What did you feel went well/was useful/made you think? EVERYTHING from Hockerton!  Your whole run-down on its history, original techniques (and changes since due to research and new technology).  You gave excellent stats, as ever, but MORE than in the past, which were most interesting, especially full building costs of the two newer apartment blocks. I know that a number were almost incredulous at the figures which you gave.  Even more of this in detail might be worthwhile.  We need ever more HARD and provable facts.  It was great that you told us straight, that labouring and work input of yourself and the Hockerton team was input as part of the cost, at full external rates; that immediately put a stop to anyone thinking that all such costly work was excluded and so the £1,350 per sq m was a bit of a fudge!  That sort of thing, to my mind is vital, as there are all too many, who will love to find fault with your figures, which MUST be fully defendable!

What did not go so well or needed improving?  Due to inclement weather, we could not spend as much time out seeing services (in a bit more detail) as is usual.  This would add more than your albeit very charming friends from elsewhere.

Please give a brief review of the day for publication on our web site? (If you answer here are you happy for us to add your name to the post?______)

Another wonderful, stimulating Master Class at Hockerton! Simon, Nick and Deb, you put on an excellent day of top-line tutorial on cost-effective autonomous house design and construction, which, in its fundamental science can be applied to a whole range of house and building types.  You are aware that I was commissioned in 2008 to project manage a PPS7 type house (now a para 79 house, under the current NPPF).  I asked my commissioned architect to attend one of your then Master Classes with me; she applied the science of Hockerton to our project (a stunning stone-faced mansion of 17,000 sq feet), which was designed (and audited) to perform, together with all its services, to Hockerton standards.  As a result of this, our project application was passed by the Planning Committee 13 to 1 in favour and only the second such house in history to be passed without going to appeal.

Nick Woolley                                                 February 2020


Thanks for the great feedback Nick.

Book now on an HHP Master Class by contacting us.

Date posted: February 11, 2020 | Author: | No Comments »

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Spring is just around the corner and if you are thinking about pruning your apple and pear trees before the sap rises, we are running a training course for you. The tutor is Marc Richmond who prunes many of the orchards around her . Last year his training day was extremely good and is highly recommended. You can book onto our pruning course here on the 8th February.

My son Luke is organising a workshop on soil health in conjunction with the Land Workers Alliance in Leeds so if you are north of here this might be one for you. The event will look at how we can improve soils and take a problem-solving approach. Visits to two local farms in the area will take place the Sunday in conjunction with the LWA. Book here on soil health 1st February.

We are running a course on Sustainable Living at Hockerton Housing Project 7th March and places have nearly all gone so do consider booking soon if you’re planning to come. Book now on Sustainable Living.

Later in the year there is a farm hack events in Meanwood urban farm, Leeds. Here you will need an idea to make some equipment for a farm/small holding/allotment or share a skill with others. A skilled tutor with a load of equipment will facilitate making your idea if appropriate. This will happen over the weekend of 6th March.

Every 2nd Tuesday of the month people are gathering in Southwell to discuss positive “green” actions. Meeting in the Admiral Rodney around 8pm please join Green Drinks then. The next meeting is 11th February 2020.

If you have a group that wants to visit Hockerton Housing Project you can design your own tour and set the date. We also run remote tours especially suitable for schools who have limited budget and a lot of children. These include a live “skype” tour around a house with one of the project members and a package of specific films on various topics with activity sheets.

We are running a repeat of the very successful peg loom workshop we ran last year. Here you will make a natural wool rug and take home the loom to make as many more as you wish, please contact us for more information. 22nd February 2020.

And finally if you want to know more about us our shop has a sale on with all our book chapters reduced to 50p each, loads of good detailed analyse for you.

We have a climate emergency to tackle and tactics start now!


Date posted: January 17, 2020 | Author: | No Comments »

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Long term solution to carbon storage with oak heat battery houses.

The start of 2020 seems to be a good time to envisage the future. What will housing look like in 2100? How will we build low impact, warm houses that also act as a carbon store? We have understood super insulation combined with thermal mass and passive design is key to achieving warmth through the winter and “coolth” in the summer but how can you do this and deliver low impact and a carbon store? Here is a vision of how we might achieve these things….

 I hope we will tackle the climate crisis swiftly and decisively this year and over the coming years. Part of this will include a massive tree planting campaign which will absorb carbon, create wildlife habitats and oddly a dilemma. For the carbon absorbed by these trees to be truly removed from the atmosphere the wood will need to be kept rather than let rot back into the ground at the end of the tree’s life. I have been considering how in the future we might achieve this and solve some of the housing need questions raised above. In the following discussion I’m going to assume the benefit of high internal thermal mass is taken for read as we have covered this in depth in other articles.

