Cross-Laminated Timber (CLT) is the trendy new building material that has received a lot of attention in the northwest this year. It is by definition a series of thick boards (usually 2×4 or 2×6) glued together in an alternating pattern and Cross-to form a solid wall, post or beam. (A similar concept is glue laminated (glue lam) timber that has been used for beam construction for many years.)
To understand how water affects wood construction, one must understand its function in a tree. Wood is designed to provide structural support for the tree, move water from roots to leaves and store the chemical results of photosynthesis (primarily sugars in the form of cellulose). These properties of wood create some challenges for its longevity when exposed to moisture. Thus, while wood can be structurally strong, it naturally absorbs and retains water.
Depending on climatic conditions, it can take some time for CLT panels to fully dry after getting wet. So, moisture control is of utmost importance when building from wood, such as cross-laminated timber.
The first source of moisture concern is during manufacturing. While manufacturers try to have all of their boards have the same moisture content, wood is an organic material and each board reacts to moisture differently. Some take water in more quickly and some take longer to dry. The result is that boards swell and shrink at differing rates which can affect the performance of a CLT panel.
Think of the hardwood floors in older buildings where the floor buckles in places. That is what happens when one board expands against another. As the wood dries again, it shrinks. This expansion and contraction process can damage the wood causing new cracks and gaps. On a floor, one can just refinish it. But, CLT is an integrated structural component and any deformity can weaken its life-safety purposes.
Another source of moisture is environmental moisture during construction. Studies indicate that construction moisture wetting is a serious problem in rainy climates like the Pacific Northwest. It can take several years for the wood to fully dry after construction. With rainfall likely in any month of the year, it is vital that proper precautions be taken to prevent the wood from getting and staying wet.
It is not just rainfall that is a concern. Other sources of moisture must also be accounted for, such as sprinklers, groundwater, pressure washing of siding, sidewalks, driveways, etc. decorative ponds, swimming pools, or other sources of moisture.
Wet CLT panels built with wrappings that do not allow vapor to pass through (both interior and exterior) are much more likely to develop bio-deterioration. There are vapor permeable wrapping on the market that can mitigate this concern to some extent.
Exterior cladding also plays a significant role in preventing moisture penetration. Not long ago, there were significant problems with wood frame buildings experience the negative effects of prolonged moisture, especially condominiums. The resulting lawsuits bankrupted many developers and contractors. With CLT, the stakes are even higher. With wood frame, the walls can be exposed, dried and cleaned. Since CLT is a structural system, that process is much more difficult and expensive.
In comparison, concrete, masonry and block all dry very quickly when wetted. Any remaining moisture can be removed easily (similar to using your shop-vac and a floor-squeegee in your garage after a big rain). Thus, construction moisture is of much less concern. And, there is no concern with rot with concrete, masonry and block construction.
One solution is to cover the CLT panels during construction until they are clad with the exterior components (be it siding, brick or stone). This is complicated, expensive and time consuming. Thus, covering panels during construction can undermine the presumed time and cost savings of CLT construction.
Another possible solution is to install water and air barrier membranes when the panels are manufactured. To date, no manufacturer is doing this, presumably because it would be cost prohibitive.
Certainly, more research needs to be done before the public can be assured of the safety and environmental impacts of cross-laminated timber panels used in construction. Also, new additional building code standards and construction practices would need to be developed to mitigate the health, life-safety and structural concerns posed by our wet climate on CLT buildings. Current building codes allow wood structures to be built up to five stories. The talk is some would like to go up to as many as 20 stories with CLT.
The risk of fire in a wood building has historically been the primary concern with high-rise wood construction, but, water and climatic conditions can have an equally and perhaps more insidious impact on the construction.
CLT may have the potential to be a sustainable building product that lowers the carbon impact of building. But so do proven products like concrete, steel and masonry.
While fire is an immediate and known risk, water’s impact is subtler, but no less threatening. This is particularly true in the Northwest from the Pacific Coast to the Cascades.
I was out recently on a construction site, doing a little photographic work, when I had another one of those blast-from-the-past moments in which we all, I assume, occasionally find ourselves suddenly immersed. In this case, as best as I could determine, it was instantly sparked by the smell of dust and concrete, with notes (I borrowed that term from a wine label) of something metallic. That had to be it — the unique blend of those elements, in just the right blend, that we apparently only take in on an active construction site.
