Building for a zero carbon future

Would you like to live or work in a warm, draft free, healthy space that is easy and cost effective to heat?

Transforming our leaky buildings to make them clean, green, healthy and affordable to heat is a big project, but we have all the knowledge and tools we need to do it – and it offers us many additional benefits. Here is a selection of good ideas on how we can transform our existing buildings and build new ones in much more energy efficient ways, so we have better places to live and work, and support the shift to a zero carbon future. Continue reading “Building for a zero carbon future”

Zero Carbon Britain: Making it Happen

It’s now almost ten years since CAT’s first Zero Carbon Britain report was published. Today zero carbon is becoming a much more commonly accepted goal – but we urgently need to make it happen! Paul Allen introduces a new report, due out in spring, that looks at the barriers to getting to zero and how these can be overcome.

On 5 October 2016, the threshold number of signatories to the Paris Agreement was achieved, enabling it to enter into force on 4 November 2016. This historic agreement is underpinned by a global consensus of science that clearly recognises the need to reach zero carbon. Fortunately, a wide range of detailed scenarios and real-life practical projects clearly demonstrate that we already have the tools and technologies needed to get us there.  Continue reading “Zero Carbon Britain: Making it Happen”

“Facilitative dialogues” – Paul Allen at the UN climate talks

Marrakech is turning out to be a different kind of meeting from Paris, but that does not make it less important, in fact quite the opposite.  If Paris was about creating the framework, Marrakech is about deciding the rules so that goals are achieved.

paulearthThe most common phrase of the day in almost every session I have attended is “increasing ambition”. This can be done by turning up the guilt or it can be done by increasing inspiration – showing both that zero is achievable and that there are additional benefits in doing it. Of course, the key advantage of the latter approach is that it is less divisive and works better to unite communities across the globe.

So many people want to accelerate the transition to the zero carbon economy. People around the world are taking action to install solar and wind solutions, block coal and oil infrastructure and protect forests. People want a different future and are creating it. This determination has grown stronger and louder since Paris.

Marrakech must ensure that this increase in ambition results in plans that match the global goals. So this is why so many need to talk about increasing ambition, as the 1.5C goal really can’t wait. However, just like Paris, Marrakech is driven by incredibly complex negotiating processes. And, thankfully, just like Paris, it has attracted an amazingly bright and highly motivated collaborative global tribe inside and outside of the official process. Working amongst them constantly inspires me, as they get to grips with it all and work out how best to influence the process, flagging up the key issues and phrases.

Perhaps the most important phrase to get to grips with at this point is “Facilitative dialogue”. Due to begin in 2018, this cop22-monday-7thdescribes the official COP process of ratcheting up ambition. It is a chance for countries to take stock of how close they are to achieving the key long-term goals of peaking emissions and achieving net zero emissions early in the second half of the century.

“Facilitative dialogues” are designed to inform the next round of Nationally Determined Contributions (NDCs) – the pledges that each country makes to show their contribution to tackling climate change. Once countries have a clearer idea of the direction of travel, they will have the motivation to either update or communicate their new NDC by 2020.

It is an incredible feeling to join these astounding people in this process, everyone I have spoken to about our Zero Carbon Britain work sees a clear role for more positive scenarios in increasing ambition for NDCs. This will be the core topic of the first session run by the American Pavilion facilitated by the World Resources Institute – I will be there to see how it goes, and to offer America a hug!

Once again climate has become the focus of global diplomacy

Up-beat delegates and observers from across the globe are now arriving in a surprisingly wet Marrakech for the 2016 UN Conference of the Parties (COP22) – Paul Allen reports.

cop22-monday-7thIn many ways, COP22 will be under a lot less pressure than its Parisian forerunner. It will not be a high-profile event, which allows space for higher quality, more detailed conversations. Coming into global force last Friday, the Paris Agreement established both the commitment and the framework for dealing with climate, but although many here are happy with the “well below 2C” goal, the means to actually deliver it require a lot more complex research and negotiations. So COP22 is really aiming at fleshing out the detail. Some key questions being explored include:

How should we track progress?

