Tag: Lizzie Stoodley

HPH259 : Constructing the masonry superstructure of Portree Passivhaus – with Mike Coe

Mike Coe has a progress report from Portree Passivhaus, which is now almost watertight. We pick up the story as the groundworks begin and look at some of the challenges as the superstructure has gone up.

Mike Coe on the roof at Portree Passivhaus

Interview with Mike Coe

Mike Coe has been on the podcast a number of times. Our first interview with him was when he completed building the Cropthorne Autonomous House, where we imagined he might stay put for many years. However, with concerns over climate change, he and his partner Lizzie Stoodley decided to move further north to the Isle of Skye in Scotland.

This meant selling the autonomous house, which was not straightforward, and taking on a second project with well known architects Rural Design.

A section of Portree Passivhaus

A visualisation of the finished house

The sloping site was perfect for upside down living

Mike’s previous house, the Cropthorne Autonomous House, had bedrooms downstairs, and the living space and kitchen upstairs. Mike prefers this layout and was keen to repeat it.

That’s why one of the attractions of the site was its slope. The main entrance could be at the top of the house, taking you directly into the living space.

The dig begins

‘Rotten rock’ is discovered

Rotten Rock provides a perfect base from which to build

Mike explains that whenever anyone builds on Skye they look for ‘rotten rock’, which is a combination of the normal clay subsoil but with volcanic small rock particles mixed in. This makes a stable foundation that you can build straight onto.

Although they were digging into the hill, the rotten rock is almost solid enough to dispense with a retaining wall (but not quite!).

The Cropthorne Autonomous House

His first self build guided a lot of decisions

At the autonomous house the heavyweight structure of the building was used as a thermal store, which would build up heat during the summer and slowly give it back over the winter.

Hence Mike wanted to repeat what he knew worked well. Portree Passivhaus is a masonry building with a cavity wall.

This is unusual for Scotland which has a lot of timber frame buildings, that are quick to put up in the inclement weather.

Resilience was another key factor

The building’s heavyweight structure will also make it a ‘fortress’ for whatever weather is to come.

I think it’s inevitable that we’re going to get more extreme weather. We haven’t had that much of it in the UK yet, but there’s rarely a week when there isn’t some kind of extreme weather event somewhere in the world which makes it into the news.

The slab of insulation goes in

The building sits on a tray of insulation

Concrete is poured into a tray of insulation to form the lower ground floor slab. The internal concrete block walls then get built onto the edges of that slab, so the internal part of the house is completely isolated.

The cavity wall is 375mm wide and uses TeploTies for low thermal transmissivity.

With a large open plan living area, the building requires a steel structure for extra support.

The first floor is a beam and block floor, and above this there will be a green roof.

We’ve got a very substantial roof structure in order to take the weight of the soil on which the grass will grow on the roof. But below that, sitting on top of the structural I-beams, there’s another layer of insulation.

There is no environmentally benign dwelling

Mike is well informed when it comes to climate change and believes that we, as a world, could be doing so much more to reduce carbon emissions. So why is he building with masonry when more sustainable materials exist?

There’s undoubtedly embodied energy in this house. How significant it is in terms of global carbon emissions compared to things that could be very, very easily avoided, I don’t know. In use, the house will have a tiny environmental footprint. It’s very energy efficient, it doesn’t have a heating system, it’ll have renewable energy systems as well.

Although it will be a number of years into the future, Mike says the house will pay back its CO2 debt. And for him it’s not just about preventing climate change, this is a house that’s ready to face the extreme weather events that have been caused by climate change.

When you look to the future it’s not going to blow down. And the turf roof is part of the resilience strategy.

Mike installing the ventilation ducting

Mike gradually took on more responsibility

Having been very hands-on during his first self build, he had wanted to do less this time. However, he’s found himself being drawn in!

Due to concerns over finances, he decided to save some money by installing the mechanical ventilation system and doing all the electrics himself.

But knowing the level of detail required on a project like this, he’s also monitoring quality.

It’s all about during and post construction quality control. And trying to get across the message that the insulation has got to be kept clean and dry – difficult in this climate – as dry as possible and put in neatly without any gaps – I don’t know why but it’s just proved to be very tough.

So Mike has spent weekends pulling insulation out, cleaning it, putting it back again. He’s also taken responsibility for some of the trickier details.