I was quite surprised recently to discover that the specific heat of wood can be more than that of concrete. This could mean we can substitute high density wood for example oak for concrete in our high thermal mass housing design. (Light bulb moment!) The wood would need to be grown and in doing so would absorb carbon from the atmosphere. (And create wonderful wildlife habitats.) By using this wood in the construction of houses we would be locking up the carbon for many extra years as houses should last a very long time.

What would a high thermal wood mass, super insulated house look like? The penalty of using wood instead of concrete is that the density of oak is about a third of that of concrete. This means more of it would have to be used inside the insulated envelope to store the same amount of energy. However, because it has a higher specific heat than that of concrete the net result would be that about double the volume would be required. The sacrifice here would possibly be lower internal floor space however this effect could be mitigated by using more wood in the floors and ceilings. In effect the house could be very similar to the Hockerton Houses but with a slightly smaller floor – area may be 6% less.Of course, the practicalities of building in oak rather than concrete would be quite different and the material supply chain would take a long time to become sustainable. The benefits of substituting oak for concrete would be enormous though.

To finish let me emphasise that I am not suggesting building timber frame houses out of oak with insulation within the walls as this would not be able to store heat. A heat battery for a house needs to have internal mass surrounded by insulation on the outside of the building envelope. The configuration I am proposing is a thick oak structure with insulation outside this with no cold bridges of oak or any other material across the insulation layer.  

Some of the background detail: Specific heat is basically a measure of how much heat energy a material can contain. The density is how much of a material you can fit into a certain space.  The heat figure ranges I saw for concrete were 840 J/kg·K to 1800 J/kg·K (Kodur, Properties of Concrete at Elevated Temperatures, 2014) and for wood the range was 1300 J/kg·K to 2500 J/kg·K with oak being 2400 J/kg·K (EngineeringToolbox, n.d.). This makes oak a third better than the best capacity concrete. Obviously the density of these materials plays a role as well so for completeness a high density concrete  might be 2300 kg/m3 (Guo, n.d.) The density density of oak varies but typically English Brown Oak is 740 kg/m3  (EngineeringToolbox, n.d.). So, comparing concrete and oak by volume, one cubic meter of concrete could store for each degree of temperature rise 4.1MJ and wood 1.8MJ. (The arithmetic 2300 x 1800 = 4.1x 106 and 740 x 2400 = 1.8 x 106). Our explanation of how heat battery works can be found three videos down. A pine building product of cross laminated timber (CLT) is available and is well understood. CLT has the ability to store heat if configured correctly but is less dense than oak.

Incidentally I would encourage you to become a member of the Woodland Trust to help support tree planting initiatives. HHP is a member of the charter branch network. Hands up here my daughter now works there! Hockerton Housing Project has become a tree charter group and is focusing on planting trees where it can. Come and see what we have done on one of our Sustainable Living Tours of the project.

I will be discussing how sustainable houses are delivered in Westminster on the 29th January. Please come and join the event. Other speakers include:

·  Lord Best, Social Housing Leader, House of Lords

·  James Harris MA MSC, Policy and Networks Manager, Royal Town Planning Institute

·  Barry Goodchild, Professor of Housing and Urban Planning, Sheffield Hallam University

·  Anthony Probert, Programme Manager, Bioregional

·  Stewart Clements, Director, Heating and Hotwater Industry Council (HHIC)

·  Dr Steffie Broer, Director, Bright Green Futures

·  Rene Sommer Lindsay, Urban Designer and Strategic Advisor, R|S|L|ENT

·  Simon Tilley, Director, Hockerton Housing Projects

·  Emma Fletcher, Chair, Swaffham Prior Community Land Trust

·  Mikhail Riches Architects

Thanks for listening your comments would be welcome!

Simon Tilley

Mr S Tilley, CEng MEng MIMechE

Director, Hockerton Housing Project Trading Ltd

NOTES on the Climate Crisis:
National Geographic: Sea level rise, explained:
BBC: Australia bushfires north of Sydney ‘too big to put out’:
BBC: Hundreds of temperature records broken over summer:
38 Degrees: DEFRA consultation on Environmental Principles and Governance after the United Kingdom leaves the European Union: Summary report of responses from 80,826 members of the public collected by 38 Degrees:


EngineeringToolbox. (n.d.). https://www.engineeringtoolbox.com/specific-heat-capacity-d_391.html.

EngineeringToolbox. (n.d.). https://www.engineeringtoolbox.com/wood-density-d_40.html.

Guo, Z. (n.d.). https://www.sciencedirect.com/topics/engineering/concrete-density.

Kodur, V. (n.d.).

