Polyfoam XPS - The Build Up

It can be a minefield picking out the differences between construction products, especially with so many competing claims about what is the ‘best’ solution.

Insulation solutions are the perfect example – all offer a low thermal conductivity, but exactly how low do you need to go? Does it automatically follow that the insulation with the lowest thermal conductivity is the ‘best’ solution?

It all depends what you are specifying a solution for. Here at The Build Up, we try to take a broader view of building construction and performance, aiming for the best quality and the best long-term outcomes. This month we’re getting into the correct calculation of ground floor U-values, and looking at a comparison between XPS and PIR insulation. Read on to find out more.

If you’ve enjoyed this newsletter, or if you have suggestions for topics you’d like to see us cover in future editions, send us an email or reach us via LinkedIn.

Demystifying Standards

Architects and specifiers are often told that they need to know all about standards and codes of practice. But many standards are big documents with a hefty price tag, meaning they are not always accessible or digestible. Our blog post series is demystifying some of those standards.
Men pouring screeed on ground floor

What do architects need to know about calculating U-values for ground floors?

Last month we looked at the fundamentals of U-value calculations and what you needed to know about the combined method. This month, we’ve written about the specifics of ground floor U-values. Heat loss through a ground floor is different to any other construction element, and we look at the detail of what information helps us to provide you with the most accurate calculation.

Read our blog post to learn everything you need to know about BS EN ISO 13370

Design Resources

Raw material shortages, international shipping delays and product price increases are all putting a squeeze on the construction industry at the moment. It’s more common than ever for contractors to seek approval for alternative solutions that are more readily available or more cost effective.

If you’re a regular specifier of PIR insulation and you’re finding that price rises and product shortages are hampering your projects, you might be interested in our new article that sets out why XPS could be your new go-to floor insulation of choice.

Read more about our comparison of XPS and PIR floor insulation here.

Technical Support for BS6229

Getting More From Polyfoam XPS

So far in this issue of The Build Up we’ve looked at U-values for ground floors, and comparisons between XPS and PIR insulation.

We’re developing a range of resources about why XPS insulation is the ideal ground floor insulation solution. You can view our accredited online CPD session, and in the next few weeks we’ll publish a new white paper looking in detail at ground floor performance requirements and insulation options.

We are also developing a white paper and other resources looking at the use of XPS insulation in the base of masonry cavity walls, below DPC level.

While we work on these new in-depth publications, you can download our current white paper on inverted flat roof specification, including the assessment and certification of insulation systems


What Caught Our Eye This Month ?


Thanks for reading this issue of The Build Up by Polyfoam XPS. To receive the new issue every month SUBSCRIBE


Insulants in the shape of houses

Polyisocyanurate (PIR) and extruded polystyrene (XPS) are both lightweight, rigid foam boards used for thermal insulation in buildings.

It might be assumed that the two materials share a number of similarities, but both have their own characteristics that mean they are actually very different. The result is that they are typically better suited for different applications.

At the time of writing in mid-2021, PIR insulation has seen a number of price increases linked to the supply of raw materials required to manufacture it. In addition, issues with the transportation of those raw materials have affected the availability of PIR in the UK market. Specifiers and contractors have therefore found themselves looking for alternative insulation solutions.

This blog post will help you to understand some of the key qualities that distinguish XPS from PIR insulation. Armed with that understanding, you’ll be able to make informed decisions about when and why XPS might be your preferred insulation on a construction project.

What is the thermal performance of XPS compared to PIR insulation?

The primary reason for specifying thermal insulation materials in building projects is to reduce heat transmission, energy demand and carbon emissions. Insulation materials are therefore heavily promoted based on their thermal conductivity, where the lower the value, the lower the heat energy conducted by the material.

Most PIR insulation products offered for general applications such as ground floors and pitched roofs have a thermal conductivity of 0.022 W/mK. This performance is achieved in part by the foil facing on the insulation boards, which must remain intact to ensure the declared performance is delivered consistently. With a damaged foil facing, the thermal conductivity achieved can be more in the region of 0.026 to 0.028 W/mK.