Mike spotted a thermal bridge across the cavity

With an architect and contractor who haven’t built a Passivhaus before, Mike’s experience has become extremely useful. During construction he noticed that the steel was creating a thermal bridge across the cavity.

The solution was to shorten the steels and put thermal break pads in. Using stainless steel bolts also helped reduce the transmission across the steel.

Delays have had an upside

Mike’s contractor has had to start another project for a local hotel and this has meant a reduced workforce on Mike’s site.

However, as pensioners, Mike and Lizzie have been able to squirrel away extra cash.

This gives Mike cautious optimism that he could get towards the end of the project… and even hire decorators (something they’d really like to do).

Stone cladding begins

The main living space

Find out more

Visit the website of Portree Passivhaus

Follow Mike Coe on Twitter

Follow Portree Passivhaus on Twitter

Transcript

Download a transcript of the interview with Mike Coe.

Please connect with me

Subscribe, rate and review the podcast in iTunes

Rate and review the podcast on Stitcher

Like our Facebook page

Follow us on Twitter

July 29, 2019
From Passivhaus . . . to conventional house?

What makes someone swap the comfort of a Passivhaus self-build for a conventional 1960s bungalow? Former ITV news cameraman Mike Coe explains his unexpected transition.

When Mike Coe built his ultra-low-energy eco-build – the Cropthorne Autonomous House in Worcestershire – after he retired in 2006, he was determined to make a difference.

Water neutral and off-grid apart from electricity, the house trod as lightly on the earth’s surface as possible. It encapsulated Mike’s optimism that UK housebuilding was on the cusp of change.

But five years on, after much soul-searching, Mike and his partner Lizzie made the difficult decision to move on.

A shift in values, combined with an appetite for new adventure, has taken the couple from the comfort of a Passivhaus with no heating system, which never fell below 16°C even on the chilliest of winter nights – to a three-bed 1960s bungalow in Portree on the Isle of Skye. So what changed?

The comfortable Passivhaus they left behind

Reality check

“When we built The Autonomous House, I naively thought I was on the vanguard of some kind of movement in ultra-low energy homes,” says Mike. “But while I was attempting to build as ecologically as I possibly could, the government was in the process of trashing UK planning laws and allowing developers to build rubbish wherever they wanted. I became disillusioned quite quickly.

“I still feel The Autonomous House itself has value and was a great project – but I lost my sense of optimism that it was the dawn of a new era.”

Their current home – a traditionally built 1960s bungalow – is merely a temporary stop-over as they embark on another self-build challenge. And while Mike’s focus has changed since building his radical, largely off-grid Passivhaus, he hasn’t lost faith in low-energy building methods.

“I still try to live in an environmentally sympathetic way – and my next house will be a Passivhaus,” says Mike. “But I no longer think anything I’m doing will have any great impact on the world.

“Since retiring I returned to work as a cameraman, but only on carefully selected, mostly environmental projects. As a result I’ve met some of the world’s leading climate scientists and been able to talk to them informally. From what I’ve learned I’ve concluded that it could become uncomfortably hot in the south of England, even in my lifetime (I’m 60 now). This realisation was the trigger for a decision to move as far north as was practical without leaving the country – and we’ve ended up in Portree.”

Portree

Skye’s the limit

In planning their move north, Mike’s original intention wasn’t to build again. Despite being very practical and capable – having done all the electrics, plumbing and more at Cropthorne – he doesn’t particularly enjoy the building process. The couple’s first thought was to find an existing house that they could adapt.

“It quickly became obvious that we wouldn’t find anything that came close to what we had at Cropthorne in the areas we wanted to move to,” says Mike. “Once you’ve lived in a Passivhaus it’s very hard to settle for a conventional draughty house that’s expensive to heat and live in. So we decided to look for a temporary house, while we considered our options.”

It was during this search that they heard about a building plot with planning – that also had ready-made accommodation on site.

“While it wasn’t our intention to build again, the site we found, almost accidentally, had so much potential,” says Mike. “It had nine acres of croft land, two building plots with Permission in Principle (the Scottish equivalent of Outline Planning Permission) and a perfectly acceptable bungalow on site that we could move straight into. It was too good an opportunity to miss.

“It’s rare to find somewhere with ready-made accommodation on site when you build. We can build a south-facing, solar-heated home here with views over Portree harbour and distant views of the Cuillins. It’s perfect.”

View from the Croft

‘Conventional’ house v Passivhaus

So how does living back in a ‘normal’ home compare to the comfort of living in the Cropthorne Passivhaus?

