Category Archives: New Buildings

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

 

Wonders all around us

WestlakeCnstrctn-2The great thing about commuting – and yes, so far, I’ve only found one – is that it gives you time to think, and that thinking can often take you down an interesting path – especially when, in my case, I see all kinds of construction going on in my daily travels: roads, homes, condos, stores, bridges, hotels, even full-fledged skyscrapers.

Just from my office window, in fact, I see no less than three new office buildings being constructed and another undergoing a major renovation. Move to a different window, and I see over a dozen construction cranes and at least three or four tall buildings going up in the downtown Seattle area.

These projects make me both think and wonder. I think about their complexity and the integration of myriad systems and materials, and I wonder how people make them happen, how they efficiently schedule and manage so many people and processes. For my money, the expertise on display especially on these big projects is something to be truly admired. I know that the knowledge and methodology and efficiency that goes into designing and constructing these buildings has been honed over generations, but, to me, it’s all still quite amazing. The art of construction (and architecture, and building design) just keeps advancing. And while many of us see it every day, I wonder – there I go again — how many of us pause with any regularity to think about what we’re looking at.

If you haven’t lately, take a few moments next time you’re stalled in traffic or maybe stopped at a traffic light anywhere near downtown Seattle. Locate the nearest major building under construction and consider the accumulation of real knowledge and expertise that you’re looking at. If you look closely, there’s plenty to see.

 Hey, move it along, buddy. The light is green!

Millennial madness arrives in Seattle

Alley111Image courtesy of Blanton Turner

 

Catering to millennials seems to be an emerging theme for many developers in the Seattle area.
Kilroy Realty’s 333 Dexter office project in Seattle was designed for millennials, Skanska USA Commercial Development’s Alley 111 apartment in Bellevue has millennials in mind, and even Daniels Real Estate’s The Mark office/hotel tower in Seattle has elements that will attract the younger crowd.
Want to find out how these developers are designing their projects for those 20- and 30-somethings? Click here to check out the DJC’s latest special section covering urban development.

See what local firms can do with concrete

CCtab2015

 

The DJC’s annual special section on concrete is now available. Its focus is on award-winning projects by members of the Washington Aggregates & Concrete Association.

There’s also a great article by Melanie Cochrun of GLY Construction on how her firm used 600 workers to make two record-setting concrete pours earlier this year in Bellevue.

Check it out!

 

Check out what’s happening in the local construction scene

VWDealershipUDistrict

 

The DJC has published its annual Construction & Equipment special section. It’s a mix of industry articles, profiles of local award-winning projects and a few interviews with the contractors who make it all happen.

Read all about it at www.djc.com/special/construct2015

 

See what’s trendy at the Seattle Home Show

SeattleHomeShow_AxiomDBHouse

Axiom Design Build, one of the exhibitors at the home show, raised this Queen Anne house onto a new foundation and added to the back.

 

The Seattle Home Show opens Saturday at CenturyLink Field Event Center.

Promoters of the 71st annual event put a list together of what is trending for the show. Here’s what they found:

  • More sophisticated laundry rooms, with formal space such as countertops to fold clothes.
  • Home styles moving in two directions: warm and rustic; sleek and modern.
  • White ceilings and muted walls.
  • Finishing extra space, such as over a garage or in a basement, for extended family or to rent out.
  • More homebuyers from foreign countries with extended families are creating more demand for bigger homes with multiple bathrooms.
  • Large walk-in showers are replacing bathtubs.
  • Older people are selling their homes to Gen Xers.
  • Baby boomers are downsizing from houses to condos, and are using equity to fix up their new digs.
  • Millennials are starting to enter the market and are looking for earth-friendly, smaller homes with more amenities.
  • Heated and covered outdoor living areas.
  • Outdoor kitchens, fireplaces and other luxury items.

Not trendy? The home show is holding an ugly couch contest, where the winner will get a $2,500 gift card from My Home Furniture & Decor.

The show runs until Feb. 22. Adults are $12, seniors $8 and juniors $3. Check it out at www.SeattleHomeShow.com.

DJC profiles the Apple Cup of construction

 

Just in time for the Apple Cup football game, the DJC has put together a special section profiling construction projects at the UW and WSU.

Included is a list of the top 10 projects at each school. Who gets bragging rights? If you go by dollar volume, the nod goes to the Huskies, with just over $900 million. That’s more than twice the value of WSU’s top 10.

UW also has the top project: the second phase $186.3 million expansion of the UW Medical Center. WSU’s top project is the $96 million Veterinary and Biomedical Research Building. Of course, WSU’s list of projects includes a $23 million Wine Science Center stocked with 3,500 bottles of wine.

For those wanting to watch football, the Apple Cup will be held Nov. 29 at Husky Stadium – another new project!