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Here you will find the latest articles written by our insulation specialists focusing on product developments, building regulations and technical guidance notes.

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Category Archives: Regulations

The topic up for debate at the recent Round Table event at the Saint-Gobain Innovation Centre was ‘Zero Carbon – a lost cause?’ and it certainly provoked much discussion. At the table were many of the key players who were either involved in the creation of the original Zero Carbon definition, or charged with delivering it, in the form of the creation of construction products or the creation of the actual Zero Carbon houses themselves.

So, why so much debate?

The key problem with a discussion about Zero Carbon is that the target is still far from clear.

It has moved a long way from the initial ideas set out by the Labour Government in their consultation paper of 2006 ‘Building a Greener Future’ where it was stated that “Zero carbon means that, over a year, the net carbon emissions from energy use in the home would be zero”.

This original definition included all the energy, including that from non-regulated energy (white goods).  Since then, this has changed and only regulated energy (space heating and cooling, fixed lighting and ventilation) needs to be accounted for when building a Zero Carbon home. So, not really true zero carbon but at least this ties in with the way in which energy use in buildings is normally assessed through the Standard Assessment Procedure (SAP) and Code for Sustainable Homes.

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The 22nd – 26th of September is World Green Building Week and the UK Green Building Council is encouraging all of us to “Get up, Green up”.

So what can we do? What springs to mind to help reduce energy consumption?

1. Turn the TV off standby?

2. Turn out the lights when you leave the room?

3. Install low energy light bulbs for when you do need the lights on?

4. Look at you homes EPC certificate?

I expect the first 3 are very familiar but perhaps number 4 is one that may leave one or two people scratching their heads and turning to the all-knowing entity that is Google for inspiration.


An EPC is the Energy Performance Certificate for your house. Whenever you sell or rent, you must, by law have an EPC for the property. For many people, when selling the house, this is just another annoying expense top on top of all the other many forms and documents that are required at this stressful time.  The EPC survey gets done, you get the EPC report, perhaps give it a passing glance as you stuff in a file then and move onto more pressing matters as the trauma that is ‘moving house’ engulfs you.

When you move into your new house of course, there will be an EPC report waiting for you, as the previous owners will have had to get one done as well. Once again though, the fun that is unpacking boxes, sorting out utility companies, and generally trying to maintain your grip on reality tends to mean most of us will just leave the EPC report in a file, only to be discovered when we decide to move all over again.

So, the one of the best ways to help with sustainability is to Get Up, find your EPC report and see how you can Green Up your property.

An EPC rating (from A being the best through to G being as far away from great as you can get) is a bit like the housing equivalent of the miles per gallon on your car. However, the EPC report does more than just tell you the rating, it tells you how to:

  • Increase the efficiency of your home so you can move up the EPC scale
  • Reduce your home’s impact on the environment
  • Save yourself money on your energy bills.

Here is page one of an example EPC taken from the Government website


What does an EPC include?

  • Estimated energy costs of the home
  • Savings possible if improvements are made to the lighting, heating and hot water
  • Current and potential future (if recommendations are followed) Energy Efficiency Rating
  • Top actions that can be taken with cost and saving on each

Armed with this information you can set about planning the work that needs to be done to do your bit for the environment and ease the burden on your back pocket. The EPC even lists those measures that are eligible under the Government’s Green Deal scheme, where you do not have to put any money up front and the cost of the measures is paid for out of the savings on your fuel bills.

If the idea of Green Deal doesn’t appeal and you are not too fussed about having lower fuel bills there is another reason to Get Up and Green Up by following the EPC recommendations: House Prices.

Research by DECC showed that those properties with a higher EPC rating commanded a higher selling price.

EPC Rating % Higher selling price compared to ‘G’   rating
E   & F 6%
D   & E 8%
C 10%
A   & B 14%

Need more convincing?

If all that isn’t enough to convince you, there is political talk in the run up to the next general election that encouragement is needed to get the population to help reduce the CO2 emissions from existing buildings.

At the moment 27% of the UK’s CO2 emissions come from homes. How to incentivise us, the voters? Tax. It is possible that tax breaks, perhaps on Stamp Duty or Council Tax will be possible and they will be linked to ….. yes, you guessed it, the EPC rating of your home.

