cut!

They decided to blend the sisal with another natural fibre. They experimented with pretty much all the different natural fibres there are including wool, cotton, jute, wood fibre and many more.

For their first commercial product, they settled on blending the sisal with sheep’s wool. From a thermal performance, acoustic performance and fire performance, wool has got quite a lot of advantages. Of course, it also added flexibility to the insulation slabs too. In the right mix the sisal and wool creates a non-slumping friction fit slab that is also easy to cut. The wool is soft and flexible. The sisal fibre adds great strength and rigidity.

Initially Sisaltech were using all virgin materials in their insulation. Even with new sisal fibre from east Africa and even with new sheep’s wool, it's still a very low carbon final product. However, they started doing some work with Zero Waste Scotland exploring the circular economy. That collaboration took them on new journey to find out if they could recreate the same product using entirely recycled materials.

Tweed and the circular economy

Sisaltech works alongside Zero Waste Scotland to identify other perfect “waste” streams to mix with the sisal to create the high performing insulation. To create SisalWool^TM, the sisal is blended with sheep’s wool from the Harris Tweed and British wool carpet industries. Wool, as we know from our other insulation products and from wearing woolly jumpers, is has great thermal properties too.

Harris Tweed of course is another pioneering company from Scotland. Renown globally for their quality wool cloth.

Scaling a company within the circular economy

John is passionate about working in the Circular Economy and helping towards a zero-waste world. 

As a small and still relatively new company they can respond to change as opportunities arise. One batch of insulation might include off-cuts from Harris Tweed and another time they might discover that wool is available from the British carpet making industry.

“There are a lot of companies, like clothing companies, that really don't want their waste to be going to landfill. They'd like to see it going into something like insulation. So, it's quite nice being able to respond and help them to reduce their carbon footprint as well as obviously having more raw materials for ourselves.” John Ferguson

The challenge is that people expect a consistent product. Changes in the appearance of the insulation can easily confuse people who are not aware of the complications of sourcing materials within the circular economy. One batch might be white, and the next brown, or purple or multicoloured. The changes from batch to batch are purely aesthetic.

Sisaltech perform ongoing thermal testing, fire testing and so on to make sure that their products stay within the high parameters that they have set for themselves.

Sisaltech and the future

Sisaltech have sustainability at the forefront of all their decisions and consciously make every effort to be as ethical and low carbon as they possibly can be. They are on a mission to create innovative, technical, natural fibre insulation products to enable an easy switch to low carbon building materials while offering increased safety and comfort to installers.

Their aim for the future is for all the materials for their insulation to be recycled from “waste” streams.

“We believe that we have created one of the best insulation products there is. There’s the adage that, for every pound you spend is a vote for how you want the world to be” John Ferguson

Sisaltech products

At the time of writing there are three Sisalwool^TM insulation products.  Sisalwool^TM 100 and 50 (insulation batts) and Sisalwool^TM Loftroll (insulation rolls). 

Sisaltech expect to add to their range of sizes in the very near future and of course we will add them to our Sisaltech brand page so watch this space! In the meantime if you have a very large project on and are looking for a bespoke size, please  contact us for a quote and to discuss lead times.