An XPS insulation product usually achieves a thermal conductivity of around 0.033 W/mK. This is higher than PIR, so a slightly thicker XPS product is required to deliver an equivalent thermal performance. When insulation products are so commonly marketed on the basis of offering the thinnest possible solution, this seemingly puts XPS at a disadvantage.

One thing to keep in mind, though, is that XPS products don’t depend on a foil facing to achieve their stated performance.

What are other performance characteristics of XPS insulation compared to PIR?

A misconception that we often encounter is the belief that PIR performs better than other materials across all categories, simply because it happens to offer a better thermal conductivity. For example, people can think that PIR must also offer a better load-bearing capacity.

A typical PIR insulation board offers a declared compressive strength of 120 kPa, and can be as high as 150 kPa. The lowest grade of XPS typically offers 200 kPa, with the majority of product sold offering 300 kPa. Other grades of XPS are available, offering a compressive strength as high as 500 kPa.

For some applications, this distinction has little relevance. In a pitched roof, for example, compressive strength has no bearing on the suitability of the insulation. Solutions that can achieve the required U-value with minimum thickness are desirable to save space and maintain head heights, for which reason we don’t offer XPS products for pitched roofs.

In a ground floor construction, however, compressive strength is a much more important characteristic. Thickness is less of a concern, because a slight increase in insulation thickness can usually be accommodated with relative ease. XPS insulation comes into its own for ground floor build-ups, and it has other qualities that arguably make it a better choice than PIR.

How does XPS compare to PIR as a ground floor insulation solution?

Misunderstandings around the performance of insulation products extend to the way in which they are designed and installed as part of ground floor build-ups.

A PIR insulation board has to be positioned above the damp proof membrane (DPM), to protect it from ground moisture. It also has to be positioned below the air and vapour control layer (AVCL), both to limit any potential risk of condensation in the floor, and to protect the foil facing from reacting with alkalis in any screed installed over it.

Even when designers indicate insulation in the correct position within the floor build-up, it is not uncommon for PIR to be installed directly against the ground, with the DPM installed above.

Without correct installation, there is a risk that the performance of PIR insulation will be compromised due to moisture exposure, or damage to the foil facing. XPS insulation, meanwhile, has a lower moisture absorption and is manufactured without any facings. Its thermal performance therefore cannot be compromised due to incorrect installation relative to the membrane layers in the floor.

Specifying XPS insulation for ground floor build-ups

XPS insulation can be specified for installation directly on the hardcore and sand blinding layers of a ground floor construction, with the confidence that it will maintain its performance in the event of limited exposure to ground moisture.

The DPM can be installed over the insulation and also act as the AVCL. This saving in time and cost compared to using two separate membrane layers might sound relatively modest for a single property or extension project, but across a development of multiple units it could add up.

You can still choose to design a floor with XPS between two membranes, for added reassurance. Crucially, if the installer then chooses to put the XPS in contact with the ground without your knowledge, you have the confidence that the product specified will still deliver the anticipated U-values over the life of the building – something that might not be the case for incorrectly installed PIR boards.

About Polyfoam XPS products for ground floors

The Floorboard range from Polyfoam XPS – which includes Floorboard Standard and Floorboard Extra – can be specified and installed in a range of ground floor build-ups, from domestic projects to commercial and industrial buildings.

Polyfoam XPS’s extruded polystyrene products are manufactured at its base in Hartlepool in the north east of England, for distribution across the UK. To find out more about using XPS in ground floors, contact us with any technical enquiries, or view our short online CPD session.

We have written a white paper providing a comprehensive guide to thermal insulation products in ground floors. To find out as soon as it is available to download, subscribe to our monthly email newsletter, The Build-Up.


