The only question to ask when buying building materials

Most of us are not trained to buy but we buy from people who are trained to sell….so we are always at a disadvantage, inevitably we often end up making assumptions and filling in gaps.  We succumb to advertising claims, we read reviews, we take people on trust, we buy what’s readily available in short we cut corners and don’t ask the right questions. We all seem to value convenience, maybe we don’t know what the right questions are…but there’s one question you can always ask that will get you closer to choosing the right material the first time.

Asking the right questions is important, not because all product manufacturers or merchants are charlatans hoping not to be uncovered but rather that the sheer amount of choice can be overwhelming. In any application there can be hundreds of viable options;  manufacturers work hard to distinguish their products from others, but without in-depth technical knowledge choosing can be a minefield. Most clients paying for a building will employ professionals to work on their behalf, they work for you and require a brief which can include broad requirements such as energy efficiency, indoor air quality and non-toxic materials the brief will orientate their choices made on your behalf. Choosing building materials is a combined effort but you need to get what you want and not just abdicate the decisions to others without some form of agreed context or understanding.

Put simply any benefit or feature of a product should be specifically relevant to your needs, it must have a tangible benefit. We choose a material because it appears to meet our needs, so put simply if it’s thicker, stronger or more flexible for example then you should ask the one important question which is ‘which means?’ and keep on asking it until you are sure of the suitability of the product, if the answers aren’t of any use to you then choose another product. This does leave the thorny issue of price but well come to that in a minute.

Back in the day when we could meet customers face to face, especially at trade shows, we were surprised how often we were asked questions that seem to lead nowhere in terms of matching performance, features and benefits, we seldom encountered the ‘which means?’ question or worse weren’t asked about more than one feature of a material or product but, guaranteed, the one thing everyone asked about was the price!

To illustrate the point at the last regional building show where we exhibited targeted at self-builders we were promoting natural building materials our stand had a large display of wood fibre insulation flexible batts and boards. During the show, we encountered the regular use of the ‘comparison question’ a frequently asked example was “how does rigid wood fibreboard compare with xxxxxx? - the customer referred to a well-known foil backed PIR board brand!.

You might think this is a simple question and in some respects, it is, however when asked like this it is anything but because it relies heavily on assumptions……assumptions that need to be correct; assumptions that would be tested by using the ‘which means?’ question.

We could have replied to anyone asking this question with a comparison question of our own such as “Tell me how does lino compare to carpet?” they are both floor coverings but that is where the comparison ends, the same applies to insulation. This form of loosely defined comparison question exposes an ‘assumption flaw’ when used to choose materials and needs to be followed up with the ‘which means?’ question to uncover exactly how suitable the product is for what you have in mind.

To help to find out if only asking a comparison question is a good way to choose a product,’ we decided to see if we could uncover some of the thinking behind the question and possibly a little of the psychology as well. So we ran a little sales experiment to try and find out some answers, we decided to test some assumptions on visitors to our stand; the assumptions we wanted to test were.…

  1. Price is often the principle buying motivator
  2. Performance is set by others, for example, Building Regulations, meeting Regs is often enough to select a product ergo customers tend not to set their own performance targets, making the ‘which means?’ answer ‘compliance’.
  3. All insulation is more or less the same
  4. Natural insulation is always more expensive than synthetic
  5. People don’t read manufacturer literature
  6. People don’t understand the quoted performance figures
  7. The most readily available materials are the best
  8. Customers assume that architects and builders build the best they can for their clients

In one exchange, when asked how Steico Special (a rigid wood fibre sarking board) compared to the price of a branded foil backed PIR board, we said (to test some of the assumptions) “its 3 times cheaper…does that matter?” Yes said the customer “we’ll be using the Steico product”. Not one question about where or how the insulation was to be used or if the Steico product would be suitable. Does this confirm assumption 1. Well…yes it does it also confirms assumption 3.

Steico Special Dry as a sarking board on a large flint built barn conversion in East Sussex

We told the slightly disappointed customer the real answer which is that we wouldn’t be able to tell them unless we had more information, for example, it depends which PIR board they were comparing it to (they weren't aware there were options) where it is being used on the building and specifically what performance criteria were they seeking to meet.

We also wanted to know if they had any personal preference about toxicity or environmental impact. In the end, we gave them the rule of thumb that to meet the same U value allow approximately 1.7 times the thickness when using wood fibre insulation. In this case, by using Steico Flex between the rafters and Steico Special Dry on the outside the cost uplift could have been around £6.00 per square metre to use wood fibre over a general-purpose PIR board at 100mm depth. But this is simply a price comparison, no allowance was made for performance, ease of installation, environmental and health benefits or disposal costs all factors that change the cost rather than the price.

As it turned out the price difference was much smaller than the customer had anticipated plus their house was a large extension to an existing much older building and the thermal, diffusivity and hygroscopic benefits were easy to explain and make relevant, and subsequently for them to attach a value to, when they asked the ‘which means?’ question they could attach a real value to the answers meaning the comparison was now based on performance and real benefits not the unit price at compliance only i.e. by only meeting building regs and not exceeding them.

