31 Comments

*Taps the sign*

"Housing shortages are a function of land use and construction permitting policies, period."

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Land use and building permitting policies and processes must improve, AND they are NOT the biggest constraint on supply. Lots of local governments approve way more housing projects than are ever built. The biggest supply constraint is boots on the ground. Demand for construction labour far outstrips demand. The biggest argument for mass timber mid/high rise is labour productivity. A high tech manufacturing plant and onsite assembly team can use 50% less FTEs than an onsite project. We need to move a big share of all construction into high tech manufacturing plants -- wood frame single family and low rise up to six storey and mass timber 7-18 storey.

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You're probably about the 13,578,024th person to say we need to figure out prefabrication, haha. No offense meant, but this is a long-standing idea and everyone, myself included, has their own favored model for it.

It just *never* pencils out to the extent necessary to be transformative. Precast concrete can shave 10% off the cost of certain structural or cladding systems, in narrow circumstances. Panelized light timber systems sometimes used in Central Europe for housing seem are highly path-dependent and are not, to my knowledge, either cheaper or faster overall for single-family homes than the American "frame on-site with extensive powertool use" model.

What you're proposing for mass timber is not dissimilar to off-site partial assembly of steel framing and cladding systems, which almost never works, that I've heard of.

Claiming, off the cuff, that you can use 50% fewer FTEs using a prefabricated system is something that I'm gonna need strong real-world documentation in order to believe.

And even if that's true of the structural system, it's still not true of interior fit-out and MEP systems, which take far longer to install than just framing the structure.

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You talk to a lot of people (and keep good stats). It is true offsite/prefab is like nuclear fusion. The best hope for multiple priorities and only 10 years away...always. Offsite, however, has moved from innovation to early adoption to early majority in some parts of the world.

It is a large, sometimes majority and growing share in most Nordic and Germanic countries for single family and multi-family is rapidly growing. Singapore too. Shrinking labour force is just one of the drivers.

There are a lot of policy and practice barriers that have to be overcome to simply level the playing field for offsite to allow them to be competitive. Many technology disruptions are like this: EVs, solar PV, even personal computers.... We should level the playing field and industry will figure it out.

While there are compelling arguments for steel and concrete offsite, embodied carbon is high.

As you point out, mass timber is resource intensive and forests have declining and volatile yields due to insect infestations, wildfire and over harvesting so it would be foolhardy to overly rely on mass timber. Wood frame makes sense for ≤6 storeys. We should be embracing a diverse palette of sustainable, low embodied carbon materials: recycled plastic siding, recycled tire roofing, waste wood/crop residue insulation, and new cement/cement-like composites.

This could be driven with a low-embodied carbon performance target with sustainable building materials. Leading jurisdictions have variations of this.

The 50% reduction in FTEs is happening under the best policy and practice conditions. In a defensible 2020 offsite assessment, Scotland -- most advanced in UK -- found a 16% reduction in labour requirements relative to on-site jurisdiction wide. Scotland also found the # of housing units per employee per year across 13 offsite manufacturers rose from 4.8 in 2008 to 6.4 in 2018. This is expected to rise to 6.8 in 2023. This underscores the importance of continuous policy and practice innovation in public and private sector to maximize benefits. https://tinyurl.com/wuvmpv2u

As someone with your broad construction interests, thought you would have a big interest in offsite manufacturing innovation. Cars, planes, appliances, electronics... are not built in backyards and runways, they are all built offsite. Offsite construction innovation is not new. Many Roman forts were built offsite. The Carthaginians -- who fought head on head for supremacy around the Mediterranean against the Romans dominated the seas because ship design and labour efficiency/construction speed was so superior due to smart offsite manufacturing. The tides changed when the Romans found a Carthaganian ship wreck and reverse engineered it. If the Romans didn't luck into offsite ship construction, the world would likely be a very different place.

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“As someone with your broad construction interests, thought you would have a big interest in offsite manufacturing innovation.”

You mistake “lack of trust” for “lack of interest.” I have enough interest and industry knowledge to have long since discounted the armchair theorists’ statements heavily.

By way of example, I’ll briefly pick apart your cited source… let’s look at its first case study: 16 1-bedroom apartments, 24 2-bedroom homes, and 8 3-bedroom homes at a construction cost of 5.3 million Pounds.

Being generous, given the nature of British per capita housing area, let’s say 700 sqf, 1000 sqf, and 1500 sqf, respectively, for a total floor area around 50,000 sqf for around US$6.7 million in 2017. That’s about US$135 per square foot in 2017 dollars.

I can currently (in 2024) construct a single family home for around US$120-160 per square foot doing everything on site. Less for townhomes or low-rise apartments. This is with material prices close to 70% higher than in 2017 and with American construction labor paid rather better than British.

I have yet to see a scrap of evidence that panelized light timber methods make any economic sense in the US, and have seen plenty of evidence that steel off-site assembly, which would be most similar to mass timber, is a complete and utter shitshow. Precast concrete does some things very well, especially in projects where site space is at a premium and time on-site is much more important than material and assembly lead times, but the cost advantages are far from dramatic.

