• Insulation that doesn’t work shouldn’t be called insulation

    Ecomerchant explains why this matters

    For 20 years we (Ecomerchant) have focussed on sourcing the best materials to build energy efficient, healthy, and sustainable buildings. We want to reduce environmental impact be it pollution, waste, embodied energy or toxic ingredients in everything we do, its part of our DNA.

    We haven’t been around this long by accident, natural materials such as wood are as old as building itself, proven over centuries, renewable and robust many natural products are popular because they are proven to work. Some of the most modern low energy buildings are made from natural materials, these aren’t mud huts but cutting-edge contemporary designs fit for our modern age. The processes used turn natural raw materials into performance products like insulation are some of the most sophisticated technologies in construction today.

    A good example of modern design built using a timber frame and wood fibre insulation this home offers high levels of comfort and ultra-low running costs

    Building technology doesn’t need to find chemically engineered, synthetic solutions to most building problems, most of them are solved in simpler more practical ways by adapting the inherent features of naturally occurring raw materials.

    Human beings and trees were not born in space, and are not designed to live in alien surroundings. The materials which are the most natural and most ancient in our buildings are the materials which we have evolved with and which are the best for us and for construction. Nature works by building up and breaking down; these natural cycles, sometimes over millennia, include robust and long lasting materials like wood but nature eventually welcomes them back by providing a mechanism for them to be recycled back into the system without causing adverse impacts on the wider environment. In short, all natural products are a food of some description. The same is not true of man-made synthetic materials like plastic or petrochemical-derived products. Nature has not had time to develop a coping mechanism so they persist often with alarming consequences. These materials require their own closed-loop recycling system, the problem is that we haven’t created that either so they inevitably escape into the natural cycle where they cause harm.

    We are most comfortable in buildings that don’t adversely affect the environment (this also includes the consequences of production and disposal of the materials used) or our health and we can all measure a reduction in the need for fossil-based fuels through our energy bills.

    The UK home insulation market alone is huge worth over £800 million of this a staggeringly small amount is made up of natural insulation products– probably less than 1%. The rest is largely manmade and so sits outside the natural cycle of re-absorption and re-purposing by nature.

    Accurate figures are hard to come by but there is one common factor we observe, natural insulation products are growing their market share. Insulation is an eponymous term as it is by definition an insulator, typically viewed in this country as a protector against cold.

    As public understanding of environmental concerns has re-orientated how products are sold and marketed we have seen moves by manufacturers of synthetic insulation materials to ‘shoehorn’ in green claims about what their products contain and this has made people wonder what was in there before that was so bad for us.

    Building Regulations should be the start point for design, not the end

    All insulation products, no matter what they are made from, reduce greenhouse gas emissions by reducing demand for heat (or cold) so all have a form of inherent 'eco' credentials, but as this applies to all insulation the principle difference between types of insulation boil down to suitability for the intended application, stated efficiency in terms of capacity, embodied energy and toxicity, and this is what has made manufacturers re-align their marketing to reflect these concerns into a new way of re-describing existing products.

    When choosing insulation its worth remembering that there is a significant difference between being 'designed' and being 'compliant', within UK domestic construction there is a tendency to focus on the latter especially when it comes to the building shell, this leads to a 'lowest common denominator' effect, a subject on which we have written about many times. A tendency to deliver only compliance can exclude beneficial features and expose us to unwelcome consequential problems. This also assumes that the level of compliance achieved will deliver the required performance and levels of comfort, which it can fail to do,  for example, we have all experienced over hot 'rooms in the roof', compliant yes, but comfortable no, an overhot room can be unusable. Designing and specifying materials should take into account all possible features and benefits not simply compliance, this also helps mitigate cost differences as you only end up paying for delivered performance.

    Insulation is capable of offering 10 key features – all of which are valuable in terms of building performance, installation and occupant comfort. perhaps you should be asking how many of these things your insulation can do.