Man Screeding

The transfer of heat energy from a building into the ground is very different to heat transfer through an external wall or roof. As a result, the way in which U-values are calculated for ground floor constructions is different to how they are calculated for other building elements.

For architects and specifiers, it isn’t necessary to have a detailed knowledge of the standard that describes this different method. What is worth knowing, however, are some of the factors that influence the calculation outcome. Armed with this knowledge, ground floor build-ups can be specified with the confidence that they will deliver their designed performance once in service.

Before getting into the detail of ground floor calculations, you might like to read our general introduction to calculating U-values, including BS EN ISO 6946:2017 and the combined method.

What is BS EN ISO 13370:2017?

Because of the thermal properties of the ground, it used to be the case that ground floors were not insulated. The continued development of energy efficiency requirements in building regulations means that option no longer exists.

BS EN ISO 13370:2017 Thermal performance of buildings – Heat transfer via the ground – Calculation methods sets out how thermal transmittance can be calculated for slab on ground floors (often called ‘solid floors’), suspended floors (such as timber joist or beam and block constructions), and basements.

A basement is defined as a usable part of the building that is partly or wholly below ground level, and the calculation method includes basement walls as well as basement floors.

Generally speaking, a ground floor U-value calculation starts by calculating the total thermal resistance of the layers of the floor construction. This is done as per the method described in BS EN ISO 6946:2017, so all the layers need to be of consistent thickness and properties, with any repeating thermal bridges taken into account.

What variables should you be aware of when requesting ground floor U-value calculations?

The variables associated with ground floor constructions impact on the accuracy of the U-value calculations, and therefore the contribution of those U-value calculations to SAP and SBEM calculations.

Heat loss from a ground floor is greater at the edge of the floor than at the centre. Arguably, therefore, the most significant variable is the size and shape of the floor, expressed by the total floor area and the length of the exposed perimeter.

The temperature of the ground in the UK remains in a fairly narrow window throughout the year, but the variability in the external climate at the edge of the floor increases the rate of heat loss. Where the edge of a floor meets the external air, or an enclosed space that is unheated, that edge is classed as part of the ‘exposed perimeter’.

Two buildings can have the same length of exposed perimeter, but be a completely different shape. The perimeter therefore bounds a significantly different heated floor area. The relationship between exposed perimeter and heated floor area is essentially an expression of how simple (or not) a building’s form is.

How does the type of soil affect a ground floor U-value calculation?

A ground floor U-value calculation is affected by the type of soil on which the building is constructed. BS EN ISO 13370 describes three categories of ground, each with a different thermal conductivity.

CategorySoil typeThermal conductivity (W/mK)
1Clay or silt1.5
2Sand or gravel2.0
3Homogeneous rock3.5

While soil in the UK is typically clay, if the ground type has not been confirmed for a project-specific calculation then it should not be assumed that the lowest thermal conductivity can be used. The standard addresses this, saying: “If the ground type is unknown, category 2 should be used.”

Assuming the wrong soil type for a ground floor can lead to a significant difference between the result of a U-value calculation and the actual performance of the floor once constructed.

About Polyfoam XPS

A ground floor U-value calculation from Polyfoam XPS is backed by our technical team’s many years of experience in the construction industry and insulation manufacturing. This blog post only offers an overview of some of the factors affecting ground floor calculations.

For example, there are a range of factors that influence suspended floor calculations and basement calculations.

Whenever we receive a U-value calculation request, we work closely with the designer or specifier to ensure that the result we produce is appropriate to the project and an accurate reflection of the proposed design.

Request a calculation from us today by contacting us about your project, find out more about standards on our blog, or view our short online CPD session all about ground floor insulation.


Polyfoam XPS - The Build Up

What makes a high quality building? The style of architecture? The feel of the internal finishes? Or the underlying building performance?

An argument could be made for any of those three things individually, or how they all interact in combination. A strong argument can be made that the highest quality buildings deliver energy efficiency and thermal comfort, with good indoor air quality and acoustic comfort as well.