Kodur, V. (2014). Properties of Concrete at Elevated Temperatures. International Scholarly Research Notices, 2014, 468510. Retrieved 1 2, 2020, from https://hindawi.com/journals/isrn/2014/468510

Date posted: January 9, 2020 | Author: | 6 Comments »

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Thought for the week: Simon Tilley on the climate nightmare

I don’t know about you, but most of my bad dreams seem to involve helplessness. Here’s one: I’m a tall chap on a coach going down a motorway. I’ve got the seat just behind the driver, with plenty of legroom, and I’m comfortable, even serene. Then I become aware that in the distance just over the hill there’s a pile-up. The driver hasn’t noticed – indeed he’s actually accelerating a bit.

I do nothing; I’m sure he knows what he’s doing. But as we get closer, I see it is quite a big pile-up, and he still doesn’t seem to have noticed. I wonder whether I should speak up. In the end I say, in a conversational tone: ‘Looks like there’s a bit of a prang up ahead.’ He makes no reply. I repeat myself a bit louder, and two things happen. He says ‘It’s just a bit of congestion’ and one of my fellow passengers nudges me and points to a sign saying: ‘Do not speak to the driver while the vehicle is in motion.’ ‘Please be quiet,’ she says, ‘it’s not safe to speak to the driver and you’re upsetting my friend.

’You know how these things go; no one else appears to have clocked what is becoming a really obvious disaster up ahead or, if they have, seem oblivious to the danger. They go on chatting and reading and sleeping, and when I try to get their attention, they just look at me as if I were a television. And the coach continues to accelerate…

I’m screaming now, pointing ahead: ‘For God’s sake, stop! Brake! Brake hard!’

Amazingly no one seems to hear. One or two of the other passengers are looking at me with mild, bovine interest, but most are remonstrating with me for disrupting their journey. We reach the prow of the hill and I notice break fluid escaping onto the road…the hill starts to send quickly…..And then, with about a hundred yards to go before we pile into the destruction ahead, the driver applies the brake but they are soft and spongey, we start to slow but far too little and too late………….

This is where I wake up, to that overwhelming feeling of relief that it was just a dream.

I usually ask myself what led up to that dream. Often there’s a logical explanation, based somewhere in reality. When you’re asleep, your brain sorts stuff you’ve been dealing with, re-runs it by and sorts out my emotional response while you’re offline. I went on a coach to London recently for the last People’s Vote march, and I’ve been reading a book about climate breakdown, (There is No Planet-B by Mike Berners-Lee) so that explains that.

Except, of course, that isn’t really a dream. When I wake I don’t get a surge of relief, just a feeling of despair at the reality: the clear and unanswerable fact that we are on the brink of irreversible climate breakdown; the knowledge that, in their anxiety not to be alarmist the media often sits quiet, our scientists understated the danger and the ongoing complacency of some of our politicians is obvious, even when faced by the reality of fires in California and Australia, famine in South Sudan and floods in Fishlake. And I wish I’d pushed the driver out of the way and taken over the steering wheel myself earlier. The prow of the hill and the leaking brake fluid must have represented a tipping point beyond which we can not retreat. These are approaching but we don’t know when.

Everything I have done over the last two decades in Hockerton Housing Projector have been Reasonable and Proper. I’ve written articles, spoken to the media, talked with friends and family, had polite meetings with my MP, written letters and signed petitions. All to no avail. So, I fear, perhaps it’s not time to stay polite, but get arrested, to make the point. And dare to dream of a hopeful future. Nonviolent direct action is starting to turn the tide, but we don’t have long.

Every action we take counts, where we bank, where we shop and for what, how we vote and what we choose to eat, how high we have the heating and how far we travel. A better future can be envisaged but we need to act and act to make it happen now.

If you want to find out about some practical steps you can take especially if your interested in low energy housing, environmental education and or renewable energy please contact me. Or if you’d like to look at our new videos on sustainability please click here.

Best wishes Simon

Date posted: December 2, 2019 | Author: | No Comments »

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Truth, Action and Assembly: Quick update – if you are local and want to hear about the climate emergency and what to do about it please come along to one of the local XR event
https://twitter.com/xrnewark The last one at Southwell Library – XR Talk – Heading for Extinction and what to do about it ! Thursday 21st November at 7PM was well attended with over 40 people turning up.

This link shows data of the melting Arctic Ice between 1984 and 2016 very scary……https://climate.nasa.gov/news/2510/see-how-arctic-sea-ice-is-losing-its-bulwark-against-warming-summers/

It would be great if all political candidates in the area could attend! Simon Tilley the speaker would love to see James Baggaley, Jay Henderson, Robert Jenrick and David Watts there to face the facts and start to act upon them!!

·  Labour James Baggaley

·  Green Jay Henderson

·  Conservative Robert Jenrick

·  Liberal Democrat David Watts

Date posted: November 20, 2019 | Author: | No Comments »

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