“The most notable thing is how rapidly the temperature inside conventional buildings follows the temperature outside,” says Mike. “The heating goes off and half an hour later you notice that it’s really cooling down. Two hours later, it’s freezing.

“In our Passivhaus, which was high-mass with thermal storage in the structure of the building, the process was slowed down. In autumn, when you started getting chilly nights, you simply weren’t aware of it.

“Living here has made me realise how lucky we’ve been to live in a Passivhaus. The bungalow’s clunky old oil boiler drinks kerosene that I have to pay for. It’s not cheap – whereas at Cropthorne we had no heating bills, and it was more comfortable. That’s a stark contrast.”

The warm and cosy upstairs at the Cropthorne Autonomous House

Laying plans for a new adventure

What of Mike’s plans for the new build? Have his shifting views led to a fundamentally different approach this time?

“It will still be a very low energy design for both comfort and running costs, because it’s a good way to live,” says Mike. “It just won’t have unrealistic goals.

“With the Cropthorne project we were quite hard line. The house used entirely harvested rainwater, we had composting toilets, and everything was designed to minimise impact. We’ll still follow that path to some extent. For example, we’ll aim for zero heat, even though the climate here is different. There’s also a stream running down the site that should be capable of powering a small hydro generator to provide some of our electricity. Eventually we may even add a wind turbine.

“But this house will have more mainstream appeal. The autonomous systems at Cropthorne were brilliant but they added to the costs, and you don’t get those back when you sell. We had practical reasons for doing what we did there. On Skye, water is in abundant supply, so we’ll probably connect to the mains.

“So, overall, the new house will still be very comfortable, environmentally benign and energy-efficient, but will be more mainstream and more saleable – just in case I have another brilliant idea in five years’ time and we end up moving again!”

Artist’s impression of Portree Passivhaus

July 10, 2017
What is an Autonomous House?

Do you feel that you’re lacking a connection with your environment?

Would you like to live in a house where you are in control of the services?

This article is a case study of a couple who created an autonomous house. We find out why they did it and how different it is to live this way.

Autonomous Means Possessing a Large Degree of Self-Governance

Mike Coe and Lizzie Stoodley built themselves an autonomous house in Cropthorne, Worcestershire. Although being autonomous might imply no connection to the outside world, in their case this is not strictly true because they are linked to the grid (albeit to export more electricity than they use!).

If they were completely self-sufficient and off-grid in all respects they would have an autarkic house, but autonomous is a better description of their home. They have no gas supply, they derive their water from harvested rain and they deal with their own human waste.

Architects Brenda and Robert Vale Inspired Them

The initial seed of an idea came in the 1990s, before they had any plans to build a house. Mike was an ITV News cameraman and he was sent to Southwell, Nottinghamshire, on an assignment to do a story on a new kind of house.

Mike describes his visit: “Nobody had the faintest idea what it was. Only when I got there did I realise that it was fascinating. We did an interview with Robert Vale and he showed us around and I thought this is a really interesting project.”

The feature was never shown on ITV because another story broke, but Mike’s journey was not in vain. He had been inspired.

Many years later Mike and Lizzie were considering a long-term plan to leave London and live somewhere less hectic, when they returned to the idea of an autonomous house.

Increasingly concerned about what the human race was doing to the environment and with a strong desire to take action somehow, the ideas came together in their ultra low energy house. It would be based on the house at Southwell but would try to take everything to the next level, with improved materials and greater experience, etc. As this was a once-in-a-lifetime opportunity they wanted to do this properly and take the ideas as far as was sensible.

In 2006 Mike and Lizzie bought their plot of land

Passivhaus Offered the Best Approach

Mike was convinced that the basic configuration of Brenda and Robert Vale’s house was correct. It had a very high thermal mass – based on a concrete core – surrounded by a huge amount of insulation, built as airtight as possible with super high performance windows. Although Brenda and Robert Vale’s house had a small wood stove, Mike and Lizzie believed they could create a house that didn’t need a heating system and just relied on incidental heat (body warmth, cooking, heat from appliances and so on).

While the house was designed and constructed using Passivhaus principles it hasn’t been certified, although this could (easily) be done at a later date. In fact the primary energy requirement of their house is between 3 – 4 kWh per m²per year, which is four to five times better than the Passivhaus requirement.

