Category Archives: Materials

Impact of Water and Climate When Talking About CLT

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 guess it’s the Peter Pan syndrome…

Stark James / Phoenix AZ

There’s just something very cool about the developments we’ve seen in recent years in converting shipping containers to apartments. There’s an appeal there that seems to resonate, at least with me, on many levels. (The image here is from a recent project by StarkJames Architects in Phoenix AZ.)

Of course, there’s the sensible, “green,” helping-the-world aspect of taking an existing limited shelf-life item like a shipping container and re-using/recycling it into an actual home. That’s obviously a very good thing.

There’s the financial and economic-advantage aspect, too, of innovatively using these containers to create a space that’s very likely far more affordable than conventional construction methods might allow.  That’s nothing but good as well.

There’s also the outright and undeniable cool factor of these creations, with their own modern and minimalistic vibe that’s really unlike anything else out there.

Then of course there’s the simple, no-nonsense appeal of using these Lego-like “building block” shipping containers to create fresh and inspiring personal spaces that are all our own.

And there we have the essence of it all, at least for me.

These are simply the coolest fort any kid could ever want to build. They’re made out of boxes, fergodsake — I’m guessing that cats absolutely love them — and what kid didn’t spend some time in his or her early years letting imagination run wild in a big discarded cardboard box? Your own little space that could be a spaceship, an aircraft carrier, a car or even a home to call your own. And in my case, and maybe for many others, the box was just the first step. You know, kind of like a gateway drug, except in a good way.

Before long, I was building forts at every opportunity. I had forts made of lumber scraps and tarps, forts that used a fence as one of the walls, underground forts with tunnel entries that even had covered and camouflaged doors, forts carved out of dense ten-foot-high bamboo stands, forts with functional windows and hidden entries, tree forts in trees and forts built between adjacent trees. Lots and lots of forts. The forts of my childhood years, in fact, are like mileposts on a highway.

So I have to think that it’s a natural progression for any former fort enthusiast, such as myself, to look at these container-built homes with a special affinity, a special lifelong connection. Maybe these structures recall simpler days when all your worldly possessions — or at least a few of your most treasured ones — would fit in your own little space, right there next to you, with nary an extra square foot to spare.

And at least for a while, you could imagine needing nothing more.

  • Sean Lewis


Huge apartment fire blamed on maintenance and light-weight wood



(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.

One woman told CBS2’s Meg Baker that her dogs were both killed.

“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.

CMU Firewall Saves Multi-Family Structure from Disaster

photo 3A 50+ year old wood frame apartment complex in Airway Heights caught fire recently.

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.

L&I doing the home show circuit

The Department of Labor & Industries will have a booth at 18 home shows this winter/spring throughout the state to inform homeowners about hiring the right construction contractors.

L&I says home show attendees in search of a contractor should arrive with a plan that includes:

• Know what you want. Whether planning to update your bathroom or build a fence, write a list of the features you must have versus the features you’d like to have. Bring magazine pictures of desired features.
• Talk to a variety of vendors and contractors. Bring a list of questions about your project and ask contractors about their experience.
• Confirm prospective contractors are registered with the state at Registered contractors must have a business license and a current certificate of liability insurance and a bond on file with L&I, providing some recourse if the project goes bad. Just because contractors have a booth doesn’t mean they’re registered.

The first event, the Tacoma Home & Garden Show, is running until Sunday inside the Tacoma Dome. Admission is $12.


The Construction Industry is Invited to the 2011
Friday, August 12, 2011
2:00 p.m.-6:00 p.m.
6737 Corson Avenue, Seattle WA
Western Washington Masonry Trades Training Center

With thousands of years of proven performance, masonry construction has produced the world’s most enduring structures from the pyramids in Egypt to our local schools and homes in every neighborhood. Craftsmen have perfected this trowel trade by mastering building techniques passed down from generation to generation providing building owners with lasting projects of the highest quality in a timely manner. The time has come to put those highly honored skills to the test and prove who “The Best Bricklayer in the Puget Sound” is!


The SPEC MIX Bricklayer 500® Competition is a masonry competition that highlights the skills of true journeymen masons, QUALITY WORKMANSHIP where the winner will receive cash and prizes as well as a trip to the World of Masonry in Las Vegas, Nevada, to compete in the National Competition where the winners will take home more than $100,000 in cash and prizes.

Each of the competing teams will consist of one bricklayer and a mason tender. Teams must exhibit skill, speed and stamina to build a 26-foot double-wythe wall, laying as many brick as they can in 60 minutes. With a strict set of rules and guidelines, competitors will be judged on meeting the quality standards of the contest as well as the total number of bricks installed.

