Mass Timber Series Week 3: The Cost of Structural Systems in Buildings

What are the primary cost differences between mass timber and other commonly used structural systems, like concrete and steel?

Mass Timber 8
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Materials like mass timber, concrete and steel are commonly used to build structural systems, each with unique qualities that provide various benefits. In response, structural systems of distinct materials fluctuate in price. What is the central cost difference between assorting structural systems, and how can this deviation be explained?

Participate in the discussion with industry experts: @Nic_Wilson @Aitor_Arteta @tim_hanson @David_Stallcop @Igor_Adriaensen @David_Bagdy @Andrey_Tikhomirov @Neill_Gibson @ARNIE_DIDIER @Dusan_Milutinovic @Oleg_Semenov @Steve_Marshall @KayCee_Hallstrom @Jerry_Truex @Josh_Trayner @Franco_Piva @Bella_Carmelita_Carr

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This is definitely a question that needs to be posed to some engineering/designing firms in the Mass Timber arena who have made these comparisons on past projects.

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Hello MassTimber experts – as per @David_Stallcop 's comment, are there any such documents or studies that are for public distribution and can shared here?

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If it’s tedious to post publicly available documents on this topic in their entirety here, for whatever legit reason, perhaps the experts can share their findings and cost analysis from previous work, at a high level. @Nic_Wilson @Aitor_Arteta @tim_hanson @David_Stallcop @Igor_Adriaensen @David_Bagdy @Andrey_Tikhomirov @Neill_Gibson @ARNIE_DIDIER @Dusan_Milutinovic @Oleg_Semenov @Steve_Marshall @KayCee_Hallstrom @Jerry_Truex @Josh_Trayner @Franco_Piva @Bella_Carmelita_Carr

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I think it can depend greatly on the location and current market trends- as we saw the last couple years, for instance, the price of timber can increase drastically because of global or regional disasters like the pandemic. However, there are a lot of potential opportunities for reducing budgets with the use of Mass Timber-- it’s much lighter than concrete and steel frames, without reduced strength, so builders can easily end up using less raw material overall for a similar structural result. This becomes especially important with the foundation, which can be smaller and shallower than with a concrete structure, because wood is relatively lightweight. Similarly, you can potentially design for fewer load-bearing walls or columns on interior spaces because the layering of timber panels is so strong. In many cases, the modularity and possible pre-fabrication of elements can also reduce construction times, and therefore costs.

Conversely, I think the main issues with cost have more to do with mass production versus customizability- if more people were building with Mass Timber, mass production of specific elements could result in lowered costs overall? Also, I know there could be more innovation when it comes to integrating electrical/ mechanical systems into Mass Timber systems more seamlessly, that could also reduce costs. Lastly, I think building codes are still very conservative and sometimes contribute to increased Mass Timber costs, depending on the area. I wonder if policy could help incentivize the implementation of Mass Timber on a national scale, if more subsidies geared toward sustainability were developed?

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Some considerations:

  1. Mass timber as a material (wood fibre) is often more expensive than an equivalent concrete and steel (may not be the case currently with supply chain issues of steel)

  2. Mass timber is lighter as stated previously resulting in less foundation materials, lighter lateral systems, less cost of these components, lighter cranes, etc.

  3. Installation time of mass timber can be >20% faster than equivalent concrete because you don’t have to wait for formwork or curing times, requires less on site trades as the skilled work is completed in the mass timber factory

  4. Job sites are cleaner, more quiet, and less busy. Trucks arrive on site with materials, crane lifts materials off the truck into place, truck drives away, repeat. If storage is required then a storage location may be required. Continuous concrete deliveries are not required during the duration for mass pours during mass timber install scopes.

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Great contribution @Nic_Maloski!
So you are saying Mass Timber cost’s more money (may not be the case today), but needs less/smaller equipment, less labor, less time, and creates less of a mess. Is that right?

Given the supply chain issues, would you say steel prices have increased more than wood fiber (relatively)?

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Mass timber as a building/structural material often costs more than an equivalent concrete/steel building, but the savings associated with less construction time, less foundation/labour costs, earlier occupancy, etc. can make mass timber buildings more cost effective than the comparable concrete/steel buildings.

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How does this change depending on building type (office buildings vs. apartments vs. schools, etc)?

@Nic_Wilson @Aitor_Arteta @tim_hanson @David_Stallcop @Igor_Adriaensen @David_Bagdy @Andrey_Tikhomirov @Neill_Gibson @ARNIE_DIDIER @Dusan_Milutinovic @Oleg_Semenov @Steve_Marshall @KayCee_Hallstrom @Jerry_Truex @Josh_Trayner @Franco_Piva @Bella_Carmelita_Carr @Nic_Maloski

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All great points about the construction process and time savings resulting in lowered budgets! Another key consideration is might be the specific location of a building: 1) Which part of the country it’s being constructed in, i.e. close to sustainable forests or not, what the building codes are in the area, etc. 2) If it’s an urban construction site or more remote one- building costs could be greatly reduced with modular Mass Timber, for instance, if an urban site has a specific space constraints, or is an area of high traffic within the city. Fabricating elements off-site can be hugely cost-effective depending on different construction needs and requirements.

Similarly, I think this can be applied to different building types. If an old school or apartment building is being replaced with a new (Mass Timber) one on the same site, it would be much less disruptive to build over the course of a month or couple months using pre-fabricated elements, rather than needed to close down the original building and relocate the residents/ students for up to a year or more. Maybe someone else has more of an idea about how the program of a building changes the costs of raw materials and specific structural components in general?

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omg @Bella_Carmelita_Carr there is so much to unpack here!!

One element you are mentioning is proximity of the building to a Mass Timber manufacturing site. Since off-site fabrication is a cost-saver. However that needs to be balanced with the cost of transport.

Which brings me to the following question: what is the smallest fabrication plant for mass timber in terms of square feet? So square footage that would meet the minimal requirement of the product being produced and the equipment required? Any idea @Nic_Wilson @Aitor_Arteta @tim_hanson @David_Stallcop @Igor_Adriaensen @David_Bagdy @Andrey_Tikhomirov @Neill_Gibson @ARNIE_DIDIER @Dusan_Milutinovic @Oleg_Semenov @Steve_Marshall @KayCee_Hallstrom @Jerry_Truex @Josh_Trayner @Franco_Piva @Bella_Carmelita_Carr ?

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