The experience and knowledge required to routinely deliver high quality, high performance buildings exists – and a wealth of it is available for anybody to take advantage of. That ‘s what this month’s issue is about.

Feedback and suggestions are always welcome by email, or reach us via the LinkedIn button at the bottom of the newsletter.

Demystifying Standards

Architects and specifiers are often told that they need to know all about standards and codes of practice. But many standards are big documents with a hefty price tag, meaning they are not always accessible or digestible. Our blog post series is demystifying some of those standards.

What do architects need to know about BS EN ISO 6946?

There are multiple facets to building performance, but the starting point for many is the U-values that different building elements have to achieve to keep thermal transmittance low. How are U-values calculated? Read our blog post to learn everything you need to know about the BS EN ISO 6946 standard.

Design Resources

We’ve never had the pleasure of working on a project with the team at Greengauge Building Energy Consultants, but their newsletter is one we always look out for in our inbox. Each month The Heat of the Moment features Greengauge’s own detailed and authoritative construction-related insights, alongside interesting bits and pieces that have caught the attention of the team. Subscribe to the newsletter at the Greengauge website.

For designers looking to gain a better understanding of energy efficient buildings or to learn more about the Passivhaus standard, the Passivhaus in Plain English blog archive is an ideal place to start. As the name of the blog suggests, architect and Passive House Designer, Elrond Burrell, spent several years posting about building performance in a way that is accessible to all readers.


Getting More From Polyfoam XPS

  • What is XPS insulation?
  • How does it perform compared to other common insulation types?
  • What makes it the ideal, robust choice for insulating ground floors?

Our CPD presentation, accredited by the CPD Certification Service, answers all of these questions and more in just fifteen minutes of your time. View the session online and claim your CPD certificate today.


What Caught Our Eye This Month ?

  • Young Indian designer transforms building energy modelling (via CIAT)
  • World’s first 3D-printed steel footbridge and digital twin completed (via BIM +)


Thanks for reading this issue of The Build Up by Polyfoam XPS. To receive the new issue every month SUBSCRIBE



The required thermal transmission – aka U-value – for a construction element (floor, wall or roof) determines the thickness of thermal insulation that has to be incorporated within that element’s build-up.

For architects and specifiers, accurate U-value calculations are therefore essential – whether seeking to ‘only’ achieve the minimum building regulations compliance, or meeting higher levels of performance through voluntary standards and assessment methods. How much do you know about how U-values are calculated, and how much do you need to know? Read on to find out!

What is BS EN ISO 6946:2017?

From a building physics perspective, the movement of heat energy through building materials is complex. This complexity increases in construction elements that are themselves built up in a complex way, and thermal transmittance can only be calculated through a method known as numerical modelling.

Many elements, however, essentially comprise a series of layers. Most of these layers are a uniform thickness of a single material, while some feature regular ‘interruptions’ such as a timber structure or metal fixings.

For these build-ups, a simplified form of calculation called the combined method can be used to calculate U-values. It is this simplified ‘combined method’ that is set out in BS EN ISO 6946, the current version of which is the 2017 edition.

The ‘BS EN ISO’ part of the title indicates that it is a British and European Standard adopted from an internationally agreed standard.

Who uses U-value calculations produced by the combined method?

The simple answer is: a lot of people!

If you or your practice produce your own U-value calculations then you will probably use a software program that is based on the methodology set out in BS EN ISO 6946.

If you request U-value calculations from external consultants or product manufacturers, then most of the calculations you receive will follow the combined method. Somewhere on the calculation, it will probably state that the result has been calculated to BS EN ISO 6946 (it may also refer to a document called BR 443, which you can read more about here).

Because of its simplified nature, using the combined method is much faster than relying on numerical modelling for all calculations. The details of the combined method set out in BS EN ISO 6946 have been validated by numerical modelling, so it can be used with confidence – as long as it is applied to the correct types of constructions.

Do I need to know BS EN ISO 6946 in detail?

