Can “Plywood on Steroids” be the Answer & Save the Planet, Too?

by Peter Quince on 2018-01-30 11:09am

It’s a classic case of good news/bad news. Michigan (especially Detroit) was hit hard by the 2007-2008 recession, with car manufacturing and construction hit hardest. Unemployment hit 15%. Detroit, once a city of 2 million, dropped to 700,000.

But – good news! Michigan has rebounded, big time. Detroit is undergoing a renaissance, with the Little Caesars Arena just part of the rebirth. Construction jobs grew in 2016 in Detroit at the 7th highest rate in the nation. The auto industry is thriving, unemployment under 5% is among the lowest in the nation, and population is growing, not shrinking. The “millennial” generation overwhelmingly prefers city living, with Detroit among the 4 fastest growing in this age range, helping fuel a construction boom. Meanwhile, older homes throughout the Wolverine State (averaging older than 50 years) beg to be replaced with homes more suited to 21st century tastes. Pent-up demand is massive.

But – bad news! The industry can’t meet the demand. For example, although the number of permits have grown since 2009 from 6,392 to 16,000, the Home Builder’s Association of Michigan (HBAM) estimates 30,000 new homes a year are needed to meet demand. A 2017 study by the HBAM points to three reasons:

  1. A lack of skilled home building workers (“Another pressing issue is the lack of skilled workers. This is especially notable in a state where online classes are available to help people prepare to earn their Michigan State Builders License”)

  2. Not enough places to build new, affordable homes

  3. An overly complex system of government regulations (“regulatory delays and the lack of property available for new home building has led to severe challenges”)

By now, everyone in construction knows there are too few skilled worker around. Many of the more than 250,000 in construction trades before 2008 left and and didn’t return. Meanwhile, fewer young people go into building trades, so that there are now about 170,000 who work in construction, and the industry can’t keep up with demand, which then inflates housing prices. The cost of materials keeps rising, as well. The HBAM estimated, for example, that lumber costs alone for the typical house rose $3,600 in the first half of 2017.

What if there was a new, amazing, space-age, cutting-edge construction technology that might meet these challenges and Help Save the Planet, too? What if the most advanced building material was…wood.

That’s right. It’s like the best friend in a movie who, when the dream romance fizzles, was There All Along. Good old wood. But not your father’s two-by-four highly flammable “balloon” frames. It’s called “Cross-Laminated Timber”, but like any high-tech product, it goes by the acronym CLT. It’s been called “plywood on steroids”. CLT is a prefabricated wood panel consisting of 3, 5, or 7 layers of kiln-dried lumber boards stacked in alternating directions, bonded with structural adhesives. The reason for the odd number of layers is so the outer layers face the same direction. Often called “as strong as steel”, it’s much lighter, with superior acoustic, fire, seismic, and thermal performance and uses the quality of wood being strong in the direction of the grain but weak in the cross direction by setting each layer perpendicular to the next so that it becomes strong in both directions.

It’s different from glued laminated timber (Glulam) which is used the same as any beam in traditional construction. CLT comes as a panel, cut to meet exact specifications, including door and window openings as well as (in some cases) HVAC and wiring pre-installed. The prefabrication uses computer-guided precision cutting, capable of making any shape within millimeters of the specs. Because it replaces the stud and beam “balloon” framework with a solid panel, vertical and horizontal stress is displaced across a broad area, enhancing its ability to be load-bearing. The result is a structural product that can be used to build roofs, flooring, and support a structure up to about 10 stories.

I know what you’re thinking – it’s wood, so it’ll burn easily. Because of its mass, it’s about as hard to ignite as a huge log plunked onto a fire and it tends to self-extinguish, but even if it doesn’t, it chars from the outside in, so it retains structural integrity even in a blazing inferno far longer than steel, which melts. For good measure, the IBC requires the exterior surface of CLT to be protected either by fire-retardant treated wood, gypsum board ½ inch or thicker, or another suitable noncombustible material.

Here’s how it can help solve Michigan’s skilled construction worker shortage: once the panels are shaped to the architect’s specs, the panels are essentially “building blocks”. A small crew without the kind of extensive training needed to become a carpenter can screw together the panels in relatively little time. A Popular Science article describes it as akin to assembling furniture: “The instructions are like Ikea but a little more straightforward.” The article goes on to cite a 9-story building with a CLT frame (and steel corners and connectors) completed by six men in 12 days.

What about the cost? The price point is a big issue. The taller the building, up to the inherent height limit of the technology (which generally means multi-family and commercial structures), the more sense CLT makes in terms of cost. Since it’s so much lighter than steel and concrete, it needs less of a foundation and is easier to handle, requiring a smaller crane. The labor cost savings are also substantial, since CLT is fast and easy to install and generates almost no waste on-site. Avoiding penalties for late completion alone can make it worthwhile and the finished product is superior in many ways. As the technology develops and assembly-line designs developed for private homes, it may move into that market as well.

I know what you’re thinking – how many forests will be cut down to make CLT? That’s the best part. Because it relies on layers of smaller beams, it can reduce waste by using odd-shaped, knotty timber that lumber mills would otherwise reject. A traditional two-by-four has to be milled from a single tree, has to be straight, and the wood wasted is substantial, all of which is so much less with CLT. And CLT is a carbon “sink”, since it takes CO2 from the atmosphere as a tree and sequesters it in the CLT, instead of decaying and releasing it back to the atmosphere. Get images of clear-cutting out of your head and instead think of vast crops of carbon-sequestering trees grown to be harvested and replaced immediately in a rotation of sustainable arboriculture.

Don’t forget, also, that concrete and steel are energy hogs, generating more than a ton of carbon dioxide to produce and transport per ton of steel or concrete. Wood, even given the additional processing of CLT, is far more environmentally friendly. Wood for Good (an industry initiative for sustainable wood construction) calculates that “a ton of bricks requires four times the amount of energy to produce as a ton of sawn softwood; concrete requires five times, steel 24 times, and aluminum 126 times. Wood also performs better: It is, for example, five times more insulative than concrete and 350 times more so than steel. That means less energy is needed to heat and cool a wood building.”

See! It’ll Save the Planet. CLT has been accepted in Europe for more than a decade. The 2015 Michigan Building Code (along with the 2015 IBC) got on board (no pun intended) and added Section 602.4.2 for CLT. As cities continue to need more housing for millennials and others, building upward is a way to make the most housing from the least amount of land, and CLT can be a big part of that.

Michigan, with its rich history of logging and of industrial innovation, could be well-positioned to make CLT a booming industry as well as an engine for faster construction with fewer workers. If we can find enough skilled workers.

Peter Quince has been making his living as a professional writer since 1978, most recently as a contributor with At Your Pace Online, an innovative online education company that offers pre-license and continuing education for Michigan Contractors, plumbing, electrical, & HVAC as well as for professionals in the real estate, insurance, Water Operators, mortgage loan origination, and tax preparer fields.