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Archive for March, 2011


This wall section drawing shows the increasing complexity of building envelopes as we ask them to do more and more for less and less. Unfortunately, the more complex the system, usually the greater the potential for errors.

Let’s face it, sometimes we would like to ask if anyone else has ever dealt with the particular situation that’s staring us in the face right now.

You could ask your co-worker in the next office. You can also ask a nationwide — perhaps even global — community of building enclosures professionals. You might not get an answer. You might not get the answer you were looking for. But it doesn’t hurt to ask.

And who knows, You might get the exact clue you needed.

An e-mail group of hundreds, or thousands of fellow professionals may not be a replacement for a qualified building envelope consultant, but it may be a place to start. It may be a place to FIND a qualified building envelope consultant. It may be a good place to be if you ARE a qualified building envelope consultant.

Maybe you’re writing something and you need a stat that you just can’t find anywhere.

Or you might have written a brilliant blog with something in it that you just know others could find really useful. Or found a really funny site that you’d like to share.

Being a member of the group is a way to build relationships, to help and get help when you need it. And although this group isn’t about marketing, advertising or self-promotion, is there a better way to promote yourself than by helping someone else?

You don’t have to check in and out. It’s just e-mail. If the subject line doesn’t appeal to you, delete it. It’s just a handy desktop resource with unlimited experience and brainpower — including, hopefully, yours.

It’s easy to join the Building Enclosures Group. It’s just as easy to leave if you decide you don’t like it. Here’s the link: http://groups.yahoo.com/group/BuildingEnclosuresGroup

gary

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This full-scale mock-up is ready for window installation and testing according to ASTM E-2112 standards.

In this post, the president of our company, David W. Boyer, an architect by training, exposes a bald and uncomfortable truth about the way we build — one that in my opinion there is simply no arguing with.

It’s a truth that must be faced before we can ever achieve true sustainability in construction. Why we must rethink the way we build
by David W. Boyer

Construction industry professionals – in an effort to take the guesswork out of how our buildings perform ‐collaborate in hopes of coming up with “best practices” that can be embraced by the entire construction industry.

One such effort is ASTM E‐2112, passed in 2007 as a “Standard Practice for Installation of Exterior Windows, Doors and Skylights.”

One of the articles announcing the publication of E‐2112 described it as containing “Instructions for complete integration of external wall components.”

The committee members who worked on E-2112 shared a common, praiseworthy goal – to create a product that promotes:

 Energy savings
 Reduced water leakage
 Enhanced durability of our building inventory
 Reduced maintenance
 Improved occupant comfort
 Enhanced value for our structures

E-2112 outlines and illustrates step-by-step installation procedures for exterior windows, doors and skylights. The following photo-sequence shows a mock-up constructed according to E-2112’s 21 steps, and then being tested in a Design Verification Test Chamber.

It starts with installation of a waterproof membrane into and below the window opening.

2. Install sheet metal tray.

3. Install sheet membrane into window opening.

4. Install shims.

5. Install window.

6. Install sheet metal head flashing.

7. Install Peel-n-Stick above from substrate to head flashing.

8. Begin building installation paper with drip edge flashing.

9. Install building paper, first layer, first row.

10. Install building paper first layer, second row.

11. Install building paper first layer, third row.

12. Install building paper first layer, fourth row.

13. Building paper installation first layer fifth row.

14. Install Building paper second layer, first row (stagger laps).

15. Install building paper second layer second row (stagger laps).

16. Install building paper second layer, third row (stagger laps).

17. Install building paper second layer, fourth row (stagger laps).

18. Install building paper second layer, fifth row (stagger laps).

19. Install building paper second layer, sixth row (stagger laps).

20. Lift second layer, fifth row at window to prepare for peel-n-stick.

21. Install peel-n-stick as shown. DONE! Next window.

The Design Verification Test Chamber is fitted with monitoring sensors to show at what point installed window and wall assembly mock-ups leak under various simulated weather conditions.