There are many good reasons to Get Up, Green up and seek out that EPC report. If you act upon the recommendations: your bills will reduce; your property value will go up,  and one day you might even get one over on the Tax Man. The planet will thank you as you do your bit for a sustainable environment. Everyone’s a winner.

performance gap blog image-1

How does your house perform? Ask many homeowners and they would look at you in a puzzled way and start to edge towards the door. Ask them how their car performs and you are likely get somewhere in the answer a mention of the miles per gallon. Efficiency of cars is front of mind, that of your house, unless you are unusually familiar with its EPC (Energy Performance Certificate) lurks in the back somewhere behind the more pressing issues of room sizes, quality of kitchen/bathroom and whether it has anywhere to park the car.

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scotish flag

No, not the big ‘In or out’ question on September the 18th, I am referring to an area where Scotland has been quite independent for some time – Building Regulations.

The Scottish equivalent to the English Part L is something called Section 6 and it, like its English counterpart, has been due for an amendment. There was a consultation on proposed changes that closed on 15th April 2013 and we have just had a response back after 16 months. It seems no matter what side of the border you are, the regulatory wheels turn just as slowly.

Implementation of the proposed changes will not happen until October 2015, so you could be forgiven for perhaps not caring too much right now. However, with the longer term question of what to do about Zero Carbon in 2016, the shape of Section 6 in late 2015 may give us a clue as to just what kind of specification challenge may lay ahead.

Read more »


After three months, 50 locations and over 1,000 bookings, the Celotex pink double-decker bus has parked up for the final time at our HQ in Hadleigh, Suffolk as the last day of the #InsulatingBritain roadshow.

We started in London at the Ecobuild event in March and worked our way up and down the country as part of the 50 date roadshow, holding live webinars and delivered a series of one hour technical presentations to provide expert advice and guidance on UK Building Regulations changes – Part L and Section 6.

From the start of the Insulating Britain campaign, we have seen over 2500 industry professionals educated on the UK Building Regulations. From Southampton to Glasgow, Cardiff to Norwich, the bus offered a 12-seat presentation area where members of our Celotex Technical Centre, Area Sales Managers and Product Managers educated architects, contractors and distribution partners to simplify their route to Regulatory compliance. The roadshow also helped to send over 10,000 visitors to Celotex’ purpose-built website insulatingbritain.co.uk.

“Our Insulating Britain campaign has given industry professionals across the UK easy access to everything they need to know about new UK Building Regulations, with further reductions in CO2 emissions required for England, Wales & Scotland, Celotex product and service solutions will continue to help simplify compliance to these new levels.” Paul Evans, Head of Marketing at Celotex.

The Celotex bus has completed its journey, but we will continue to provide the latest updates, information on how to simplify compliance and expert advice and guidance over the course of 2014. Keep yourself updated by checking the Insulating Britain website and follow us on twitter @Celotex.

We would like to take this opportunity to thank all who have attended the bus over the last three months and all of the venues for having us there!

If you did miss out on the bus, not to worry, you can still book yourself a CPD on the UK Building Regulations using our online form.


So the quest for The Code (for sustainable homes) is over. The Housing Standards Review has swarmed all over regulations like an army of Orcs in Middle Earth searching for those pesky Hobbits. The Code has been sacrificed but does this signal the end for the quest for Zero Carbon Homes?

Zero Carbon was supposed to happen in 2016 to coincide with the next revision to Part L. Given that Part L 2013 didn’t appear until 2014 and a General Election looms   to add extra delay, even Gandalf would struggle to pull this one out of his big grey hat. Is Zero Carbon the ‘one Ring’ that will bind together all the policies towards a common goal?

The problem is, the goal is not common. The ‘mount doom’ of climate change is just too far away for most of us. We scurry about The Shire in our own little world, focused on the everyday tasks of working, paying bills, trying to climb on the housing ladder and having the odd bit of fun if we are lucky.

A Zero Carbon Home?

Any home will do. The EPC rating? Not bothered. Living space, quality of local schools and somewhere to park the car are far more important for most. Sure, it would be great to have a new home one day that is ‘zero’ carbon but that day is a long way off and I don’t want to pay any more for it thank you very much.

Of course, the homes most us buy already exist and are along way from Zero Carbon. Bands of people have set off before on Green Deal and ECO expeditions to tackle this problem. Few have returned.

