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21-Story Mass Timber Building Proposed in Milwaukee

The residential tower would be the highest mass-timber building in North America

A 21-story mass timber building proposed in Milwaukee, Wisconsin, has won preliminary approval from the city. If construction moves forward as planned, the Ascent tower would become the tallest mass timber building in North America. Image credit: Korb + Associates.

In Milwaukee, a city panel has given preliminary approval to plans for a 21-story apartment building whose upper floors would be built with mass timber components instead of steel.

The 238-foot-tall tower would become the tallest mass timber project in North America, according to an article published at Urban Milwaukee.

Construction of the “Ascent” tower would start later this year. The first four floors, housing a parking garage, would be built conventionally — with concrete. From there up, mass timber will replace steel and concrete structural components.

The tallest timber structure built to date is an 18-story student housing complex in Vancouver, Canada, but a number of taller projects are in the works.

Advocates like mass timber buildings because they have less embodied carbon than conventional high-rises made with concrete and steel. Using prefabricated components that have been manufactured off-site also speeds up construction, and the aesthetics of leaving some wood exposed is a plus for some designers.

The architect for the Milwaukee project is Jason Korb of Korb + Associates, who detailed the project for the City Plan Commission late last month. The panel unanimously voted to recommend the building for approval when it goes before a Common Council committee.

Mass timber construction is unusual in single-family houses. David Murakami Wood built a house from prefabricated timber panels in Ontario in 2016, a project he wrote about in a series of posts at GBA called Wolfe Island Passive. The cross-laminated timber (CLT) walls were more than 4 inches thick, which Wood insulated with a continuous layer of fiberboard.

Building a house with conventional framing materials would have been much easier. But using mass timber to build high rises is another story, and a number of projects have either been completed or proposed in the U.S. and abroad. In Japan, a wood products company called Sumitomo Forestry has proposed a 70-story timber skyscraper, according to the website Dezeen. The design is a hybrid that would use both wood and steel components.

Approval from the ICC

Tall mass timber buildings may become more common now that the International Code Commission has approved the use of materials such as CLT in buildings as tall as 270 feet, BuildingGreen reports.

The concern among building officials has been what happens to a mass timber building when it catches on fire.

Tests overseen by the ICC’s Ad Hoc Committee on Tall Wood Buildings included torching a full-scale, two-story mockup of an apartment building to see what would happen to the wood components. The chairman of the committee, Stephen DiGiovanni, told BuildingGreen, “No collapses, no structural failures, and the fire was contained within compartments.” Delamination of mass timber parts was “not an issue.”

Construction Dive said in a post last December that the ICC proposed 14 new provisions for tall-wood buildings, to be added to its 2021 code. The changes will allow three types of mass timber structures, including an 18-story maximum in which gypsum wallboard must be used on all mass-timber components. Buildings up to 12 stories would be allowed to expose limited areas of mass timber walls and ceilings. In buildings up to nine stories, exposed timber surfaces would have to be designed for two-hour fire resistance.

The Portland Cement Association has been a critic of tall wood construction. But the ICC’s ad hoc committee on tall wood buildings rebuffed a number of objections, including concerns that wood offer as much fire protection as steel and masonry buildings.


  1. PAUL KUENN | | #1

    So much for our Cream City Brick! Our fire departments here in WI have shown you just can't burn old timber, many derelicts have tried. If it does, beer will put it out. Milwaukee Shines is also very progressive with all the solar PV being installed. We're way more than just brewers these days.

    1. Expert Member
      MALCOLM TAYLOR | | #2


      This one across the straits from me is already up!

  2. tommay | | #3

    Sounds like another 9/11 in the works. Burn the top few floors for a total collapse, or maybe like CA, the steel structure will disintegrate while the wood stays intact, the new normal.....

    1. Expert Member
      MALCOLM TAYLOR | | #4

      A pretty cynical comment.

      1. tommay | | #5

        There is a whole world of info out there, besides this site, on this internet thing, check it out.

  3. JC72 | | #6

    Excited to see how this turns out.

  4. TameTheFlames | | #7

    Mass Timber needs fire protection during construction from arson attacks. I have a white paper report that makes Mass Timber Class A with accredited E84 extended 0 flame spread and 20 in smoke index with E119 results with less char. I’m talking to 3 Fire Marshalls that agree its needs protection during construction. Im the Inventor and patent holder of Mighty Fire Breaker Job Site Spray defending builders from arsons all around the USA. If anyone really cares about the Green Side of Mass Timber like I do you would consider defending the carbon storage left behind in the lumber. I have written a Carbon Tax Credit Bill that is now on the hill being reviewed by a Senior Legislative Official hoping to reward builders with a Carbon Tax Credit when the lumber is fire defended so the carbon is never released back into the ozone in a fire. This would promote more reforestation to sequester more CO2 why would you all want to cut safety corners when we have no history of an arson attack on a mass timer yet we we have lost 19 5 story stick projects this year to suspicious fires under investigation. The cost to fire defend mass timber could be absorbed by the risk premium reduction.

  5. TameTheFlames | | #8

    NYC FDNY and DOB is now looking Mass Timber and they have my White Paper Report now since they have turned down mass timber up until now. I’m trying to help this movement and many of the Insurance Underwriters want less risk and when we deliver less risk we have less cost to build so we can compete better against steel. Why is it that steel buildings have to fire treat but some thing mass timber needs no during construction fire protection?

  6. TameTheFlames | | #9

    I’m willing to help with a special discount for the first Mass Timber Builder willing to help this movement really get off the ground by adding Class A Fire Protection to get Fire Fighters behind this more because we make them safer. Lets face it guys smoke and fire kill more then structural failure. I know national builders that took mass timber off there pipe because its not competitive. I know the Insurance Premiums are high because of risk. What Structural Engineer will stand behind one of these building that has a fire during construction when it comes to replacing what was destroyed. Its not worth it and its not green and worth of a Carbon Tax Credit until we fire defend and defend that carbon stored to make giant carbon defended storage banks. If any mass timber producer is willing to do a live burn there raw mass timber verses my mass timber with fire defense live filmed in a fire training center I’m ready for the challenge. I was with the GC on the BC project in the Prototype offering them fore protection back then and they chose drywall. Drywall is great does nothing on the way up when sprinklers are not active. Tame The Flames is a 45 year wood veteran in support of mass timber and reforestation with fire protection otherwise we risk setting this great movement back with one arson attack.

    1. Expert Member
      MALCOLM TAYLOR | | #10

      Okay enough. We get it. You have a product you want to flog.

  7. TameTheFlames | | #11

    Malcolm what does flog mean? Are you saying do I have years of testing on mass timber to make it safer and better with less risk to help it get vertical in more jurisdictions? Yes

    1. Expert Member
      Michael Maines | | #12

      Flogging = selling. Advertising your product on this site is forbidden.

  8. TameTheFlames | | #13

    Michael you must be part of Wood Works. I’m not selling bro this is Applied Fire Science not just me its about adding more to raw wood then char value that you have no history in other than laboratory testing. I have real world testing outside the lab to prove my claims. Im a supporter of wood framed building fighting negative propaganda from the steel and concrete guys for years. Now that you know who I am tell us who you are so we can get real in this conversation bro.

    1. Expert Member
      Michael Maines | | #14

      No, I am not part of Wood Works, just a long-time member of this site, answering your question to Malcolm. Also, not your bro.

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