Water that contains a fluorescent dye is run through the calibrated spray racks and then viewed under a black light to help us locate any leaks that may occur. The assembly is being tested with 1.44 inches of water column at a pressure of 7.5 pounds per square foot, per AAMA 502.

Water becomes evident around the base of the window, about a minute into the test.

Two minutes into the test.

Severe leakage at 5 minutes in. Bettter to find out in a test on a mock-up than to let an unhappy building owner bring it to your attention after you've moved on to the next project.

There are two problems with having this many steps for window installation. First, each step creates multiple interfaces of material in the assembly. These interfaces of different layers and/or dissimilar materials are where air and water can leak through.

How many interfaces are there in this 21-step assembly? We counted — there are 74 places where air and water can leak through. And that’s if everything is installed perfectly, and in the precise order specified by E-2112.

Multiply that by, say, 300 windows, in a big building, and you’ve got 22,200 opportunities for air and water to leak through, carrying energy dollars away, stressing the HVAC system, creating conditions for mold, just to name a few of the problems leaky building envelopes offer.

Now I believe the American construction workforce is the best on the planet. But human nature being what it is, it’s only natural for even the most dedicated installer to daydream about the big ball game sometimes, and miss a step or two. How much more likely is that to happen in a process that’s both complicated and repetitive?

No wonder a five-year (1994-98) Environmental Protection Agency indoor air quality study of 100 randomly selected U.S. office buildings found 45 percent had ongoing water leaks.

But that’s what E-2112 was designed to remedy. Let’s imagine a perfect world for a moment, where workers never get distracted and details are always constructed precisely according to specification. That’s the world our mock-up comes from.

So now, of course, we test the mock-up, just to make sure it does what it’s supposed to do, before we actually incorporate the design and procedure into the building.

Because if we put an assembly into a multi-million dollar building without having tested it to the conditions it’s likely to face, then we’re just going on faith that it will stand up to those conditions.

And because that’s how so many otherwise prudent and responsible architects and contractors operate, there is a multi- billion dollar construction litigation industry that feeds on them and their buildings in which window and wall assemblies fail to resist the ravages of air and water infiltration.

Though it costs time and money to test and refine construction mock-ups, that cost is only a tiny fraction of a fraction of what it costs to fix after the building is up.

So, test how?

E-2112 does not call out a specific testing requirement.

That’s left to people like AAMA (the American Architectural Manufacturing Association – the window and door industry association) to spell out in their own test method 502.

AAMA 502 calls for testing at 1.44 inches of water column, which is equal to just less than a 55 mile per hour wind or 7.5 pounds per square foot.

So we install the mock-up in a Design Verification Test Chamber. The chamber, equipped with monitoring sensors, can simulate weather conditions from moderate to a Category 5 hurricane.

The chamber is first pressurized to 1.44 inches of water column or about a 55 mile per hour wind, per AAMA 502.

Within one minute of starting the rainfall, water becomes evident around the base of the window.

After 5 minutes leakage is severe. This was an unwelcome surprise to the people who commissioned this study. They were confident this method – one that they had already used on countless windows in the recent past, would stand up to this kind of pressure.

The testing highlighted just how difficult a “proper” installation is to carry out.

Even after taking pains to ensure the proper sequencing, lapping and overlapping, the system failed.

It allowed water leakage under what are fairly typical weather conditions all across the country.

Even more frustrating was trying to determine just where the leak began.

Most people involved in waterproofing realize that leaks typically originate at interfaces between different layers or dissimilar materials. But when you go back to de-construct this 21 step process, you’re left facing substantially more than 21 interfaces — 74, in fact, by our count.

So where does the failure, first noticed at the interior base of the installed window truly originate?

And how, once the window is in place, do you go about investigating and repairing that?

These questions point up some uncomfortable truths.

1. Many construction products and procedures — even some of our best, like ASTM E-2112 — are not designed for “real world” conditions. Twenty-one steps to install a window that, even when done perfectly, still fails in minutes under typical weather conditions is not real-world. And that’s just in a lab. We all know the real world can be a lot more brutal.