Project breakdown start to finish, Insulation vs. ventilation

I would like to launch into a series of topics for discussion starting with foundations and working through each phase of a project to completion, but first to launch this endeavour I would like to do something to honor the current weather conditions and how it affects us. This is a sample of the topics to come, please feel free to submit any topic suggestions that you would like discussed during this series.

Attic ventilation and insulation is something most people never have much cause to think about, for single family and multifamily structures already completed there are ways to check if your attic is functioning properly, for new construction the same checks apply. Why is this important? 1. Heating & cooling loss = $$ out of your pocket 2. Damage can occur from ice damming and condensation 3.dry rot from insufficient venting. So what causes these issues? the concept of the conventional roof system is to insulate the ceiling (currently R-38 for attics is code) and vent the space above. Keeping the temperature of the attic close to the same temperature as the outside is very important.If the outside air is colder than the attic then cold air enters the attic through the improperly vented roof system it hits the warmer air and freezes any moisture in the warmer air. The other thing that happens is any metal (roofing nails, cast iron vent pipes etc.) that penetrate the roof into the attic do what is called thermal bridging, you may have seen something like this on aluminum windows where condensation freezes on the inside of the frames then melts creating a mess, roofing nails through the roof will rust and eventually allow water to leak in.

What’s the solution? first check to see what the depth of your insulation is, bat and blown in insulation is typically R-3.75 per inch so an 8″bat or blown in depth = R-30 which is pretty good! Next check to see all ventilation is in place and clear (sometimes the insulation blocks off the eve vents) next make sure there is an airflow pathway such as eves to gable end or ridge vents and that they are sized properly for the space (venting charts are available), this will keep our attics cold and living space warm in the winter with proper insulation. During the summer it works in reverse, hot air is ventilated out of the attic limiting the heat gain into our homes through our roofs while eliminating dry dry rot issues. In extreme cases the damage caused requires full roof replacement, climates definately play into the “extremes” however the solutions are the same, check with a local design professional or building inspector to see what is recommended for you region.

Matt Stodola

Largest plumbing recall in U.S. history coming?

Consumer advocacy group America’s Watchdog says it is ramping up for what could be the largest defective plumbing recall in U.S. history. The product in question is a brass fitting inserted into cross-linked polyethylene tubing.

“We think there are literally 100,000s of U.S. homes that have a specific defective plumbing product called Uponor, or RTI P Pex, or MB Pex fittings, and according to court papers these will fail,” the group said in a press release. “We’d call this your basic homeowner nightmare — because we think the fittings will continue to fail, and fail, and fail — unless they are all replaced.

“Plumbers, who have recently repaired an Uponor, or its wholly-owned subsidiary Radiant Technology’s P Pex, or MB Pex brass plumbing fitting, should contact their clients, and ask them to contact us immediately.”

America’s Watchdog says the fittings are advertised and warranted for as long as 25 years, but some have failed months after installation. Failed fittings can cause water damage to walls, floors and personal property. The fittings allegedly fail when they are exposed to water because of a chemical reaction known as dezincification, which results in reduced water flow and leaks.

The fittings are identified by a “P Pex” or “MB Pex” stamped on their side.

The investigation by America’s Watchdog involves homes and buildings constructed nationwide from 2004 to 2007. For more information, contact the group’s Construction Defect Center.

Bad Recipe: Input Costs Up, Finished Prices Flat

“If you’re in the industry now, if you’ve survived to this point, you have great career prospects.  The construction industry will get back to average levels, and you’ll be in a great position.”

National AGC Economist Ken Simonson gave that positive assessment to a group of early and mid-career construction professionals who make up AGC’s Future Leadership Forum.  That positive note was perhaps the only bright spot in the gloomy assessment that Ken provided about the current and near future of the construction industry.

One of the more alarming trends Ken cited was this:  Over the last year the cost of the inputs of construction is up 4.5 percent, but the price of finished products/buildings is flat, even slightly down for segments like new office buildings and warehouses.  “This is a recipe for driving contractors out of business,” Ken noted.

Some of his bottom line predictions:

2010 will conclude with non-residential construction spending down 15-20 percent.  More stimulus money is being put in place, and maybe small gains in retail, higher ed, and hospitals, but that’s about it.

2011 is the year the industry bottoms out, Ken said.  But, having reached the bottom, it’ll then be up (oh so slowly).  Next year non-residential construction spending should range from flat to 5 percent.  There will be less stimulus spending and state and local government spending will be weak, but some increases in retail, hotel, higher ed and hospitals.

This relative optimism for next year stems from several months’ worth of small but consistent increases in GDP and recent steady growth in private sector employment.

For now we should look for “pinpricks” of growth on the map – small geographic areas with their idiosyncratic causes of growth, like being net winners in the military’s base realignment efforts or being home to alternative energy efforts.

AGC National Economist Ken Simonson, center, with AGC Future Leaders (photo by Sarah Teague)