So what is the best way to get us to care about carbon emissions and tweak the nose of The Dark Lord of Climate Change? Tax. Or more precisely, tax incentives. If we got a council tax rebate for improving the energy efficiency of our homes there would be an army of homeowners ready to climb the mountain and get their metaphorical finger bitten off for a good cause …and a few extra quid in their ‘pocketses’…

Part L the approved document setting out guidelines for the conservation of fuel and power has been revised and a new edition goes live on 6th April 2014.

Amongst the changes include the introduction of:

  • 6% aggregate reduction of CO₂emissions
  • A new compulsory target based on the energy efficiency of the building fabric (FEES).  FEES sets a maximum limit on the amount of energy normally required to ensure a comfortable internal temperature in the home.
  • A new notional building to replace the existing first introduced in 2002. The new notional building promotes a strong fabric performance and sets out domestic targets for various elements linked to the building envelope. The domestic targets will for some allow consistency of specification across building types.

So as the 6th of April fast approaches what do these changes really mean and how do they affect new projects in the pipeline?

What does the 6th April actually mean?

If plans for your project have been submitted to Building Control or a Local Authority before 6th April, compliance to Part L 2013 will not apply. This is providing work has commenced on site before 6th April. This is what’s known as ‘The Transitional Arrangement’. The changes to Part L 2013 will only apply to plans submitted after 6th April 2014.

When should a SAP calculation be carried out?

Simply put, a SAP calculation is required to demonstrate a dwellings’ compliance of CO₂ emissions (TER) and Energy Consumption (TFEES) to Part L 2013.  SAP is a desktop exercise and is applied to the project both at design stage and at the final ‘as built’ stage.  A completed SAP calculation creates an Energy Performance Certificate based on the dwelling as built and is required to be displayed in a new dwelling put up for sale or rent on the open market.

It is favourable to introduce a SAP calculation at the earliest design stages. This allows the Architect to make changes to the design if at first it does not comply to the TER and TFEES required within the notional building.

If the SAP is first performed later on in the design process, perhaps by the contractor, and it fails to hit the required targets, it will be more difficult to alter elements affecting the fabric performance. For example, changing the width of a wall or altering the depth of rafters.

Have you got any handy hints to help comply with the new Regulations?

The new notional building and the introduction of a target for energy consumption points to adopting a ‘fabric first’ approach to compliance. This means ensuring the building envelope complies with key fabric targets and so prevents heat loss and reduces energy demand.


Handy hint no 1: The notional building seeks good U-values through the roof, walls and floors.  It will no longer be possible to achieve compliance using backstop values without the considerable upgrade of other key fabric targets.

Handy hint No 2: There is a new requirement for airtightness within the notional building setting a minimum value of 5m3/(h.m2) @ 50Pa.  This means tightening up on uncontrolled air leakage by correctly finishing and sealing internal linings as well as considering the benefits of air tight barriers.  Anything less than this target will mean the introduction of controlled ventilation.

Handy hint No 3:  Thermal bridging forms a key component to compliance. The junctions between walls with floors and roofs will need to be detailed to a standard better than Accredited Construction Details. In some cases there may be a requirement for the junctions to be modelled by an independent energy assessor in order to achieve compliance.

Handy hint No 4:  Party walls are fully filled and sealed to achieve the 0W/m²K required in the new notional building.

And finally, something to think about…

The changes introduced into Part L 2013 applicable to domestic dwellings are seen as a step towards the Government’s target of zero carbon in 2016.  This has introduced a fabric first approach when designing new domestic dwellings meaning key fabric energy targets are the focus for compliance.  With the 2016 zero carbon target in mind there are some that suggest targets within the new notional building are the minimum standards required especially as Part L consultations led us to expect CO₂ reductions greater than 6% on aggregate.

The key fabric energy targets for the new notional building in Part L1A 2013 is an improvement over Part L1A 2010 but should designers aim to exceed the TER and TFEE? A final SAP calculation of the DER and DFEE rate is required to take into account any changes in performance between design and construction.  It could be that designing to standards better than TER and TFEE not only has a favourable impact on CO2 emissions, it also allows for any last minute changes in design and so ensures building performance while adopting a fabric first approach.

For more information on the UK Building Regulations and to download your Part L Guide, visit the Insulating Britain website.