I admit to being unclear why you think offsite methods are dramatically disadvantaged, that we need to “level the playing field,” though.

Meanwhile, a 2500 sq ft twin which costs US$300,000 to build in inner suburban Philadelphia or US$425,000 in lower Long Island sells for $650,000 in the former and $1.2 million in the latter.

This is a land use problem, full stop.

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Here in the western US, our parched throats beg to differ.

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You can credibly make that claim if and when 70-80% of your water use is *not* due to gross mispricing of agricultural water rights, not at present.

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Are termites an issue for mass lumber buildings?

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Will any single policy solve the housing crisis? Seems like the answer would be no. Instead there is a huge thicket of barriers that need to be worked through.

For example, I’ve heard the benefits of Europe only requiring 1 staircase apartment buildings in situations where the US uses 2. That is enabled by more use of concrete, which brings fire safety that can then be used in laxer layout requirements. This particular policy wouldn’t enable that, but seems like there are more ways to “spend” mass timber fire safety benefits over soft wood than just taller buildings. The point is these things interact and improvements on one side (materials) can help another (flexible building codes).

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As I just learned a week ago, five-over-ones are called that because they're Type V construction over Type I construction. Some of them are six stories over one, or four over one, or sometimes five over two, but they're all still five-over-ones because of the construction type.

Really, the mass timber on concrete podium construction should be called "four-over-one", even though mass timber makes it easier to go more than six stories up.

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Your main point is absolutely correct, however, considering that mass timber, as well as advanced light timber products can substantially reduce on site labor costs, their potential may lie more in facilitating construction in areas with the most severe housing shortages, since those areas necessarily have higher labor costs. So, as you say, potentially very useful, despite not “unlocking a solution to the house in crisis.”

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Also minimizing the amount of on site construction is one way to minimize prevailing wage requirements in places like California, which has been attached to key upzoning bills, but making them unprofitable

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Does moving to mass timber improve the weak productivity growth problem in the construction sector?

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See my comments above. This is the single most important reasons for transitioning to mass timber in 7-18 storey construction. Mass timber construction is inherently further along the continuum of offsite construction. We need to transition a large share of building construction offsite where we can double labour productivity. This is for wood frame (single family to six storey) and mid rise mass timber.

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Lots of v good points. The single most important point on supply and affordability is omitted. The biggest short and long term housing supply constraint, and a growing driver of rising cost is boots on the ground. Demand for construction labour far outstrips demand. This dynamic is part of broader trend impacting many sectors: health care, education, retail… Older workers are retiring. Demand for new workers and additional services outstrips recruitment.

The biggest argument for mass timber mid/high rise is labour productivity. A high-tech manufacturing plant and efficient onsite assembly team can use up to 50% less FTEs than a traditional onsite project. We need to move a big share of all construction into high tech manufacturing plants -- wood frame single family and low rise up to six storey and mass timber 7-18 storey.

Mass Timber is simply a pillar. As Peter mentions, there are compelling reasons to use wood frame. The foundation is fundamentally offsite construction. MT construction inherently is further along the offsite continuum.

ONE of the BIG offsite construction efficiency improvements is the potential for simultaneously manufacturing a building at the same time as excavation/foundation is underway. This, in and of itself, can cut completion schedules as much as 25%. A big challenge is that many local governments don’t allow this, increasing cost and construction time. Permitting innovations are one of many policies and practices that need to be updated to allow the mainstreaming of offsite construction.

First time mass timber or offsite wood frame projects are almost always going to be more costly. Developers who have fine tuned their systems (manufacturers, design professionals, general contractors, procurement processes, innovative local governments…), are delivering projects at lower costs.

The first mass consumer computer – the Apple Lisa – was $10k US in 1983 (about 30k in today’s dollar). When they were first introduced into offices, they slowed us down until we figured out new systems. As manufacturing scaled, costs plummeted.

We have to do the same for offsite MT and wood frame construction.

(The quality and cost control of a high-tech manufacturing plant is also the only way to scale near net zero new construction industry-wide.)

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“A big challenge is that many local governments don’t allow this, increasing cost and construction time.”

This is… completely untrue?

It’s incredibly routine to work on steel or precast fabrication during, or even starting prior to, beginning groundworks and pouring a foundation.

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Why would mass timber be catching on now, rather than ~a hundred years ago when people first started mass producing tall buildings? Has some new technology enabled it?

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Several reasons. A big one is fire codes.

Fire codes prevented building in wood in taller than 2 storeys in much of Europe until the 1990s, and greater than 4-6 storeys in N America until the 2010s. Fire protection measures have evolved (sprinklers, firewalls between units, tall ladders....). As the article states, we can build in wood frame up to 6 storeys in most of N America and now the Int Building Code, adopted by many jurisdictions, permits mass timber construction up to 18 storeys.

There are many policies and practices designed for traditional onsite construction that need to be amended to allow offsite wood construction (wood frame and mass timber) to be mainstreamed.

