Permaculture podcast

Such a great podcast available over at abundant edge. A great range of permaculture-based interviews – go check them out.

“My guest today is Gabriel Franklin, master plasterer and the owner of the company “The Art of Plaster.” Gabriel grew up with a father who was a designer and builder who shared much of his trade with him from a young age. From the age of thirteen, Gabriel started on his dad’s bucket and cleanup crew and has been working in plastering and finish work ever since. As an artist and nature enthusiast he has traveled all over the American northeast and even as far as Australia with his trade and dedication to giving blank walls a voice with clay, lime, and gypsum plasters, saying he is inspired by artistic design and how natural materials can accentuate one’s personal experience within a living space.

In this interview Gabriel explains the difference in performance and characteristics of clay, lime and gypsum. He goes into detail about the importance of prep work and the variety of additives he uses to get specific finish effects and ad strength to his mixes. We even talk about some tricks of the trade and much more.”

Natural Building Books – My Recommendations

natural building books

In the age of the internet, I am still a huge believer in the humble natural building book. I can be drawn much deeper into a book, and stay much more focused. On our Hartwyn internship builds, I bring along my bookshelf for the interns to paw over, it’s really lovely to see!

So here, I shall list my favorite natural building books. I suspect this will be a work in progress as more come out (I’m eager to get my hands on Chris Magwood’s new one!).

If you think I have missed an important one, please add a comment!

Natural Building books

Making Better Buildings: A Comparative Guide to Sustainable Construction for Homeowners and Contractors – Chris Magwood

chris magwood building better buildings“Making better buildings” looks at each element of a build (foundations, insulation, roofing), and analyses the options available. Using handy graphics you can quickly see how the options compare to each other and which fits your criteria for construction.

It goes into a small, but concise, amount of detail for each option but will give you a good starting point for further research.


The Natural Building Companion: A Comprehensive Guide to Integrative Design and Construction – Jacob Deva Racusin & Ace McArleton

 I first became aware of Jacob and Ace at the International Straw Bale Conference in Colorado. I was hugely impressed by Jacob’s presentation and the level of thought and detail he put into his work. This book is a powerhouse of information – it is a proper read!

Continue reading

Energy efficient homes save you money

Im sure that’s not big news to a lot of you?

A recent article in the gaurdian states that:

…energy bills have continued to rise in real terms to about £1,110 a year, according to the study, in part because of higher fuel costs. If all the possible improvements outlined in the report were made, bills could drop to £560 a year.

The article focuses on the benefits of retro fitting your existing home with more insulation. A well designed, highly insulated, natural home could realistically cost less than £200 a year. 

That’s a lot of money in your pocket every year! And you get to save the world.

Cystic fibrosis – Using natural materials in the home, to create better indoor air quality. (part 1)

indoor air quality

This is the first part in a series of posts about creating healthy homes with natural materials for people who have cystic fibrosis. The following topics will be covered:

  • Part 1 – Cystic fibrosis and how indoor air quality has an impact
  • Part 2 – The design and materials choices we have chosen to create the healthiest indoor air quality
  • Part 3 – Household product choices to help cystic fibrosis

I am working with Rebecca and Daniel to renovate their home, a 1930’s semi. Rebecca is a student, studying P-DTR and a pilates instructor, Daniel is a garden designer. Rebecca has Cystic Fibrosis (CF), a genetic condition affecting more than 10,800 people in the UK. Continue reading

lime wash – How to make a hot mix

The finished limewashed house

We just finished applying a hot lime wash to our ‘Ty Twt‘ building in Wales. Here you can see the finished building.

Ty Twt with its final coat of hot lime wash.
Ty Twt with its final coat of hot lime wash.

Ty Twt is a load bearing straw bale house completed by my company, Hartwyn using our intern building model. The house was completed in 11 weeks in 2016, with a final weekend to finish up the lime and green roof just completed in July 2017. Continue reading

Passive solar explained

passive solar design

What is passive solar design?

Passive solar design is a very premise on how to use the sun to heat your home in the winter. This fantastic video by Community Rebuilds intern Rebecca Barrett sums up the fundamentals.

It’s so simple, right?

All the houses I build with my company Hartwyn use these design principles.

Largest windows are on the South side and are sheltered from the hot midday summer sun. Thermal mass in the form of earthen floors, clay plasters or rammed earth walls store the heat from the sun. Highly insulating natural fibres keeps the warmth inside to keep you cosy.

Clay plaster – The many benefits of

clay plaster in a straw bale house
earthen floors and clay plaster
clay plaster and an earthen floor – work and image by Jeffrey Hart

What are the benefits of clay plaster?