As it has many times, that scent alone instantly took me back to when I was a little guy, fifty years ago (good lord, did I just say that?), occasionally visiting jobsites with my dad, who ran the Richland, Washington branch of Lord Electric (does anyone remember them?). He was The Boss, of course, which was quite cool, but I also really enjoyed those visits because I got to wear the hardhat and see stuff I sure didn’t see elsewhere: big pieces of construction equipment; the bone structure of halfway-built buildings; lots of different tools, fixtures and materials, and lots of people bustling around. Lots of pickup trucks, conduit, extension cords and cool lunch boxes too, as I recall.
This all made me think about what has, and what has not, changed on a construction site in half a century. For the most part, they still look very similar, but of course the materials, tools, techniques and practices – and certainly the pickup trucks and lunch boxes – have evolved quite a bit. In some ways, the people have changed, too, but in others, they have not; people have always, and will always, simply love to build things. That has to bring about a kind of satisfaction and pride that you don’t often find elsewhere.
And all those thoughts went through my head in a matter of moments.
Somewhere out there today, I’m sure there’s a superintendent or foreman or project manager on a jobsite with a son or daughter tagging along, taking in the sights and smells of all that’s going on around them. And likely creating little snippets of memories that will last — well, as we know now — at least half a century.
– Sean Lewis
It was great to see, earlier this year, state legislators respond appropriately to efforts by many in the construction industry to stop a proposed bill that had good intentions, I’m sure, but would be neither practical or effective.
House Bill 1754 would have mandated the listing of many building-envelope subcontractors, beyond the many already often required, at the time the lowest-responsive-bid general contractor was identified on a public-project bid.
Hardly an issue critical to world peace, but this one struck a personal chord with me.
As a past bid-runner for one of the region’s larger GCs, I’m pretty familiar with how bid days go on any mid- to large-scale project. Bidrooms are hectic and pressurized; there are myriad last-minute calls to make, bids coming in left and right; coffee consumed by the gallon. The amount of critical data that has to be accurately processed by the bidding team can be staggering. The clock literally does tick down to the last second as the guy or gal on the other end of the phone – me, for sixteen years – waits for the final numbers before completing the bid forms, sealing the envelope and slapping it on the counter — while, of course, trying to look as calm and collected as possible (sometimes I’d fake a casual yawn, even, for maximum effect, but really, I’m almost out of breath just describing it). It gets a little hairy.
Typically, submitted bids are then opened immediately by the owner. GC’s bid packages often include a base price, a number of itemized alternates and a number of lowest-subcontractors’ bids on major scopes of work. While the building-envelope scope is of course a critical component of any project, adding yet another sizable group of firms and bids to that list of immediately required data, to me, is just too much and unnecessarily compromises the team’s ability to deliver the truly critical numbers.
Doug Orth, of the State Building Code Council, put it well when testifying last May before the Senate Ways and Means Committee: “The way the bill is written, I would interpret the envelope as everything outside of the paint. That is everything from structural systems, window systems, framing systems, insulation systems, brick, masonry, glazing, roofing — everything. It’s not possible to list them all within days or a week.” Orth was joined by AGC’s Duke Schaub and Tymon Berger of Ashbaugh Beal.
The bill had already passed the House, but ultimately, it died in the Senate — which was good news for GCs and estimators, and especially for my fellow members of The Brother/Sisterhood of Construction Bid-Runners (it’s a secret society; that’s all I’m permitted to tell you).
Each fall, the Associated General Contractors of Washington hosts an annual “Past Presidents & Old-Timers’ Dinner” night (they all seem take that name in good humor) to honor its many past presidents and honorary members. I was able to attend my first of these events last fall.
Talk about sitting in a room full of history.
I’ve been in the construction business for over twenty years and was surrounded by names – some of whom I knew and had met before, but many I’d only heard and read about. Names like Wick, Young, Paup, Deeny, Clark, Crutcher and many more. Not to mention Frodesen – that would be Mr. John Frodesen – who was in attendance that night and who’d been AGC president back in 1965. Sheeesh.
As you can imagine, there’s no shortage of amazing stories that are rehashed at an event like this – stories of how buildings and roads got built in the face of adversity; how technical impossibilities were overcome; how schedules were met (or not), how near disaster was averted (or not) and sometimes even how disaster was simply survived. Plenty of successes and yes, some failures along the way too. But so much survival and perseverance, and moving on, one step and one day at a time, like building a massive building, brick by brick. It was quite a collection of in-the-trenches experience, business acumen, good instincts, technical smarts, of course, and — maybe most of all – “people skills.” And you can only guess at the vast amount of knowledge this group has passed on to others over the years that goes into many of the very buildings we see going up around us today.