How can countries increase ambition?

How can poor nations be supported?

How does all this link to adaptation?

And not least…

Who will be the next US president – and how will that affect progress?

So perhaps the most important over-arching task for everyone participating at Marrakech is sorting out the Nationally Determined Contributions (NDCs) from COP21.  These form the basis of the Paris Agreement; they are the pledges that each country laid out at last year’s negotiations, showing their contribution to tackling climate.

The first and foremost challenge is that, cumulatively, the current pledges fall well short of achieving COP21’s “well below 2C” temperature goal, and many are waiting to see if this will be an open public discourse or an elephant in the room.  But, in addition, the NDCs are very diverse in format, as countries have been working to very different baselines – which makes it hard to quantify their cumulative impact. So at COP22, delegates will begin demystifying this process by creating a more uniform framework for future NDCs.

The ‘global stocktake’ is one of the key elements of the COP process, designed to deal with the recognition that current NDCs will not meet the “well below 2C” temperature goals. Stocktakes regularly assess collective progress towards meeting the goals, and are part of the ratchet mechanism that is designed to raise nations’ ambitions.  Worryingly, the first one does not take place until 2023 although there will be a test run, called the “facilitative dialogue”, in 2018 – we need to make sure this sets a good pace.

I feel confident we will see progress during COP22. Zero Carbon Britain has been invited to the COP to present robust scenarios showing that we can get to zero carbon, to support those working to raise ambition. Despite the rain, the atmosphere feels very positive this afternoon as I sit observing the first meeting of the technology framework negotiations. If the speed with which the Paris Agreement was ratified is anything to go by, there is commitment. This early ratification means that once-distant deadlines have been brought forward to drive forward action during these coming 10 days.

Ask an expert: eco refurbishments

Want to refurbish your home in a sustainable way? With over 25 years’ experience, including as tutor on CAT’s Eco Refurbishment course, Nick Parsons has some great advice – here are his top tips.

1. Make it air-tight.

Stop unintentional ventilation (this involves designating an air-tightness layer – and sticking to it!) and design in sufficient intentional ventilation. For a whole-house retrofit this will almost certainly be whole-house mechanical ventilation with heat recovery (MVHR), but for incremental retrofits, or those with less stringent air-tightness targets, passive ventilation may suffice.

2. Insulate, insulate, insulate!

Don’t automatically believe that Building Regulations standards of insulation are enough. They aren’t bad, but in many cases we should be aiming for far better. If you have the space – and the money – Passive House levels of insulation (U values of 0.15W/m2K or less) and air-tightness (less than one air change per hour for the refurbishment EnerPHit standard) can dramatically reduce your heating requirements and massively improve comfort.

External insulation of solid walls will make your house look a bit different. Ducks are optional.
External insulation of solid walls will make your house look a bit different. Ducks are optional.

3. Insulate externally! (Unless you can’t…)

External insulation of solid walls, if detailed properly, puts the entire building fabric inside a warm ‘tea-cosy’. But it does make your house look different.

4. Risk-manage your insulation

If you have to insulate your solid walls – or sometimes even add insulation to your cavity walls – internally, excellent detailing is critical. Insulating walls internally makes the room warmer but makes the walls themselves colder and more at risk of interstitial condensation – condensation within the new thickness of the wall, behind the insulation. This can rot joist ends and other embedded timbers, and maybe grow mould. Cold walls may also suffer from deterioration of the masonry due to frost damage.

If you insulate internally, make the whole process a documented risk management exercise – identify the risks, identify control measures and document how you will implement them. In certain circumstances, consider embedding sensors and monitoring equipment in hidden timbers so that you can know if moisture levels become critical. The expense may be off-putting, but it will be a great deal less than the remedial works if you have inadvertently shortened the life of your house by doing what you thought was the ‘right thing’.

In general the use of ‘breathable’ (water-vapour-permeable) insulants such as wood-fibre or cork may reduce risks, but very careful detailing is still required.