    1. Insulates against cold or heat – these are the thermal benefits needed to create a comfortable internal environment and reduce energy bills
    2. Reduces sound – has acoustic properties – this helps create a better living environment. Some products are better than others.
    3. Buffers moisture – helps protect against structural damage, mould, fungal growth etc. This is a key part of healthy living, plus it protects your most expensive asset against repair and maintenance costs and keeping its value
    4. Reduces heat transfer by its mass (how much of it there is) especially true for ‘room in the roof’ and timber frame or lightweight construction, stopping excessive heat transfer requires more stuff in the insulation something that is inherent in all wood fibre products.
    5. Is simple and easy to fit – better fit equals less air movement equals higher efficiency. Badly fitted insulation doesn’t work, really badly fitted insulation is near useless, in other words badly fitted insulation is not insulation it’s just ‘stuff in a building’
    6. Fire: - almost all insulation has a similar fire rating, the key difference is that natural insulation is better at resisting the spread of fire than many synthetic options it also does not give off toxic fumes when burnt.
    7. Does not pollute or have the potential to pollute – no off-gassing- no toxic emissions – no concerns for asthmatics, or sensitised people and no health issues for installers
    8. No waste issues; can be recycled or reused without specialist mechanisms which carry a cost.
    9. Works at the same level over many years – doesn’t crumble, collapse, degrade or deteriorate and so lose its performance we have all encountered insulation that has failed in lofts walls and floors when we renovate or buy a property that needs updating, natural insulation is long lasting and doesn’t degrade.
    10. Meet or exceed the requirements of the Building Regulations. Remember Building Regulations are a minimum standard and do not require many of the above benefits to be met, except U value as a measure of conductivity – point 1. - be careful you don’t just choose an insulation that passes Regs, pick one that meets your needs, after all, they ALL have to meet the minimum standard so anything else is a bonus!


    1. Bonus Point. Choosing natural insulation can often eliminate the use of other materials such as membranes or boards so saving money and simplifying construction, after all, why take two products on to a building site when you can take one.

    Most natural insulation will deliver all the above.

    It’s a short step from this list to consider a genuinely natural product as long as it does the same job and is more or less the same price as a synthetic option. Never forget that bad insulation (insulation that is not fit-for-purpose usually cheaper, entry-level products made to a price) or badly chosen insulation is ‘not insulation at all’ if it doesn’t work reliably over many years it's just a waste of money.

    Our customers have shown us that they ‘get it’ they know that natural insulation can do everything a synthetic one can do but with more benefits and fewer unwelcome associated issues such as waste, embodied energy or giving off toxic fumes when burnt.

    Wood fibre boards can be safely left exposed to the elements for up to 6 weeks with no loss of performance. They may also remove the need for a roofing membrane.

    This change in the market explains why natural insulation is being specified and used more and more in areas previously the sole domain of the big insulation manufacturers, it works, this is a trend that we only see increasing.

    Most of the market growth is driven by customers wanting healthier products that function on a number of levels and compliment the higher performance being designed into modern buildings.

    Terms such as breathable and airtight have created awareness that natural products have multiple and consequential benefits plus they do not degrade or pollute the environment. Our modern-day focus on well-being and health have caused many to question the provenance of materials they have to live with, manufacturers claims are under scrutiny and viewed less plausibly than before and the consequential effects on our environment made by our choices now form a key part of the decision making process.

    It appears that the time for natural insulation materials is now and rather ironically the main driver is not the fact that they are natural it is often a performance and health-driven choice reinforced by the additional benefits they bring.

    How we help you

    Every home and every installation will be different but the methodology for calculating how much insulation is required, how it will perform and what type you need is a well-trodden path for our experts.

    If you are unsure or need a hand figuring out what you want, just call us and ask for help. This is what we do day in day out. Our manufacturer partners and our team will always be able to help you to work out what is the best available option for your particular job.

    If you know what you need then why not buy online you can shop when you want, all our products are delivered directly to you from stock.

    Our commitment to you is to only sell natural insulation products.

    How we can save you money. We are the only supplier of Steico insulation products to sell by the individual board or pack meaning we can keep unnecessary waste to a minimum. All our Steico products are priced individually by the board or pack (for Flex), buying online couldn’t be easier, just one click and the goods are on their way, just when you need them and no need to waste or store any surplus.

    If you need help please call and ask, we are here to help just call 01793 847 444 or email  and we will do the work for you.

    Wood fibre boards - product links

    Download our installation guide

    Steico Sarking and Sheathing boards Installation Instructions

  • Why would you incorporate a gaping hole the size of an ATM in your building shell?

    The answer to the question is 'because that's what the regulations allow and as many people regard the building regulations as a target standard that's what most people do.' 

    Current building regulations stipulate a minimum air leakage rate to be no more than 10m3/hr/m2, in the example below you can see that by comparison to Passive standard this equates to leaving an open hole in the building fabric equivalent in size to a typical a cash machine, whereas the Passive standard this hole size would be reduced to the size of a credit card.