2. Many, if not most buildings, go up without their designers, builders or owners having a clue as to how well the building will perform when weather hits. Sometimes they’re lucky. Sometimes they’re not. Luck is no basis for sustainable design and construction.

3. The remedy is a simple formula:

Design
Test
Refine
Build

I’m not saying it’s easy. But those who follow it will surely have an easier time than those who guess and then get caught.

When our materials and methods take real world conditions into account, we will have taken a giant step toward sustainability.

When we know for a fact, from testing, that our buildings can withstand their environments, we will have arrived.
# # #

(That’s the end of David’s article. The installation photos keep going, and the test photos follow them – gary)

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At the risk of sounding like I’m sucking up, I have to say the president of our company, David W. Boyer, an architect by education, recently came up with what I think is a really good definition/explanation of sustainable construction.

There’s been a lot of debate over just what constitutes sustainability. Correct me if I’m wrong — that’s what the comment block on this blog is for — but I don’t believe anyone has yet delivered a clear, concise explanation of sustainability as regards design and construction.

There’s been PLENTY written about it.

For instance, the folks at Building Design & Construction authored a 48-page white paper on the subject in 2003. I’d be lying if I said I did more than scan it.

I DO read Building Design & Construction Magazine – the print version – each month. Highly recommended. But as far as being able to explain sustainable design and construction to my Mom in about a minute or two, I think David’s explanation does a great job.

David W. Boyer, President, PROSOCO


Why is a quick, clear explanation important? If we want “sustainable” to reside in the general consciousness of the market the way, say, “economical” does now, we better have that simple, common-sense explanation of what it is.

Here’s what David wrote on the subject:

If you boil the fat out of the sea of “green” marketing messages and “sustainability“ mission statements, what you have left is constructing buildings to be:

• Energy Efficient
• Durable
• Built with environmentally responsible materials

And for the most part I think the need to be environmentally responsible is a value all of us now share and try to embody in our designs. How else could you explain the rapid growth in popularity of:

• All things bamboo,
• natural fibers
• Recycled metal or glass or plastic or paper countertops
• Polished concrete floors

The drive for energy efficiency is behind the fast – almost irresponsible ‐ rate of change in the way we light, heat, and cool our buildings. But I submit that, while we are building more energy-efficient buildings, using more environmentally responsible building materials and practices, far too little attention is being paid to the durability of our buildings.

Because it doesn’t matter how energy-efficient your building is today.

You may have bamboo out the wazoo.

If your building does not survive its intended service life —
IT IS NOT SUSTAINABLE.

The 10-second seminar?

Sustainable buildings are:

• Energy Efficient
• Durable
• Built with environmentally responsible materials

Eight words. Good ones, too, in my opinion.

# # #

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A window assembly awaits its trial in a design verification testing apparatus.

I’m working on a technical paper about design verification testing. That’s the radical new concept of testing wall and window assembly mock-ups to failure for air and water penetration so that you can see exactly what their limits are.

Currently, when window and wall-assembly testing is done at all, it’s done to some arbitrary standard to which everyone hopes the mock-up passes. But then you don’t know where failure lurks.

That’s something that anyone who constructs or owns a building needs to know.

As part of my research I spoke with Tom Schneider. the Director of Product Development for Building Envelope Innovations, LLC. During his three decades in the paint, coatings and sealant industry, Tom has developed architectural and high-tech ceramic coatings; and structural waterproofing and air management applications for the construction industry. A product-testing expert, Tom likes to say “if we are not testing, we are guessing. Guessing is very expensive.”

Here’s the gist of what he told me.

Buildings often fail due to water and air intrusion. Weather happens.

Those failures often engender enormous litigation and repair costs.

Energy is wasted when water and air infiltrate wall and window assemblies. The North American Insulation Manufacturers Association (NAIMA) claims that up to 35 percent of heat loss in homes can be attributed to air infiltration, in their white paper The Facts About Insulation and Air Infiltration.