The answer to this question depends on how closely you engage with U-value calculations.

For anybody carrying out calculations and working out insulation thicknesses, it is helpful to know some of the underlying ‘workings’ of the methodology. Rather than just accepting the output of the software, it can help to explain why the software is producing the result that it is – and can help to steer design decisions long before formal calculations even need to be undertaken.

In addition, if you go down the route of gaining training or accreditation in calculating U-values, it might be necessary to produce some U-value calculations by hand. That is not possible without understanding the mathematical processes involved.

For construction professionals who obtain calculations from consultants and product manufacturers, it is generally the case that you are relying on the knowledge of the person or organisation producing the calculation. While it may not be necessary to understand the mathematics of the calculation method, it is important to engage with the party doing the calculation to ensure that your proposed build-up is being properly represented.

We said that the method needs to be applied to the correct types of constructions, and this is essential. Unfortunately, there are too many occasions where people try to obtain U-values for complex constructions that go beyond the limit of the combined method. Software programs depend on the ability of the user, and cannot identify when the user is trying to model a scenario that cannot be accurately represented.

Equally unfortunately, we have also experienced occasions where somebody has asked us to carry out a U-value calculation that is unsuitable for the combined method.

When we explain that what they’re asking for needs to be calculated by numerical modelling instead, they become frustrated at the need to source an alternative type of calculation – rather than appreciating that we have saved them from obtaining a calculation that could have fundamentally misrepresented the performance of their design.

About Polyfoam XPS

When you request a U-value calculation from Polyfoam XPS, you can do so with the confidence that you’re benefiting from our team’s many years of experience in the construction industry and insulation manufacturing.

We work closely with architects to ensure that the combined method calculations we produce are appropriate to the project and an accurate reflection of the proposed design.

To find out more about our technical support offering, contact us about your project, read more about standards and current construction trends on our blog, view our online CPD session, or subscribe to receive our monthly newsletter.


Polyfoam XPS - The Build Up

Welcome to the June edition of The Build Up, and welcome to the increasing numbers of you subscribing. Thanks for reading and choosing to have us drop into your inbox on the last Friday of every month.

We’ve covered some different and varied topics over the last few months, but we’re back on familiar territory in this edition: flat roofing. As ever, please send your feedback or suggestions to us by email, or reach us via LinkedIn. 

Demystifying Standards

Architects and specifiers are often told that they need to know all about standards and codes of practice. But many standards are big documents with a hefty price tag, meaning they are not always accessible or digestible. Our new blog post series is demystifying some of those standards.

This month’s subject is a document called ETAG 031. How does it affect the inverted roof solutions you specify, and how much do you need to know about it?


What do architects need to know about ETAG031?

For architects and specifiers looking to include an inverted flat roof as part of a construction project, ETAG 031 is a document that is very likely to be referenced in technical literature for inverted roof solutions. But what is ETAG 031, and how much do you need to know about it to help you successfully specify an inverted roof? Find out about ETAG 031 here.

Design Resources

A few newsletters ago we mentioned Passive House + magazine, and their excellent in-depth coverage of low energy construction. In June they hosted their first online roundtable event, with an impressive array of expert speakers discussing the topic of thermal bridging. The event is free to view online here.

With over 300 to choose from, it’s impossible to single out one episode of the House Planning Help podcast as being the best place to start listening. The podcast covers every aspect of self-build and low energy design and construction. Many of the huge variety of subjects are of interest to designers and specifiers, and the guest is always an expert with lots of practical experience. Our recommendation: look for a topic that interests you, and start from there!

Technical Support for BS6229

Getting More From Polyfoam XPS

Whether it’s guidance on designing and specifying extruded polystyrene (XPS) insulation, or U-value calculations and condensation risk analyses, we’ve got you covered.

Polyfoam XPS’s technical staff have years of experience in the construction industry generally, and insulation manufacturing specifically, and are on hand to offer advice and answer questions at any stage of a project. Contact us through the website or email technical@polyfoamxps.co.uk.