Greater risks exist with non-breathable insulants, but if they are installed with extreme care, the risks may be capable of being ‘managed’ and minimised. If you are installing them yourself, take advice from someone with a lot of experience. If someone else is installing them for you, are they experienced with such boards? Do they fully understand interstitial condensation and vapour control layers (VCLs)? Have they read the manufacturer’s installation instructions?

5. …and consider its environmental impact

Materials such as plastic insulation – made from crude oil – are high in embodied energy (the energy, including transport, used to get the product from raw material to the merchant’s shelf), but look at the units used. If the measure is weight, a heavy bit of ‘green’ insulation may be higher in embodied energy than a much lighter piece of ‘non-green’ insulation.

You may in any case wish to avoid wherever possible materials made from petrochemicals.

But ‘environment’ may mean more than ‘the world in general’. What about your immediate living environment? You may feel better in a room lined with vapour-permeable, moisture-buffering wood-fibre than in a room lined with petrochemical-based insulation.

6. Minimise thermal bridging

dscf3495You may believe – perhaps because your builder or consultant told you – that having low (good) U values guarantees good performance but thermal performance may be let down by weak-points in the insulation layer. Typically this would be where partition or party walls interrupt the insulation layer, where walls turn into windows or doors, or where internal insulation has to be thinner to accommodate fixtures or fittings. In practice, your U value may not be as low as you believed it to be.

The picture on the left shows: on the left, a wall prepared for insulation to ‘return’ on to internal wall to cloak the thermal bridge; in the middle, Pavadentro wood-fibre board prior to plastering; and on the right an existing brick wall with a lime ‘parge coat’ (air-tightness layer) to reduce air-leakage through voids in the brick wall.

 

7. Minimise thermal by-pass

Thermal by-pass, or ‘wind-wash’, occurs when cold air is allowed to get to the ‘warm side’ of the insulation. This can best be explained in two scenarios:

The first is a loft-conversion. The eaves areas are cold voids. The stud walls to the room (which are built off the floorboards) have been insulated to a good standard but there is only 100mm of insulation between the 150mm floor joists.

The ventilation air which enters at the eaves vents (a good ‘howling gale’ to keep all the timbers healthy) can blow directly under the floor of the heated bedroom, providing instant cooling!
Small pieces of plywood or similar board, sealed at all perimeters, placed between the joists at the edge of the floor on both sides of the bedroom will cure the problem. ‘Plugs’ of quilt insulation placed in the gaps will not do such a good job (as quilt insulation is generally air-permeable), but will be better than nothing. Once these gaps have been sealed, the insulation should in any case be increased to approximately 300mm.

The second scenario involves insulation to the sloping ceilings above an attic bedroom, carried out, as the law requires, by roofing contractors when re-roofing the house.

The house was sold and the new owner decided to remove all the attic ceilings. All but about six of the sheets of insulation fell out from between the rafters. What this tells us is that, while the insulation was in place, the cold air in the ventilation gap between the insulation and the slates was able to migrate to the warm side of the insulation, rendering the insulation almost useless.

8. Plan to do it all!

Many insulation plans are carried out incrementally, perhaps as other work is required, or when a room needs comprehensive re-decoration or (externally) when the cost of re-pointing an elevation can be avoided and put towards the cost of externally insulating that elevation.

When planning your works, ideally plan to do the whole house, even if you know it is going to take you 10 years to achieve it. I’m 29 years in and starting to re-do the internal insulation using better materials and methods than were available in 1987! Plan how your individual works are going to ‘knit together’ so as to limit thermal bridges, where condensation and mould may otherwise occur.

Above all, you don’t want your works – undertaken with the best of intentions – ultimately to shorten the life of your house.

image1About the author
Nick Parsons has worked in energy-efficient and sustainable building and renewable energy for over 25 years. He provides consultancy and project management services to individuals, small businesses and community organisations and is a regular tutor at CAT and elsewhere. See www.sustainablebuilding.org.uk for details.

CAT courses
The next eco-refurbishment course with Nick takes place from 4th to 7th November. For more information and to book, please visit http://courses.cat.org.uk/ or call us on 01654 704966.