When the water vapor carried in that warm air condenses on cold surfaces within the wall assembly, it can wet out insulation and other components. Wet insulation has little thermal resistance.

Wet walls can contribute to Sick Building Syndrome.

Toxic mold Stachybotrus Chartarum grows within a wall assembly.

Sick building syndrome costs hundreds of millions of dollars annually, including the costs of increased respiratory illness and allergy rates from mold and mildew growing in wet walls.

Testing mock-up assemblies to find and fix leaks before construction — the proverbial “ounce of prevention” — is cheaper than repairing walls and windows when they do leak after the building is up. Yet testing is too often “not in the budget.”

If we are not testing, we are guessing. How willing are you to stake the well-being of a 20-story inhabited highrise on a guess? Incredibly, many construction professionals are willing to do just that.

If you don’t test your design with a mock-up wall assembly to the conditions the building is expected to face — a mock-up built with the same materials and procedures, by the same people who will do the building — Mother Nature will perform her own test.

Somebody got an "F" on Mother Nature's test for water infiltration into the rough opening.

And if she finds the flaw in the assembly — a flaw you could’ve found and fixed with a test — you could be liable for millions in repair costs. That’s the proverbial “pound of cure.”

Unfortunately, when there IS on-site mock-up testing, it’s typically inadequate.

That’s because the parties involved have a vested interest in the mock-up passing test. The contractor and owner both want the mock-up to pass, because if it doesn’t, that means delay and expense.

Sometimes, to ensure passing, they build the mock-up to a higher standard than will be used for the building. Sometimes, they test to easier conditions than the building will actually face. Sometimes they do both.

Sometimes they build the mock-up and don’t test it at all.

Tom recalled a multi-family condo in Northeast Portland (Oregon). The builders did a mock-up, then did everything possible to ensure it passed all the tests.

They used a window specially built just to pass the test.

Once the building was up, they confidence-tested the windows. The building had 300 windows. They tested random windows on each floor for air and water resistance. If the windows passed — like the mock-up — the test would end after 10 windows.

If a window failed, two more windows woud be tested, to restore confidence.

With 10 good windows, everyone could be confident most of the windows were good.

The only problem was that the window assemblies on the condo were not built to the special guaranteed-to-pass standards of the mock up.

The first window failed.

The second window failed.

Every window they tested failed. And they all failed in exactly the same place.

If the builders had tested a mock-up constructed with the same products and procedures used for the condo, they could have uncovered and corrected the problem immediately.

A fluorescein dye test reveals where these window assemblies will fail, and under what conditions. The problems can now be corrected before they occur in the finished building.

Instead, they bore the cost of replacing every window in the condo.

Testing should be to failure, not to artificially low standards. Design specification should consider actual geographic placement of the structure. Weather and surrounding structures have impact on what conditions the building will experience.

Typical ASTM tests are not adequate to predict the performance of the materials, assemblies or systems. Test committees do not often have construction experience.

Most testing is done under conditions the structure may never experience — 70 degrees Fahrenheit, 50 percent relative humidity.

You might think if you use the highest-quality proprietary materials backed by warranties, and install them strictly according to manufacturers’ instructions, those materials will all work as promised, and there will be no need to test.

You’d be wrong.

Product data-sheets will not indicate how the materials will perform in the presence of other materials.

Only preconstruction design verification testing will do that.

Testing doesn’t just save money by being more economical than repair. Constructing a mock-up under the same conditions, with the same people, products and procedures as will be used for the building confirms construction schedules and sequences. It helps determine labor costs, helps avoid pitfalls and educates everyone involved.

Meaningful design verification testing raises the level of expectation in performance of materials, assemblies and systems. When you know exactly, based on testing to failure, how far your materials can go, then you know exactly what you can expect from those materials.

That knowledge opens up opportunities for creative design, and results in energy-efficient buildings, better application methods, more cost-effective practices and healthier structures.

Anything less is a gamble at best.
# # #

Tom Schneider, BEI, shooting in Alaska

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