I sat down to write this article on the benefits of clay plaster. In searching for a suitable source image, found this article from Paul Fitzpatrick which far exceeds anything I could write!

Below is a quick reference of the benefits of clay plasters!


Environmental benefits of clay plaster

clay plaster in a straw bale house

  • if you make your own base plaster, material can be sourced locally, with lower or no transport costs / emissions
  • unlike gypsum (and lime, although lime re-absorbs CO2 on setting), no firing required, so lower energy use / emissions
  • totally biodegradable
  • clay doesn’t set chemically like gypsum does – it just dries; so at least for the base coat, if it dries, you can wet it and knock it back up again, which means less waste
  • no nasty chemicals


Benefits for the building

earthen floors and clay plaster

  • breathability: clay plasters prevent excess moisture in vulnerable buildings. Clays are hygroscopic – they absorb moisture if humidity is high, hold it without being damaged, and when humidity falls, release moisture back to the air. So they maintain a consistent humidity, and minimise damp, and moulds caused by condensation
  • gypsum on the other hand absorbs moisture, but it’s not breathable, as it doesn’t let moisture out again, and it gets damaged in the process – it moulds, and / or the plaster can blow, and fall off
  • clays can be used with / over other breathable materials without taking away their breathability
  • flexibility: clay is soft and pliable, and can move, like lime, without cracking; it can cope with situations where you get minor movements, and so is excellent in old houses
  • gypsum on the other hand is not flexible, and cracks with any minor movements
  • protection of timbers: lime absorbs moisture through capillary action, but with clay, there is a chemical attraction that draws moisture in – and because clay absorbs moisture at a faster rate than lime or timber, it takes moisture away from the timbers of the building, protecting them from damp, mould, rot and insects
  • plus as clay absorbs moisture, it seals and prevents water from passing right through into the structure of the building. Moisture is held and released when the air around it dries. This is why clay can be used to line a pond – clay allows so much moisture in and then provides a barrier
  • aesthetic: clay plasters are beautiful in their texture and the way they reflect light, and they have an organic, natural feel.


Health benefits from using clay plaster

clay plasters applied to loft conversion

  • clay plasters maintain a consistent relative humidity of around 50-60%, which is beneficial for people with asthma or other respiratory problems, but detrimental to dust mites, which reduces problems associated with allergies
  • they contain no nasty chemicals, and are able to absorb toxins and thus improve indoor air quality. Of course, you’ll try not to use toxic cleaners or buy toxic househould products, but in this day and age, it’s difficult to avoid toxins completely, and so clay plasters can help
  • you have to be in a room with a clay plaster to understand how beautiful, sensuous, natural, earthy (add your own epithet here) they are. They just make you feel good

Embodied Energy In A Building

embodied energy in a building

What is embodied Energy?

When we are talking about our design and material choices in a natural home, we often discuss the embodied energy. This can be defined as:

Embodied energy is the energy consumed by all of the processes associated with the production of a building, from the mining and processing of natural resources to manufacturing, transport and product delivery. Embodied energy does not include the operation and disposal of the building material, which would be considered in a life cycle approach. Embodied energy is the ‘upstream’ or ‘front-end’ component of the life cycle impact of a home.

Why does Embodied Energy Matter?

I once wrote to a well-known insulation manufacturer asking for their calculations on the embodied energy in their product. The reply came back that insulation doesn’t have an embodied energy because it saves you energy. Alarming no?

So if I build a house with the most energy intensive insulation available, and I mean really fill the house with the stuff, way over code. The fact that the building may cost the earth practically nothing to heat and cool over its lifetime… is massively overshadowed by the enormous energy debt the house is in to start with. Even if the house exists for 200 years it might never pay off its initial construction debt.

Others come to similar conclusions; in one study, A comprehensive assessment of the life cycle energy demand of passive houses, the authors concluded that a family living in a Passive House, a very high standard that demands a lot of insulation, will, over the life of the house, only use a tiny bit less energy than those who live in a conventional house.

Like this author, they conclude that the only way to seriously reduce our life cycle energy cost is to live in smaller apartments downtown, but that is another slideshow.

But when you look at the list of materials in the passive house they studied (on TreeHugger here) you see it is full of 135 cubic meters of polyurethane foam insulation, sixty cubic meters of concrete, clay brick cladding and clay tile roof. There is a seriously high amount of embodied energy and carbon in this house.


Read more in this great slideshow from Lloyd Alter @ treehugger –

This is a series where I take my lectures presented as adjunct professor teaching sustainable design at Ryerson University School of Interior Design in Toronto, and distill them down to a sort of Pecha Kucha slide show.