The difference in performance between the two products provides the reason for the difference in price, what might appear to be a more expensive choice could be cheaper in reality, as the cheaper product doesn’t provide extra benefits. In this case, with a 140m2 roof, we were negotiating the cost-benefit of £840 within a total insulation material cost of around £7,500. To improve matters they could also lose around £300 in membrane costs (not needed with the wood fibreboard) bringing the price difference down to around £3.80 per square metre more for wood fibre over synthetic. They have since ordered wood fibre boards for their roof.

Part of the added value demonstrated by the ‘which means’ question is shown in the illustration below as you can see all the sections have the same U value of 0.13 (Building Regs 2010 New Dwellings) however a benefit or value provided by different construction methods is the phase shift,  a measure of how long it takes for the maximum temperature recorded on the outside of the structure to be recorded on the inside of the structure in hours,  this feature is not a part of the current Building Regulations. Simply changing the insulation extends the resistance to the passage of heat through the structure meaning its more comfortable inside. Wood fibre delays heat for twice as long as PIR and more against mineral wool and glass wool

The benefit of increased phase shift is best illustrated by rooms that are directly affected by solar gains, such as a room in the roof. Extending the phase shift will create a more comfortable space simply by extending the phase shift beyond the time the outside surface is exposed to a direct heat source, in this case, sunlight.

Always use the ‘which means?’ rule.

The ‘which means?’ rule is designed to give answers to any claim about a product feature. Try this one. One feature of Steico Special Dry shown in the technical data is described like this SHC= 2,100 J/ (kg * K)], an important feature but do you know what it means?

The answer is it is a measure of the Specific Heat Capacity of the material which is the amount of heat needed to raise the temperature of 1kg of the material by 1K (or by 1oC). A good insulator has a higher Specific Heat Capacity because it takes time to absorb more heat before it heats up (temperature rising) to transfer the heat. High Specific Heat Capacity is a feature of materials providing high levels of phase shift.

 In this case ‘using wood fibre gives a phase shift of 16 hours largely due to its high Specific Heat Capacity ’ which means’ that you end up with a useable, comfortable room at any time of the day or night and not a room that is stiflingly hot after a sunny day, particularly relevant if it’s a bedroom.

The ‘which means?’ rule is a very good way to cut through techno-speak, jargon and formulae that may make sense to others but have no meaning for you. What customers are interested in is what it gives them, not necessarily how it does it.

Once you have an understanding of the benefit brought by using a different insulation material then the comparison becomes much more realistic. With such understanding, the value can be attached eliminating comparisons that serve no useful purpose.

To sum up, this is broadly what we discovered and learnt about the assumptions we tested in our little ad hoc sales experiment.

Assumption: Price is the main buying motivation

Reality: Often this is where it starts, we acknowledge that price is important but it’s part of a value judgement, we encourage customers to eliminate erroneous comparisons and focus on applications where the benefits stack up in their favour. We also encourage customers to price in real performance benefits over and above compliance i.e. Building Regs

Assumption: Performance is set by others, for example, building regulations, meeting this is enough to select a product

Reality: The old chestnut, Building Regs are a minimum standard not a guarantee of performance or quality, we are constantly amazed at how many people get this but still default to Regs for large parts of the build. Again the value rule applies, use the ‘which means?’ test to expose the REAL benefit of any claim, pay for features that you will benefit from and don’t pay for benefits that you don’t need.

Assumption: All insulation is more or less the same

Reality: We can prove it isn’t, it’s always ‘horses for courses ‘no one type of insulation will be suitable for every job, expect to use a mix of insulation types.

Assumption: People don’t read manufacturer literature

Reality: If they do it’s often cursory and the reader may well not understand the implications or benefits anyway. Part of this conversation needs to be in plain English. Real areas of interest we experience from customers are handling (irritation etc.) ease of use, disposal, off-gassing, toxicity (what it’s made from) and occupant health. During the show, customers would continually play with the samples whilst we chatted,  we pointed out they wouldn’t do that with mineral wool or polyisocyanurate board (PIR) this was a clear illustration of the benign nature of many of these materials which immediately addressed some of the top concerns they have.

Assumption: People don’t understand the quoted performance figures

Reality: There are too many metrics, SI units and norms (BS, EN DIN for example). Information from different countries and testing bodies are complicated by differing national, local and international regulatory requirements, this can be a minefield it’s no wonder that the average builder and even architects can struggle to make any meaningful performance comparison. This needs a plain English approach. Always remember there can be a huge difference between compliance and performance. Good enough for Regs might not be good enough for you.

Assumption: The most readily available materials are the best

Reality: Considering insulation as a specific group of products their popularity is evidenced by their availability (indeed it may even be the other way round) but not their efficacy, often there isn’t any real supervision over their specification and installation. Trades make up a substantial sector of the market and little is done to offer a wider choice or explain any limitations to them so the same products get used ubiquitously often with no real understanding of their suitability.

The aim must be to make specification simple and clear, ditto installation hopefully we do our bit in helping customers broaden their options and making all our products easy to buy and readily available.

Assumption: Customers assume that architects and builders build the best they can for their clients.

Reality: This is nothing to do with questioning the skill of architects or builders, building projects are complex they rely on interconnected disciplines working together, however, if the client is not aware of options then they won’t necessarily ask, leaving the others to use either well established, commercially advantageous or just good enough solutions, which may be incompatible with the desired outcome. Better informed clients will demand better solutions, more demand will encourage more supply-side capacity, and crucially will move projects into using Building Regs as a start point, not the endpoint; fortunately, this appears to be where we are moving to.

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