Little house; big promise

This artist’s rendering shows“Detached Accessory Dwelling Unit” Mini-B placed in its typical intended setting.

Mini-B is a tiny little thing.

It stands for “Mini-Bungalow.” It’s a prototype 300 square-foot “Detached Accessory Dwelling Unit.” In the Seattle area, you can plunk it down in your back yard for a guest house, or for grown-up kids who need to stay with Mom and Pop for a while.

Though small, it has a kitchenette, three-quarters bath (shower but no tub), living/dining room, bed loft, closet, equipment loft with storage, solar hot water collector, and vaulted ceiling.

It conforms to the International Residential Code and is considered a “modular” building in the State of Washington, says the building’s designer, Architect Joe Giampietro, Johnson Braund Design Group, Seattle.

Mini-B is built to an energy conservation standard that uses as little as 10 percent of the heating energy used by similar houses built with traditional methods and materials. It’s a conservation standard that can slash heating bills up to 90 percent.

When the last inspection and test is completed, Mini-B will be certified a “Passive House” by Passive House Institute US.

Passive houses are well-insulated, almost 100 percent air-tight, and they provide plenty of fresh filtered outdoor air at all times. They’re heated by passive solar gain, by heat from people and electrical devices. You can get additional heat if you need it, by more traditional means, but you’ll only need a little.

Because Passive Houses are well-insulated and extremely air-tight, a little heat goes a long way. Heat energy loss is small.

Power use is so low that with a small photovoltaic array to generate power, you could easily make the Passive House carbon neutral, Joe says.

There are a few Passive Houses in the U.S., and over 20,000 in Germany and Austria. The Passive House idea took root in Europe after originating in the United States. It began here in the mid-80s as a way to achieve energy efficiency via super-insulation, airtight construction, high-performance windows and heat-recovery ventilation Joe says.

Students in Seattle Central Community College’s Wood Construction Center are building Mini-B. It’s mostly complete as of October 2010, Joe says, with the students finishing up interior details.

Mini-B wears its breathable, durable, seamless, continuous air & waterproof barrier, as it waits for installation of fiber-cement lap siding.

The completed Mini-B will go on display for six months at Seattle’s Phinney Neighborhood Association center. After that, Joe says, it’ll go on the market, and more will be built for sale.

Mini-B’s air tightness – the building envelope’s ability to limit heating and cooling losses via air leaks – will help buyers recoup their investment through drastically reduced energy bills, says Joe.

Mini-B achieves much of its extreme level of air-tightness via PROSOCO’s fluid-applied R-GUARD FastFlash System. This air and waterproof barrier was originated by PROSOCO’s business partner BEI (Building Envelope Innovations), Clackamas, Ore.

Its four components address every possible way a building envelope could leak air. When heated air leaks out into winter cold, of course, it carries energy dollars with it. When hot summer air leaks into air conditioned spaces, it increases the load on the HVAC system.

In both cases, the warm air carries water vapor. If, on its way in or out, that warm air hits a chilly-enough surface, the water vapor it carries condenses. That provides moisture, an essential ingredient for mold, Joe explains.

By stopping the air leaks, the FastFlash system reduces the chances of mold developing in the walls. Since the FastFlash system is vapor-permeable or “breathable,” it can let small amounts of vapor exit the building envelope – in other words, if walls do get wet inside, they can dry out again.

Sealing the structural walls begins with filling all joints and seams – major air leak points — with R-GUARD Joint & Seam Filler. It goes on like caulk, but tools and spreads like a coating, with a knife, trowel or spatula.

The next step is sealing the structural framing of the rough openings for doors and windows with R-GUARD Fast Flash. Like Joint & Seam Filler, Fast flash is a sealant-like, yet spreadable waterproof detailing compound.

Heather Bryson, Wood Construction Center Student, applies a spreadable sealant to the exterior of a rough opening in Mini-B.

It was a good choice, said Frank Mestemacher, the instructor at Seattle Central Community College who supervised the students constructing Mini-B.
“I’ve used fabrics and adhesives to seal rough openings,” he said. “To seal them tight, you have to overlap the material. That gives you a buildup which makes it hard to fit the windows into the rough openings. Usually the material gets torn, which defeats the purpose of the barrier.

“The liquid flashing we used gets into all the cavities, knots and joints, and seals the rough opening up tight.” Frank said. “But you get nice neat corners that make it easy for the window frame to go in.”