It’s been an amazing last few days as we have all got on board with the changes to the new Part L 2013 for England due to go live April 6th. In particular, it is with great excitement we welcome one particular change to how domestic NEW builds achieve compliance and that is the introduction of a compulsory metric for the performance of the building fabric as part of SAP (TFEE). The introduction of this new metric is a step towards the 2016 target that all newly built dwellings should be net zero carbon.  This means new buildings after 2016 will not add further to CO² emissions.

In the midst of focusing on the changes to the new Part L 2013, I just wanted to pause from all the excitement, take a step back and think about the other half of the Part L story.  The part that’s not changing and that’s energy efficiency measures for EXISTING domestic and non-domestic buildings. This includes our homes, work places and social venues, childcare centres and public buildings to name but a few. (Wales aside, they are introducing their own compliance guidelines for the conservation of fuel and power to include existing buildings which are called Part L 2014 Wales due to go live 31st July).

Carbon Emissions

The Climate change Act 2008 requires that by 2050 UK’s annual Carbon Dioxide emissions are reduced by 80% compared to 1990 levels.  It is understood that home energy use is responsible for over 25% of UK’s CO² emissions and whilst the Government’s commitment to net zero carbon target for 2016 seems to be on course, the 2050 target presents the nagging question ‘Should we be improving the energy performance of existing dwellings as well as new dwellings to achieve the required 80% cut in CO² emissions across the entire housing stock?’

Having said this and I don’t want to spoil the party,  there’s an undeniable fact that homes built before 2016 will still exist in 2050 and so will be the subject of a refurbishment project to further improve the standard of energy efficiency in order to meet the 2050 target of 80% reduced CO² emissions. 

Even more reason to support the fabric first approach in today’s designs, do that little bit more today to protect tomorrow and why we welcome the new compulsory target fabric energy efficiency metric in SAP.

So having made the point ‘what about existing dwellings, they’re relevant too?’ what can we do, as professionals in the industry, to support the Government’s long term goal of an 80% reduction in CO² emissions in dwellings? 

ECO and Green Deal

Well the good news is the consultation document on the future of ECO (the Energy Company Obligation) was published 5th March and will run until 16th April. Its goal is to reduce pressures on consumer bills and provide value for money to consumers.  In doing so, it will tackle fuel poverty, support the development of sustainable energy efficiency supply chain and improve energy efficiency of our housing stock.  This will hopefully make funding more simple and supply more accessible.

So while the officials work to provide more certainty to ECO and the green deal, we can try to better understand and become more familiar with what reducing CO² emissions look like in our existing homes.  How do we approach a sustainable refurbishment project and translate the reduction in CO² emissions into improvements around the house which will mean less energy consumption and lower energy bills?

Fabric First

Adopting a fabric first whole house approach is a really good place to start. This allows for detailed planning and careful preparation when considering how to form the thermal envelope of a building. Key areas for design consideration when adopting a fabric first approach include

  • Building fabric U-values of floors, walls and roofs
  • U-values of windows and doors
  • Thermal bridging
  • Air Tightness
  • Thermal Mass

Knowing when…

…to improve the energy efficiency of the building is key. Refurbishment projects can be costly so may occur once or twice in a 20 year period.  With this in mind it makes sense to take every opportunity where practical to achieve the best possible level of thermal upgrading during a refurbishment. Timely opportunities include having a new kitchen fitted, an extension built, re-roofing or re-plastering are but a few.

There are other positive measures that can be taken to improve the CO² emissions of a building such as introducing a more efficient boiler for hot water and heating and using energy efficient light bulbs to name but a few but these are not directly linked to the building envelope and the fabric.  Having a fantastically efficient boiler is brilliant but if the fabric is poorly insulated all that lovely warmth will escape meaning further energy consumption.

We can only wait to see how the other half of the Part L story unfolds in the future. It’s no secret that a significant portion of the existing housing stock has poor levels of insulation and airtightness which increase heating demand and energy consumption. Adopting a fabric first approach for the whole of the building when planning a sustainable refurbishment project will minimise heat loss through the building envelope.  This in return will reduce the heating demand and energy consumption of the property which in turn again will have a favourable impact on the reduction of CO² emissions and the target set for 2050.

For more information on the UK Building Regulations visit the Insulating Britain website.