What Caught Our Eye This Month ?

  • Willmott Dixon maps waste firms to reduce carbon emissions (via bimplus)
  • UKGBC launches new Solutions Library to enable sustainable buildings (via CIAT)
  • Three new tools to reduce embodied carbon (via bimplus)


Thanks for reading this issue of The Build Up by Polyfoam XPS. To ensure you receive next months issue please subscribe.


green roof XPS

For architects and specifiers looking to include an inverted flat roof as part of a construction project, ETAG 031 is a document that is very likely to be referenced in technical literature for inverted roof solutions. But what is ETAG 031, and how much do you need to know about it to help you successfully specify an inverted roof?

An ETAG, or European technical approval guidelines, provides a basis on which certain construction products can be assessed. A formal assessment body can use an ETAG to issue a European technical assessment (ETA). ETAs are a route by which products can be conformity assessed (i.e. CE marked) when no harmonised standard exists for that product.

What parts of an inverted roof does ETAG 031 cover?

The guidelines of ETAG 031 cover what is known as the inverted roof ‘kit’, a name given to the combination of thermal insulation and water flow reducing layer (WFRL).

The kit is installed, loose laid, on the waterproofed roof deck. The performance of the waterproofing is not impacted by the inverted roof system above it, or vice versa. Inverted roof waterproofing is therefore not part of ETAG 031’s guidelines.

The insulation and WFRL are secured by means of ballast such as gravel, paving slabs or a green roof system. ETAG 031 recognises these components as a “set generic specification” in terms of how they affect, or may be affected by, the performance of the kit. Together with the ‘kit’ these components make up what ETAG 031 calls the inverted roof ‘system’.

Are inverted roofs assessed to ETAG 031 in the UK?

Thermal insulation materials used in inverted roof systems are already the subject of harmonised standards. Extruded polystyrene, for example, is covered by EN 13164. This means they can be conformity assessed without the need for an ETA – and, indeed, must carry conformity assessment in order to comply with the Construction Products Regulations.

ETAG 031 refers to two insulation materials as being suitable for inverted roofs: extruded polystyrene (XPS) manufactured to EN 13164, or expanded polystyrene (EPS) manufactured to EN 13163. Both harmonised standards are referenced in ETAG 031, so an insulation material conforming to either standard is therefore considered suitable by ETAG 031.

Inverted roof kits are assessed at the national level for an Agrément certificate, such as a BBA certificate. Certification is made more straightforward thanks to the insulation being manufactured to a harmonised standard.

Certificates may not directly reference ETAG 031 – for example, the BBA certificate for Polyfoam XPS’s inverted roof kit does not mention it – but the guidelines are still important.

ETAG 031 and inverted roof performance

Arguably the most significant aspect of ETAG 031 is its description of how to test and assess the performance of inverted roof kits in terms of the WFRL restricting the passage of rainwater through the insulation layer to the waterproofed deck.

Insulation manufacturers looking to obtain an Agrément certificate for their kit must have the WFRL tested in accordance with the method set out in ETAG 031. The results from this testing have a direct impact on every U-value calculation undertaken for an inverted roof featuring that kit.

This, then, is the area in which architects may take most interest in ETAG 031. An in-depth knowledge of ETAG 031’s contents is not essential. Being confident that the chosen insulation manufacturer is using the declared results of WFRL testing, however, and understanding that a project’s inverted U-value calculations have been properly adjusted, is important from a compliance and performance perspective.

About Polyfoam XPS

This blog post is simply an overview of what aspects of ETAG 031 are likely to be of most interest to design professionals and specifiers. For a much deeper exploration of inverted roof performance, standards, and Agrément certification, download Polyfoam XPS’s white paper.

Polyfoam XPS supplies an inverted roof kit comprising Polyfoam Roofboard Extra insulation, manufactured to EN 13164, and Polyfoam Slimline Zero membrane WFRL. Our solution is certified by the BBA.

