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Off-cuts and scrap

Some of my favourite toys were those made for us by my dad from scrap timber that he had salvaged on construction sites. When we were very small, these were quite chunky wooden blocks, lovingly shaped and sanded, and as we got older, the blocks became smaller as we developed dexterity. Back in the 1960s, when my dad was a practising architect, building sites were notable for the lack of waste. The craftsmen had a very clear hierarchy - offcuts were pieces (of whatever material) that could be reused, and were safely stowed for just this purpose, and the "scrap" that my dad would collect for our toys was kept to a minimum.

This was facilitated by the manufacturers' sizing of materials and components, which had evolved over many decades, and in some trades, over centuries. For example, a standard brick was 3 x 4.5 x 9 inches - this facilitated a number of different "bonding" layouts, or ways of arranging the bricks in a wall.

Some of the more common brick bonds
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Some of these bonds were for structural reasons - Flemish and English bond have alternating bricks set at 90 degrees to the wall, creating a "tooth" that links the two leaves of the wall together. The 3 x 4.5 x 9 brick was perfect for this, with no cutting required. You could also set the brick on its side or vertically and have multiples that fitted exactly within the 9 inch length. At the ends of the wall, to get the bond established, you would need a half-brick (4.5 x 4.5 x 3 inch) or a "queen closer", a half-brick cut lengthwise. One of the first things I had to learn in bricklaying from an old-school craftsman was how to cut a half-brick neatly so that remaining half brick could be used later. These half-bricks would be carefully stacked, minimising waste and halving the effort of cutting.

When standard steel windows were introduced in the 1930s, their width was determined by the length of a standard brick, and the heights were calculated as a multiple of the brick's 3 inch height. In this way, two industries - steel and clay brick - were working in harmony to reduce waste on site. 

The challenge came in the mid-1960s in the UK, leading up to the introduction of the metric system in the construction industry in the early 1970s. This conversion in the UK was voluntary for industries, but there was pressure on the British steel manufacturing industry to change over to align with their trade partners in Europe.

One of the heavily thumbed books of my architectural education was the AJ Metric Handbook, first published in 1968. This had the sizes of a huge range of things, for example the standard dimensions of standard tennis courts, olympic swimming pools, soccer fields and the like. The first chapters (largely ignored by us student architects) are what really interest me here. Following a chapter on the metric system, there was a chapter on modularisation. What was being proposed was that all building materials and components should be based on a 300mm module, with all sizes based on multiples or simple fractions of this magic number (not surprisingly, a length very close to the imperial foot, which it was set to replace).

Likewise, spaces should also be designed on multiples of this module, a practice that had some traction in the 1970s and 1980s in office buildings and factories, with a dominance of steel components and modularised ceiling systems. However, the more "creative" architects (and here I am guilty), planned their buildings and spaces driven by other criteria, some based on proportioning systems such as le Corbusier's "Modulor" which was inspired by the Golden Section. 

The "Modulor" of le Corbusier
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As you can see in the diagram, this is based on a "standard human height", and each dimension evolved from this in the Golden Ratio which le Corbusier neatly relates to various human dimensions. Two things to note: his "standard human" is clearly some idealised male (Corb himself was quite short), so while the principle of designing ergonomically, to suit the human body, and to use a proportioning system associated with beauty in nature, the reality is less "universal" than was intended. More important to my argument is that his measurements have no relationship at all to the 300mm module that became the construction industry standard in many parts of the world.

As a side issue, the 300mm module did not fit comfortably with the standard brick size, which evolved over the centuries not just with great proportions that allowed for a multiplicity of bonds, but was also the perfect size, shape and weight for very efficient bricklaying. Many attempts were made to reconcile the needs of the bricklayers with the modularised 300mm and its simple fractions (eg 150mm, 100mm, 75mm) but the results were either too large to be held comfortably, too heavy, or too small such that the daily overall output volume of the bricklayers would be compromised. The result is that we have retained the 3 x 4.5 x 9 brick size, but "translated" into metric dimensions. Likewise, standard steel windows have retained their original sizes based on the imperial brick length and height.

The big crunch is that a building can either be designed on the 300mm module (great for a steel structure with aluminium windows and "contract" ceiling systems), or on the brick module, but the two do not comfortably combine, resulting in loads of "scrap" rather than the off-cuts that are reusable. Moreover, and the point I really want to make, is that building designers often just use whatever size they want, with no thought about standard sizes, leaving the problem of waste to the builder. Construction waste contributes around 40% of landfill waste globally, so it is time to start thinking of sustainable construction not just as buildings that use low carbon, green energy, and the like, but consider the more basic problem of waste first.

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