When dry, the flashing is also durable and self-sealing, so the tears and scrapes associated with fabrics and adhesives don’t happen, Frank said.

Then, the entire wall assembly gets a roller-application of R-GUARD Cat-5 primary air and waterproof barrier. Cat-5 takes its name from the fact that, though breathable, it seals structural walls against air and water ingress in weather conditions from normal up to and exceeding a Category 5 hurricane – even before the cladding goes on.

The students rolled it on over the plywood panels as well as the filled seams between panels. Cat-5 ties the entire assembly together in one seamless, continuous coating, which is what you’ve got to have to stop air leaks through the envelope, Joe said.

Cat-5 also serves as a secondary drainage plane, in case water gets through the cladding.

All three components are instantly waterproof, so you can apply them to damp surfaces. That means no delays due to rain, usually a major advantage in the Pacific Northwest, though Joe said rain wasn’t much of a factor during construction of Mini-B.

The fully flashed rough opening on Mini-B’s right elevation waits for installation of the window frame.

The fact that these components bond tenaciously to structural walls wet or dry was also important, Frank said.

“I’ve seen paper wraps where the wind just tears them away from the building before the cladding goes up,” Frank said. “We liked these products because they adhere.”

Once the window and door assemblies were in place, the students used R-GUARD AirDam, interior sealant used with backer rod, to seal the space between frames and rough openings.

The inside corner of this window shows the rough-opening red sealant flashing, and the white air dam, used with backer rod, which seals the gap between frame and rough opening.

The weather-tight seal keeps expensively conditioned air from escaping through gaps between the frame and rough opening. It ensures water from outside is diverted to flashing, and outside air can’t leak in.

The fact that the FastFlash system doesn’t rely on layering like tapes and building papers do is huge, Joe says.

That air-tightness makes it possible for the HVAC system to efficiently do its job of frequently exchanging used inside air for fresh outside air.

That was verified in July when energy auditors conducted a calibrated blower-door test.

This test uses a powerful front door-mounted fan to pull air out of the house, and measure how much air gets pulled in through leaks in the building envelope. It verified Mini-B meets Passive House standards of .60 Air changes per hour at an air pressure of 50 Pascals.

That’s about one tenth of the air-changes in a typical house, Joe said. That’s because the fresh air in the house does not come through the wall, but through the full time ventilation system.

“A ‘house that breathes’ is another way to describe the Passive House,” Joe said. “It breathes vapor through the walls like our skin, and air through the ventilation system like our lungs.

As energy costs soar, Passive House and other energy-efficiency concepts are gaining greater traction, Joe says. He points to a recent “Passive House” article in the New York Times; Passive Houses in Vermont, Illinois and Washington; and increasing numbers of Seattle-area construction professionals who are adopting Passive House-type concepts.

“For me, one of this project’s biggest benefits has been learning to apply the principles of low-energy and high-performance,” Joe said. “Placing windows appropriately for solar gain; specifying high-performance windows; stopping air leaks through building envelopes; installing heat and energy recovery ventilators — these and other ideas can be used individually or together to improve performance and energy efficiency in any building.”

It’s a new approach, driven by ever-increasing fuel prices, he said. For homeowners, it holds the promise of taking fuel prices right out of the household budget equation – or at least putting them in a more affordable perspective.

That’s one big shining promise, embodied in one very compact house.
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Easy with that wand, Eugene!

Too much water pressure in too tight a stream scarred this newly laid concrete brick wall.

I just got this pic from Manufacturer’s Rep Jeff Lucas, of J.N. Lucas & Associates, Hammond, Ind. Jeff got called in by the brick’s manufacturer to see if he could figure out a way to fix the damage.

The building is new masonry construction — a civic center in Indiana. That red brick is made of concrete, not clay. The problems occurred when the mason contractor tried to clean off the job dirt and excess mortar. That’s standard procedure, but the contractor missed the boat on several points, according to Jeff, who’s been in the biz nearly 30 years.

The contractor’s main error was that he didn’t realize concrete brick is more sensitive than clay brick. He had the right kind of masonry cleaner, Jeff said, but ran into trouble with the pressure rinse.

Once the cleaner has “dwelled” for the prescribed time — usually a few minutes — and dissolved the excess mortar and job dirt, you rinse it off with a pressure washer. That’s where the problems happened. The contractor, or his workers, hit the masonry with a solid stream, zero-degree fan tip, at about 2,400 psi. That’s a virtual laser beam of water.

