- braacus
- Oct 1, 2024
This website is intended to be a world-wide resource for AAC. But today's blog is going to expand upon the last post by focusing on a single area of the world: the USA, Canada, and the UK. In other words, the English-speaking north (apologies, Quebec). Their economic hegemony and importance in the world economy is obvious. So it's relevant to ask: why are they particularly resistant to using AAC when the entire rest of the world (where supply is available) embraces it?
The UK, same as Europe, embraced AAC in the post-WWII era. It is still available there. But as mentioned in the last post, its use in RAAC is not very popular right now, due to a combination of unrealistic expectations and AAC characteristics that impede detection of imminent RAAC failure. Media descriptions of these problems leave out important context that are approaching anti-AAC hysteria, and has now spread to Canada.
In the short term, anti-RAAC hysteria isn't likely to penetrate the US consumers because there really aren't any. Extensive forests of pine have made lumber the religion of construction in the US. But now its forests are proving finite, wood quality is diminishing, and lumber costs are increasing. The US' lack of experience with AAC means that potential consumers can confuse RAAC with AAC. It's not unreasonable to suggest that negative impressions from the US' English-speaking North neighbors will reduce interest in AAC.
I have included pictures of some of the world's most iconic bridges so that you can spot the trend. What are they all made of? Materials have specific uses. Metal is great for spans; concrete, not as much. Concrete is great when dealing with compression and shear. For spans, concrete has to be reinforced. What do the walls of buildings handle? Surprise! Compression and shear. RAAC, when used as flooring and ceiling, is about span. Forces in tension. Even so, it has done a superb job (see last post). But it is not the same as using AAC for structural walls.
The current miniscule AAC market in the US consists of fire walls (i.e., interior walls) and building claddings, both applications as panels. The cladding panels are typically 2 inches (5 cm) thick. Talk to any current producer, distributor, or builder of AAC in the US and they will tell you that this is the future of AAC in the US. Go ahead, try to find one with a different narrative. I dare you. You won't.
Is this 3-D chess or stupid optimism? How many firewalls does the US need? Can firewalls meet standards with other materials (yes.)? What does anyone with even 10 minutes of experience understand to be the most valid objection to using AAC when costs are equal or cheaper than the alternative material? It is the unaesthetic hairline cracks, which can become structural issues in (surprise) panels.
These cracks are almost always vertical, in the direction of the compression force. I'm not an engineer, so don't take my word for it, but I've been told they have little consequence for the strength of the wall because the force is travelling parallel to the crack. But if your panel is just cladding, it really doesn't matter since it's just hanging on to the side of your building. What's more important is that your wall look nice. Smooth. Not cracked. But I'm sure the experts know. There will never be any cracks and Americans will now fall in love with AAC. The will use it everywhere.
Or, some panels will crack. AAC will develop a reputation: "light weight is cheap." Sure, that's hypocritical considering Americans use plastic and foam everywhere (most of the lumber buildings are held together by glue [in the OSB] and tape [to prevent vapor penetration at seams]). But in thin sections, yes, AAC is brittle. Blocks absorb bullets but corners fall off if you look at them wrong. And Americans will never want to trust AAC in any use. And its use will vanish in the English-speaking north. It feels to this author like AAC is headed for ridicule, bans, and permanent disdain.
OK, so what? Who cares if these countries reject AAC, even when AAC makes the most sense? They are economic hegemonies and if their building infrastructure isn't using the product with the most value, that inefficiency is their own problem. Give the rest of the world a chance to do better. The lack of interest by some of the world's leading economies isn't slowing the spread of AAC elsewhere.
A "go your own way" attitude is very much aligned with the American worship of individual freedom. If the US chooses to ridicule scientists and China chooses to honor scientists, then they can't complain when American industry doesn't innovate and declines. Accept the consequences. As an American, I've always heard that this is the best way to learn. We call it "the school of hard knocks." I've found that in the real world, it's better to learn from the mistakes of others. Also, the challengers can cheer the struggles of the champion, but we have one world in which waste is waste. It is a defeat for us all.
The decades-long attempt to increase AAC market share is undeniably an unmitigated failure. Over 30 years, I have talked to end-consumers, as well as multiple producers, distributors, and builders. The latter have all assured me that their strategy is the best possible, and when they are barely hanging on or going under, they provide me a long list of forces that were beyond their control and almost made failure inevitable. A tacit admission that they recognized from the beginning that they were not living in reality, but, hey. They tried. Meanwhile, AAC expands everywhere else across the world.
Is the current strategy of firewalls and cladding panels the key to AAC market success in the English-speaking North? See you in 30 years.