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What about countries in Europe that have longer history of mass timber? are they cheaper because they are being compared to brick or concrete buildings rather than light wood framed ones? or do they have the same cost pressures that have kept back mass adoption

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Hi from a senior lady who worked as a secretary for a statistician and as an office manager in the timber industry in Portland OR in the 1970's. I worked for Pope & Talbot and Fibrex & Shipping. My response has nothing to do with so-called sustainability or climate or carbon. No. Rather, I'm appalled and shocked by this 21st century trend to use timber without a peep of recognition for past harms done to said industry and the people who worked hard there. Lives, livelihoods, were unsustainable, and I can use that term in its original sense. The outrageous behavior by the anarchists, "eco-terrorists," who harassed the industry year in and year out is unforgivable. All for the spotted owl propaganda.

California Fires Analysis: Trees That Burned From THE INSIDE

Are you aware that a California arborist studied fire-damaged forests and discovered that the trees burned from the inside? He has made a few video reports and interviews. Why does this happen? He surmises that the trees are taking up metals FROM THE THE SOIL. He also posits that the cause of these fires that turned homes into dust, were caused by some kind of electromagnetic pulse, a pulse which charged metal, the metal inside the trees. The leaves didn't burn.

Where do those metals in the soil come from? From the nanoparticles sprayed on the entire planet from military jets, that's where. They are aluminum, strontium, graphene, etc. What does that have to do with your "mass timber" topic? Think on it. If housing is constructed with wood that is infused with metals, and the directed energy weapons target those buildings - poof!

"If Houses Burn But Trees Do Not, Is It Really A Forest Fire?"

https://rumble.com/v3zvx50-if-houses-burn-but-trees-do-not-is-it-really-a-forest-fire.html

"Robert Brame, a forensic arborist, who has analyzed 38 California fires and has come up with hundreds of photographic evidence of IMPOSSIBLE normal fire behavior. "

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As someone who lives in Oregon, where long term forestry practices have been environmentally and economically problematic (but always sold as green), I am concerned that the positive environmental impacts of higher harvests may be overstated. This article, https://e360.yale.edu/features/as-mass-timber-takes-off-how-green-is-this-new-building-material, does nothing to quell my concerns.

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Land use and building permitting policies and processes must improve, AND they are NOT the biggest constraint on supply. Lots of local governments approve way more housing projects than are ever built. The biggest supply constraint is boots on the ground. Demand for construction labour far outstrips demand. The biggest argument for mass timber mid/high rise is labour productivity. A high tech manufacturing plant and onsite assembly team can use 50% less FTEs than an onsite project. We need to move a big share of all construction into high tech manufacturing plants -- wood frame single family and low rise up to six storey and mass timber 7-18 storey.

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Shouldn't the cost comparison with a truss also include the gypsum/insulation/etc. needed to achieve the required fire rating? Or alternatively, it seems like you could introduce some voids into the center of the CLT structure to save on materials (at the risk of negating the fire safety benefits).

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Great read - Born in BC I have a deep love for the province and have watched them struggle with affordable housing, old growth, maintain environmental roots.

This wasn't even on my radar - Thanks for enlightening me.

I've have recently become very interested in 3D printed homes and building, but permitting, long standing corruption in real estate/constructions, and outdated thinking might be a huge obstacle.

Canada added about 5 million people just recently without investments in housing.

https://www.cbsnews.com/news/3d-printing-on-earth-and-moon-60-minutes/

https://realestate.usnews.com/real-estate/articles/are-3d-printed-homes-the-future-of-housing

https://www.cnn.com/style/texas-3d-printed-home-icon/index.html

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> It sequesters a huge amount of carbon because of the volume of wood it uses, so it's far less carbon-intensive than concrete or steel.

This reads as facially preposterous. Does this take in to account the lifetime of carbon absorption that has been truncated to produce said lumber?

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Pine sequesters carbon most rapidly as it grows to the size needed for commercial exploitation and levels off pretty rapidly thereafter because its growth slows markedly, so this statement makes complete sense. Leaving pine trees in the ground does very little for carbon sequestration in the long run relative to commercial forestry or reforestation with balanced, native-led ecosystems, both of which are needed.

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Well, I am glad that I hedged with my skepticism. Thanks for the informative response.

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If my rough calculations are right the lumber in a 12,000 sq ft. house would displace about 60,000 miles driven by the average car. Go up five stories and you've absorbed the carbon emitted by the lifetime of one car (ish---300,000 miles). Wondering if EVs are a better strategy than mass lumber construction (considering goosing lumber construction would send prices through the roof).

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The carbon actively sequestered is only a small part of the net benefit, because the counterfactual isn't "no building," it's "steel and concrete building of similar size and purpose," and the structural system of that hypothetical building has a massive positive carbon footprint instead of a small negative one.

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If you have a choice between electrifying cars and replacing concrete construction with mass timber, then maybe your calculation suggests that the former is better than the latter.

But I don't think that these two types of policy trade off against each other.

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