You can see where it cut through the surface of the brick, exposing a darker subsurface. That’s why the scars are less apparent where the bricks are darker. You may have also noticed the white residue covering most of the wall. That’s where the cleaner dissolved excess mortar, like it’s supposed to. But the contractor didn’t use enough water to fully flush the spent cleaner and dissolved mortar from the wall.

When the wall dried, it revealed the chalky white mess you see in the photo. Jeff said the pressure washer used was a home model, equipped for only about 2.5 gallons a minute. A job like this takes closer to 6-8 gallons a minute. When it comes to flushing spent cleaner and the dissolved contaminants it carries, success is more about gallons per minute (gpm) than pressure per square inch (psi).

It’s more about how much water you put on the wall, and less about how hard you hit it. You get all the pressure you need at 400 -1,000 psi, with a 15-degree fan tip, minimum, and are much less likely to leave your initials in the masonry.

Particularly when working with concrete masonry, which is more sensitive than clay, reduced pressure is important. But I’ve seen clay masonry scarred just as badly by youngsters getting right up on the brick. In those cases, there’s not much that can be done, outside of replacement.

Here's another shot of the wand-damaged concrete brick.

Fortunately for this contractor, Jeff says the damage is repairable. He tested some samples and found that by scrubbing the brick with another dose of cleaner, and thoroughly rinsing, he could remove the thin surface layer that had been scarred. That will once again reveal the dark brick color created by the manufacturer.

It’ll be a lot of work, but the contractor should count himself lucky. He could’ve been liable for replacing the whole thing.

You can learn more about the fascinating subject of cleaning modern masonry by downloading my white paper on the subject – New Rules for new-construction clean-down of contemporary masonry buildings. It’s free. You don’t have to give us any information or anything. Just hope you find it helpful or at least interesting.

Might have saved that contractor some grief.

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The World comes to PROSOCO

PROSOCO President David W. Boyer explains the test chamber to Lawrence Journal World Reporter Christine Metz.

The World came to PROSOCO, Oct. 1 — the Lawrence Journal World, our local newspaper, to be exact.

Journalist Christine Metz, photographer Mike Yoder and videographer Steve Jones represented the award-winning newspaper and its sister TV news operation, Channel 6 News. They arrived to capture the story of our new “Hurricane in a Box” test chamber newly delivered from Florida.

Christine’s story, which I thought was excellent, ran in the Saturday morning edition. I’m only now getting around to blogging about it because I’ve been away for five days, chasing a freelance story myself in Virginia’s Blue Ridge Mountains.

The chamber, 10 feet tall, about 30 feet around, and 12,000 pounds, lets us test building envelope components like structural sheathing, doors and windows for air and water leakage under conditions from typical to in-excess of a category 5 hurricane.

Ron Tatley, the chamber's inventor, tells Christine, Steve and the Channel 6 News audience about the Test Chamber before firing it up.

Christine interviewed our company president, David W. Boyer, and the machine’s inventor, Ron Tatley of Building Envelope Innovations (BEI), Clackamas, Ore. BEI and PROSOCO recently joined forces in the effort to help create more durable, energy-efficient building envelopes — also known as “walls.”

We’ll use the Transportable Design Verification Chamber, or “Hurricane in a Box” in several ways.

1. We’ll test our own air & water-resistive/waterproof barrier products vs. the other products on the market.
2. We’ll use it to train our technical and sales folks on the features and advantages of our products, as well as comparisons and contrasts with other products.
3. We’ll test structural sheathing, windows, doors and other building envelope components for their manufacturers. Most of these components are required to comply with certain standards. So we’ll let them bring engineers from their preferred testing laboratories to witness the testing and sign off on it under their own letterhead.
4. We’ll offer a similar service to design professionals. For instance, we can slowly ramp up pressure in the chamber to show architects at what point their wall and window designs will begin leaking air and admitting water in severe — or ordinary — weather conditions.

That could help them avoid some unpleasant surprises. What’s more, these services will help educate the industry about how wall components can and should work together to make energy-efficient, mold-resistant and long-lasting building envelopes, er, walls.

And that’s news.

Steve gets a lens-full of the gear for the Channel 6 News viewing audience.

Ron Tatley makes some adjustments to the Transportable Design Verification Test Chamber before turning it on.

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