Find out more about Polyfoam XPS and our complete range of products,  or learn more about current industry issues and product performance in our  blog.

Alternatively, to find out how we can help with flooring or roofing solutions for your project, contact us.


Polyfoam XPS - The Build Up

Welcome to May’s edition of The Build Up. In the spirit of being clear and unambiguous, let’s get straight down to business. As always, if you want to get in touch, you can contact us here or reach us via the LinkedIn button at the bottom of the newsletter.

Demystifying Standards

Architects and specifiers are often told that they need to know all about standards and codes of practice. But many standards are big documents with a hefty price tag, meaning they are not always accessible or digestible. Our latest blog post series sets out to demystify some of those standards.


What do architects need to know about the Code for Construction Product Information?

This month we’re focusing on the Code for Construction Product Information. What is it and how might it effect the way you work? Although not yet officially launched, a recent consultation on a draft version has shone a spotlight on how designers and specifiers might interact with product manufacturers in the future. Find out what you need to know about the CCPI here.

Design Resources

Following on from the theme of this month’s featured blog post, the two resources we’re highlighting both do an excellent job of making complex information more accessible and clearer to understand.

The Designing Buildings Wiki is a crowd-sourced hub of construction knowledge, backed by high profile associations and organisations. There is an existing wealth of information, to which anybody can contribute in accordance with the site’s guidelines.

Building Regulations are a notoriously complex set of documents. The third edition of Guide to the Building Regulations sets out the structure of the regulations, their requirements, and the technical guidance of the Approved Documents, in a way that is easy to navigate and is arguably more logical than the ‘official’ publications. Approved Document B has been updated a number of times since the book’s publication date, but it remains a useful reference.

A construction office

Getting More From Polyfoam XPS

On the subject of making information about construction products clearer and more accessible, why not book one of our CPD sessions?

What is extruded polystyrene (XPS) insulation? How does it perform compared to other common insulation types? What makes it the ideal choice for below ground, ground floor, and inverted flat roof applications?

Our CPD presentation, accredited by the CPD Certification Service, answers all of these questions. View the seminar online (coming soon) or contact us to arrange online delivery to your team.


What Caught Our Eye This Month ?

  • Tallest modular building in the world completes construction (via CIAT)
  • Building insulation: Is hydrogen our get out of jail free card? (via Energy Monitor)
  • Concrete batteries could create rechargeable buildings (via CIAT)
  • Building Services Design and Energy Modelling for Local Authority Housing Scheme (via GreenGauge)


Thanks for reading this issue of The Build Up by Polyfoam XPS. To ensure you receive next months issue please subscribe.



At the end of March 2021, consultation closed on a draft Code for Construction Product Information (CCPI). The draft Code has been prepared by the Marketing Integrity Group (MIG), an industry body set up by the Construction Products Association (CPA) in response to Dame Judith Hackitt’s report Building A Safer Future.

The Code is aimed at manufacturers of construction products. It sets out 11 clauses that, when the Code is implemented, will need to be met in order for a manufacturer to be deemed code-compliant.

By meeting the 11 clauses, it is intended that a manufacturer is demonstrating their commitment to providing the industry with product information that meets five tests: clear, accurate, up-to-date, accessible and unambiguous.

Should design professionals be familiar with the CCPI?

At the time of writing the consultation response is still being analysed. The CCPI has not been formally launched, and therefore manufacturers cannot claim to be compliant.

As a result, design professionals cannot yet choose whether to work only with manufacturers who have the CCPI ‘badge’. As one of the primary users of construction product information, however, we felt it worth producing this blog post to help inform about the progress of the Code.

The CPA has been forthright in announcing its intention to push the Code through, regardless of feedback. As an architect or design professional, therefore, you can expect to see news of its launch (if you didn’t already know about it), and manufacturers starting to display the badge, in due course.