As we enter a new football season (thank God), I’m reminded of one particularly timely anecdote that came to light that night.
Back in 1976, local businessman and developer Herman Sarkowsky had his office in the AGC Building on South Lake Union. He also happened to be part owner of the Seattle Seahawks — and they needed a location from which to conduct their first-ever NFL draft. According to co-owner John Nordstrom, they ended up packing Sarkowsky’s small office full of people – GM John Thompson, along with Nordstrom family members John, Lloyd, Jim, Bruce and Elmer, plus a few more. Thompson’s son Rick was at the draft HQ table in New York, connected to Seattle by a single phone line, keeping the local boys up-to-date as the draft progressed. “There was no ESPN or internet then, of course — it was a little different in those days,” chuckled Nordstrom. Head coach Jack Patera, as Nordstrom recalled, was not present.
Their inaugural draft including names that some of you “old timers” might recall, like Steve Niehaus, Sherman Smith, Don Dufek and UW quarterback Chris Rowland – as well as some guy named Steve Raible who ended up catching his fair share of passes over his six seasons with the Seahawks. I hear he went into broadcasting…
Anyway, there you go. Just another little bit of construction-industry history that’s all around us. Go, ‘Hawks!
CEO Clyde Holland isn’t an ASU grad, as far I as know. So, what’s up with the Sun Devil flag? Did you lose a bet Clyde?
Maybe someone at Morrow, the crane operator, snuck it up there.
Don’t they know that this is purple and gold territory? Arizona isn’t even a Pacific coast state.
The reader described the flag as “utterly appalling.”
I had to talk him out of ascending the crane with his GoPro strapped on to remove the offending matter — didn’t want him to get hurt.
(This is the second fire at this complex since 2000 – while the project was under construction.)
EDGEWATER, N.J. (CBSNewYork) — Maintenance workers fixing a leak and using a torch is what started the massive fire at an Edgewater, N.J., apartment complex fire, officials said Thursday night.
As 1010 WINS’ Carol D’Auria reported, Edgewater police Chief William Skidmore said at a news conference the workers were using a blow-torch to make repairs to a leak at the Avalon at Edgewater complex, when a plumber accidentally ignited the fire in a wall.
Skidmore said the workers tried to put it out themselves and delayed calling for help for about 15 minutes. It is unclear how many workers were involved or where exactly the work was being done.
“They tried to suppress it themselves, and then they called their supervisor, which gave the fire a head start,” Skidmore said.
Fire Chief Thomas Jacobson said the delay in calling 911 put his crews at a disadvantage, WCBS 880’s Peter Haskell reported.
“It takes four minutes for a room to be fully engulfed and flash over so 15 minutes can make a big difference,” Jacobson said.
Officials also said Thursday a lightweight wood construction contributed to the fire, leaving hundreds of residents permanently displaced.
Edgewater Mayor Michael McPartland said a local state of emergency remains in effect due to the fire at The Avalon at Edgewater, which broke out around 4:30 p.m. Wednesday and raged for hours.
“It was a long and challenging night and I think every one of our first responders really stepped up to the challenge,” McPartland said.
McPartland said it was because of the good work of all the first responders that no lives were lost.
“I mean, I saw four brave men go into that fire and pull a woman out while the façade was coming down virtually on top of them,” he said.
The fire was brought under control by Thursday morning, but crews were still putting out hot spots and heavy smoke could be seen billowing from the structure even in the evening.
Jacobson said the fire appears to have started on the first floor and quickly spread through the floors and walls because of the building’s lightweight wood construction.
“If it was made out of concrete and cinder block, we wouldn’t have this problem,” he said, adding the building complied with construction codes.
Jacobson said the sprinklers were working and went off, but they were no match for these flames.
“It doesn’t get every area,” he said. “It gets the common areas where you can egress and get out. It gets your apartment. All the little voids inside every nook and cranny in the walls? No.”
Jacobson said crews simultaneously battled the fire while doing door-to-door searches and pulling people from the balconies.
“We had a crew trapped on the balcony with a victim; we had to rescue them with ground ladders from the back of the building. That was my concern first, not the building,” he said.
Firefighters from across New Jersey and from the FDNY helped battle the blaze. It was raised to more than five alarms Wednesday night and grew so large that the flames were visible from Midtown Manhattan.
As CBS2’s Sonia Rincon reported, the Bergen County Arson Squad investigated where and how the fire started, even though it later turned out to be accidental.