An Inverted Layout Takes Advantage of the Fact That Heat Rises

In terms of design the house is upside-down. So the living area is upstairs, taking advantage of the fact that heat rises. In a house with no heating it makes sense to live where it’s warmer during the winter. Also, during very hot summer weather, the bedrooms, being downstairs, stay cool and are therefore more comfortable.

If Mike ever builds another house he would definitely do it the same way again.

You Must be Adaptable to Live Like This

Living in an autonomous house requires more thought than a conventional dwelling. However, it’s good thought! The user needs to understand how the building works in order to get the most out of it. For example, controlling the temperature is about considering what to do with the heat. During the summer, Mike and Lizzie warm up the core of the house to a comfortable temperature. They make sure that they close windows and doors when they need to store up heat for the winter. Also, in autumn and winter the mechanical ventilation system is in heat reclaim mode whereas during the summer they don’t reclaim any heat.

Mike says: “You’re much more in touch with the seasons and the outdoor environment and you modify your behaviour accordingly. You have to be prepared in the depths of winter to wear a jumper.”

Responsibility for Resources is Back with You

In today’s world, so long as we have money we know (or perceive) we can have the resources. This not only shifts the responsibility onto somebody else – our service providers – but it distances us from what we’re actually doing to the environment. To live in an autonomous house it is necessary to be more in touch with the environment which Mike sees as a very good thing.

Mike and Lizzie have 17 tonnes of water storage in their basement, but they still need to modify their behaviour if they are anticipating a prolonged period of dry weather. This might mean not cleaning the car or taking showers less often.

“We derive all of our water supply from water that falls on the roof. We store it, we purify it, we drink it, we wash in it and we wash our clothes in it. And it ends up back in a soakaway in the garden.”

The same amount of water enters the site as would have done had the house never been built. All they do is borrow it.

Mains Electricity Makes Sense at the Moment

Mike explains that it’s not environmentally and economically sensible to go off-grid if you have access to a mains electricity supply. This is because storing electricity is not straightforward. For example they could use banks of lithium or nickel metal hydride accumulators but they contain a lot of chemicals. Plus, with this set-up there might still be trouble supplying the house at periods of peak demand.

So, at the current time there is little financial or environmental advantage. Instead they effectively use the grid as a battery!

Most of the electricity generated by their 2.3kW ground-mounted photovoltaic array gets exported because the energy demands of the house are so low. At night time they consume power from the grid, but it’s a small amount. The total electricity bill for the house is in the region of £350 per year and as the payment they receive from the photovoltaic array is about £900, they make about £500 income.

Mains Water and Sewage Systems are Not Efficient

There’s a lot of energy involved in providing houses with clean water and removing the sewage.

While doing his research Mike discovered that 30 – 40% of the water consumed in a normal house is used for flushing the toilets. In most cases it is also clean drinking water, which is of course very wasteful.

Human waste is actually quite a useful substance because it has similar properties to a fertiliser. Mike sums it up well: “What we normally do is we mix useful human waste with useful clean drinking water and we produce a problem substance called sewage, which we then have to pump several miles using energy and process it in a local sewage treatment plant.”

The composting toilet being installed

Composting Toilets Made Sense

With heating and lighting, adjusting lifestyle can often result in huge energy savings. However, when it’s comes to human waste you can’t really reduce the number of times you need to go to the loo! That’s why Mike and Lizzie were keen to bring all those services in house and provide them without using any external energy.

Mike explains how it works: “Every two months, with two of us living here, we have to maintain the chamber which means we have to drain out all the liquid compost and we have to take out the solid compost [that’s mixed with wood shavings], but by the time you come to do that it genuinely isn’t unpleasant.”

This compost then goes on the garden and this also means that they don’t need to buy any fertilisers.

In the Event of Fuel Shortages, They Would be Well Placed

Building an ultra low energy house is in a sense adding an element of autonomy, because you’re reducing your reliance on external fuel supplies. Reflecting on how their life would alter in times of scarcity or blackouts, Mike says they would stay warm because there’s no heating system to go off! There would be no issues with their water either. Electricity would be fine during the day but they might be inconvenienced with a prolonged power cut.

Running an Autonomous House is Rewarding

Mike and Lizzie have never looked back since embracing this way of living. Mike concludes: “The main thing is you have to think and you have to want to be responsible for your actions. That isn’t a hardship – it’s quite rewarding. I think it’s a good way to live.”

October 18, 2013