    Obviously, people do not leave a single gaping hole but the equivalent size will be distributed over the whole building which means that the energy efficiency is stripped away by the movement of air through the building fabric especially the insulation. This is why airtightness matters and sits at the core of improved energy efficiency.

    What is Airtightness?

    Often we are asked what the term airtightness means.   Airtightness primarily focuses on the elimination of all unintended gaps and cracks on the external envelope of the building.  Airtightness is an essential part of creating a healthy, comfortable, energy-efficient living environment.  In contrast, air leakage is where leaks occur due to gaps and cracks that should not be there in the first place.  This can account for up to 50% of all heat losses through the external envelope of a building.  There are many factors which can cause air leakage such as poor build design, poor workmanship, or indeed the inappropriate use of materials.   It is important to remember that an airtight building does not mean it is hermetically sealed, rather it means that the air leakage has been reduced to a minimum.

    What role does ventilation play in airtightness?

    Ventilation is crucial in all buildings, not just airtight ones.  It is key to construct buildings which are both airtight and gap-free and then introduce a designed and controlled ventilation system which ensures that adequate fresh air is supplied to meet the needs of the occupants.

    Can I not just add more Insulation?

    Insulation requires high levels of airtightness to perform.  This can be explained by the "woolly jumper" effect.  Imagine going hill walking and you only wear a single layer then the wind blows through the woolly jumper quite easily.  However, if you apply a light windshield over the single layer it has a dramatic impact as it reduces air movement through the jumper and consequently, the woolly jumper insulates much better

    Therefore, for insulation in a building to perform it needs to be protected against air movement on both sides

    1 - on the outside protecting against wind by using a windtight external membrane




    2 - On the inside protecting against the hot air penetrating through it creating air movement through the insulation by using an airtight membrane

    Short Video -  Intelligent Airtightness Explained

    What are the benefits of airtightness?

    1. Reduced heating costs
    2. Improved health - substances which can provoke allergies can be carried into a building via air leakage - air coming from outside in or from within the building fabric itself
    3. Improved building durability - Airtightness protects the building fabric against damage due to moisture-laden air leaking into the building envelope and condensing
    4. Reduced callbacks - Airtightness focuses on build quality and quality workmanship
    5. Improved comfort levels - Airtightness is a key component in reducing overheating in summer and insulating better in winter
    6. Improved Acoustics - Air is a very effective medium for transporting sound.  Higher levels of airtightness means more effective reduction of sound transfer

    What steps can I follow to achieve high levels of airtightness?

    1. Design for airtightness - ensure the architect designs the building with key airtightness details in mind.  Keep it simple with the details
    2. Build for airtightness - Now that it is designed correctly, ensure all personnel who interact with the airtightness layer are trained and install products correctly.  Workmanship can be validated with a WINCON test.
    3. Test for airtightness - We can only understand how something is performing by attaching a metric to it, airtightness is no different.  Blower door test should be carried out to measure the airtightness.


    Airtightness - The Facts

    On average we spend up to 90% of our time indoors - it makes sense to make this environment as stable and comfortable as possible, free from any draught and cold spots.

    Based on the envelope area of a 1,900 square foot certified Passive House If built just to building regulations (a leakage rate 10m3/hr/m2) the equivalent size hole in the building once everything has been sealed up would be approximately 440 x 440mm.  Whereas what was achieved on this Passivhaus was a leakage area that is 10 times smaller at just 44 x 44mm

    To put this leakage area into perspective, if a building was built to the backstop allowable leakage rate for building regulations, a hole in the wall the size of a typical ATM machine would still be an allowable leakage area whereas for an extremely airtight would only have a leakage area equivalent to that of a credit card.















    This article is an abridged version of an original article published by By Niall Crosson, Senior Engineer, MEng Sc, BTECH, MIEI, CEPHC  in June 2017

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  • Should tradespeople know about airtightness?

    Achieving a reasonable level of airtightness is important for the energy efficiency of dwellings and the comfort of occupants. The benefits of improved insulation levels and more energy efficient heating systems are lost if warm air can leak out of a building and cold air can leak in energy, leaking energy is leaking money.
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    In the course of our day to day business we encounter plenty of customers, builders and trades who find U values a little confusing especially when it comes to understanding what the U value actually means and how it will affect or benefit the performance of a building, so we have compiled a brief 'U-Value for dummies' style explanation to help.
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