“A fire of this magnitude is an automatic response for the arson squad,” Skidmore said.
Schools were closed Thursday and will remain closed Friday. McPartland said access to some roads around the building would be restricted.
In all, 240 units were destroyed, permanently displacing about 500 residents, McPartland said. An additional 520 residents from other Avalon buildings have also been displaced, McPartland said.
“Don’t know where to even start,” resident Seoung Ju Won told CBS2’s Janelle Burrell.
“It was like a volcano eruption, really,” said resident Angela Nyagu. “That’s what I watched on TV before, how volcanoes erupt. Now I witnessed that myself.”
Among the residents of the complex was Yankees announcer John Sterling, who talked to CBS2 about his experience.
“I walked to the building and smelled smoke, and I went out to my floor where my apartment is, and the smoke was so bad I couldn’t see, and I thought, ‘Hey, we’d better get out of here,’” Sterling said.
And many residents, including Limor Yoskowitz-Frinomas, were still waiting to hear whether their homes were destroyed.
“We’re hoping for the best,” she said. “My kids are OK, so I’m OK, and we’ll take it from there.”
There were no reports of any missing persons, but McPartland said two civilians and two firefighters suffered minor injuries. He said some pets were rescued from the blaze, but some did die in the fire.
“I saw gulfing flames coming out of the building, and unfortunately, I have two dogs that perished in the fire – Hailey and Griffin,” the woman said.
This isn’t the first time the very same apartment complex has been engulfed in flames.
In August of 2000, the complex was under construction when a fast-moving fire tore through it. The flames also destroyed a dozen surrounding homes, displacing up to 70 people.
The 2000 fire was ruled accidental by the Bergen County Prosecutor’s Office. No deaths or serious injuries were reported.
The structure is a dry wood frame, with a CMU fire wall separating the building wings. This building’s CMU fire wall prevented the adjoining wing from catching fire. The front side of this structure received more damaged than the back which is shown in the photos.
This demonstrates the effectiveness of the CMU firewall component in multi-family and commercial structures. The masonry industry works hard to continually reaffirm the use of CMU firewalls in buildings in condensed, urban areas to protect the community from major catastrophic fires as well as other energy, lifecycle and environmental factors.
The Masonry Institute of Washington is available to provide additional information on all masonry systems for both constructability and aesthetics.
PCL’s Seattle buildings and civil groups donated $5,000 to Northwest Harvest Food Bank and another $5,000 to Food Lifeline to support those in need. This is the sixth consecutive year the Seattle office has donated to the two food banks for a total of $60,000.
“Thanks to PCL for joining us in the fight against hunger,” said Linda Nageotte, president and CEO of Food Lifeline, in a release. “We see the need for food continue to increase especially among children and seniors, our most vulnerable populations.”
According to Food Lifeline, one in six Washington households struggled with food insecurity at some point during the year, meaning food was uncertain or unable to meet the daily needs of household members.
The checks were presented to the food banks on Nov. 20.
In addition to the Seattle office, 13 other PCL offices across the nation are donating $130,000 to local food banks.
Over the last six years, the company has donated $868,000 nationally. That’s about 7.8 million meals.
Way to go PCL!
In the fall of 2012, AGC’s Seattle District began a partnership with the Center for Wooden Boats (CWB) to improve and repair CWB facilities. The most difficult project to come out of the relationship was the installation of a hoist system to mechanically raise historic small craft out of the water and into the floating boatshop.
This complex project was designed and engineered under the supervision of Dan Chandler at OAC Services and his team of professionals. OAC redesigned the existing boatshop by changing the roof line at the north end of the shop and strengthening the rafters to accommodate the 30-foot steel I-beam that cantilevers out over the water.
Dan then recruited other northwest companies to build the project. BNBuilders provided a team of carpenters for two weeks to complete the retrofit of the shop and installation of the beam. Additionally, they footed the bill for the construction materials provided at cost by Gray Lumber. BNB also recruited Precision Electric to rewire the area affected by the retrofit. Yakima Steel fabricated and supplied the custom beam for the shop, while Scott Galvanizing of Ballard finished the raw steel. Ballard Hardware donated the trolley for the I-beam, and Al Wirta of Wirta Architectural in Sultan fabricated the overhead winch and pick-frame system capable of pulling a one-ton keelboat out of the water.
In photo, CWB recently hoisted it first historic Blanchard knock-about from the water into the boat shed for repairs — a task that, for thirty years, had been accomplished with sheer manpower using a cranky old float plane drydock.