Will the CCPI make a difference to how you find and use product information?

That is the big question!

The Code is being heavily promoted to manufacturers, with suggestions that organisations risk being ‘left behind’ if they don’t adopt it. They are also being told that having the Code badge will help them to stand out.

But if the aim is universal adoption, then design professionals could eventually be in a situation where there is nothing to distinguish between manufacturers – which is not really any different to the situation now, where nobody has a CCPI-style accreditation.

In that case, the determining factor will remain your individual experience of interacting with a manufacturer, and whether you feel confidence in that manufacturer and understand what their product offers.

At present, we would anticipate the biggest visible difference being that product information – especially in written form – is likely to be presented in a different way. Exactly how different will depend on each individual manufacturer and their current approach to providing information. But will manufacturers need to be accredited in order to do better?

How is Polyfoam XPS responding to the CCPI proposals?

Like any responsible manufacturer, Polyfoam XPS is always looking for opportunities to improve. We have used the consultation version of the CCPI to start assessing our internal processes, examining the flow of information through different departments and the content of published materials.

Since there is no detail about how CCPI accreditation will be assessed, at this stage we can only identify areas where we feel we may not meet all of the essential elements of a particular clause of the Code. In that sense, the exercise has already proved useful, and will ensure we continue to provide product information to a high standard.

Multiple factors will dictate whether this translates into a formal assessment against the Code, however.

What is next for the CCPI?

The industry is awaiting a report on the consultation response, followed by what changes the MIG will make to the CCPI before putting it into practice.

There are plenty of examples where ‘having a badge’ is demonstrably a good thing, and designers and specifiers respond to it. But there are also examples of schemes and accreditations that, however well intentioned, simply do not resonate with the intended audience. In such a situation, it becomes hard to justify financial resource for a scheme or accreditation with no obvious demand.

When that occurs, we can only continue to trust in the integrity of our processes and ensure that the design professionals we interact with continue to receive the benefit of our ethos, even if there is no ‘badge’ with which to ‘prove’ ourselves.

While there is undoubtedly support for the draft version CCPI, it’s not clear whether this is mainly from people and organisations who are closely following its progress because they are aware of it and already responding to the idea positively. There are also justified questions and concerns, which the consultation will need to answer.

The real acid test, however, will be acceptance from product information users. For manufacturers to adopt the CCPI badge over the long-term, there will need to be demand for it. And product information users will especially need to be willing to notice and respond to possible breaches, including engaging with the infrastructure that is set up to support monitoring and enforcement.

About Polyfoam XPS

You can read more about Polyfoam XPS here. You will also find information about our complete range of products, and downloads such as technical documentation and product certification. We also regularly discuss industry issues and product performance in our blog.

For any questions regarding the product information we provide, to find out more about the CCPI and how we are engaging with it, or to discuss how extruded polystyrene insulation could benefit your current project, contact us.



Polyfoam XPS has launched a new email newsletter to share information about construction products and standards, and to highlight useful resources for designers and specifiers.

‘The Build-Up’ arrives in email inboxes on the last Friday of every month, and is free to subscribe to. Each issue is also subsequently published in our News & Blog section of this site.

The short, easily digestible email highlights books, podcasts, magazines and other construction-related resources that can help designers and specifiers to achieve their project goals. It also includes a selection of inspiring news articles that readers may have missed elsewhere.

“We wanted to create something that aligned with our values of providing high quality insulation products and technical services,” explained Rob Firman, Technical and Specification Manager at Polyfoam XPS.

“As an insulation material, extruded polystyrene is robust and provides reliable long-term performance. Achieving quality in the design of construction projects, and ensuring that quality and performance translates to site, is essential for our industry to contribute to a sustainable future.”

Subscribe to ‘The Build-Up’ here and for a taste of the newsletter’s format and content, see this blog post version of the first issue, sent out in early 2021.

For any queries relating to Polyfoam XPS, our newsletter, or extruded polystyrene generally, contact us.