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Simply – Caulk

If you have been following the progress of Desert Rain house, by now you know it is not an ordinary construction process. From design, to materials, to building technique – the process is ‘above and beyond’ the standards in the building industry. Every detail is essential, including the caulking.

White lines of caulk filling the gaps in the sheathing helps minimize air infiltration.

Read About It! The Passive House Institute United States (PHIUS) is an energy consulting and research firm working to further passive house standards nationwide. www.passivehouse.us

Desert Rain is designed to be air tight, super insulated, and ‘passive’. According to The Passive House Institute United States, ‘The passive house concept, which can cut the amount of energy homes consume by up to 90 percent, has the power to dramatically reduce our energy bills and our global carbon dioxide emissions.’ To reach the goal of an air tight building, Desert Rain will receive a comprehensive, whole house caulk. This is currently apparent as the white caulking stands out against the wood surfaces of the exterior sheathing. Even the joints in the ‘bird boxes’ under the roof eaves have not been overlooked. This attention to detail will minimize air leaks, which is just as important as insulation and triple glazed windows in reducing heat transfer.

Above and Beyond – even the ‘bird boxes’ (framing under the eaves) are caulked, though the soffit boards will cover the framing also.

Infiltration of outside air is a major component of heat transfer between the exterior and interior of a house.  Air sealing, by caulking the exterior sheathing and framing joints, will minimize air leakage in the outer envelope of the house, increasing thermal performance.  While the primary role of insulation is to control the flow of heat, cavity insulation has little effect on air infiltration.  A combination of framing detail and air sealing by caulking will significantly decrease air infiltration. Simply caulk  –  with the potential to move Desert Rain toward the goal of being an energy efficient, draft free, moisture free,  and comfortable home.

Caukling lines showing on siding and above door.

Recovering Energy

The roof becomes ‘energized’.

I received a quick tour and introduction to the site by Jim Fagan of Timberline on May 22. In addition to being introduced to many of the contractors, I observed that the solar thermal modules had been installed on the roof on Monday. The seven panels are an integral component of the solar thermal system that will transform sunlight to energy to produce hot water and heat. (Please see the blog from May 15, for more information about the PV and thermal systems for Desert Rain.)

A close up of the solar PV module installed on the roof.

The Energy Recovery Ventilator (ERV) was being installed by Matt with Moore Climate Control, a local air conditioning and venting contractor.   (ERV) is the energy recovery process of exchanging the energy contained in normally exhausted building or space air and using it to treat (precondition) the incoming outdoor ventilation air.  An energy recovery ventilator features a heat exchanger combined with a ventilation system.  This type of equipment was introduced as “air-to-air” heat exchangers in the colder regions of the U.S. over ten years ago to pre-heat and control humidity in tightly built residential homes. During warmer seasons, the system pre-cools and dehumidifies. This technology has demonstrated an effective means of reducing energy cost and heating and cooling loads, with the benefit of improving indoor air quality.

Matt with Moore Climate Control works on the ERV system.

ERV is an ‘air to air’ exchanger that saves energy while improving air quality inside the home.

Coming up soon: pouring a nine inch thick concrete slab over the cistern, windows, stucco, and using some of that reclaimed pine lumber. I can’t wait!

 

Controlling Weeds the Natural Way: By Hand

Landscape contractor Chris Hart-Henderson, left, discusses options for removing annual ryegrass from the property. May 8, 2012.

I’ve talked before about the wood being used in the construction of Desert Rain–how it is all either Forest Stewardship Council (FSC) certified or reclaimed. To meet the Living Building Challenge (LBC) the project must not only incorporate, but must solely use materials that are “safe for all species throughout time” (LBC 2.0). Meticulous planning has ensured that everything–from the foundation to the roof and everything in between–will be non-toxic and equitably sourced.

Annual ryegrass growing on the Desert Rain site.

The same amount of concern for what goes into the Desert Rain environment applies to what’s being taken from it. Careful board-by-board and nail-by-nail deconstruction of the homes that previously stood on the site ensured that materials stayed out of the landfill and were put to reuse. Now Barb and Tom are faced with a new dilemma: what to do with the annual ryegrass that is quickly spreading along the west side of the property. It needs to be removed, but the question is: how?

Chris and Tom in the quickly growing ryegrass.

When faced with a wide area weeds, a too-common approach is to spray the area with a noxious weed-killer. But that obviously isn’t a solution when working on an LBC project, and it isn’t an approach Barb and Tom would take regardless. But the non-native ryegrass is a tremendous fire hazard and must be removed, and it needs to come out in order for other plants to thrive. To meet LBC standards, a dedicated percentage of the project area must be used for food production, and landscape contractor Chris Hart-Henderson’s plan incorporates service berry, elderberry, currants, wild strawberries, rose hips, Oregon grape, and choke cherries.

Barb and Tom met with Chris on the site on Tuesday afternoon. They pulled ryegrass as they discussed their options, which essentially are to try to smother it with a mulch or to pull it–and keep pulling it. With its wide distribution throughout the western portion of the site as well as in some rocky areas, it doesn’t sound like it’s feasible to smother it. So the answer is to pull. With constant maintenance, Chris says that it can, over time, be controlled.

Tom, Barb and Chris pulling the annual ryegrass as they discuss ideas for keeping it at bay.

Chris Hart-Henderson of Heart Springs Design.

Pulling annual ryegrass.

The ryegrass quickly piles up.

A visitor with a mild interest in the grass: a yellow-bellied marmot.

Once the grass is pulled it will leave room for edible plants on the site--as well as for tulips like these.

 

Why the Roof is the Foundation

It was a very blustery day in Bend today, with winds gusting up to 40 mph. But anyone who lives and works in Bend is used to the area’s quickly changing weather conditions–from 70 degrees and sunny one week to 50 degrees and raining the next. Rain or shine, snow or wind (or all of the above–completely possible on one day in Bend!), construction crews across town show up to work.

To the rear left you can see the roofing material now on the garage. To the right, the River Roofing of Bend crew is getting ready to place the steel roofing on the accessory dwelling unit.

The crew from River Roofing of Bend was on site at Desert Rain today, busy installing the metal panel roofing on the ADU (accessory dwelling unit). They completed the garage yesterday. To get video of the guys I climbed up onto the roof of the main home (you’ll find the video at the bottom of this post). You can really feel the wind from a rooftop! After an exhilarating hour up there, I climbed down to find a perfectly timed e-mail from Morgan Brown, president of Whole Water Systems in Seattle, Washington.

Whole Water Systems (http://wholewater.com)

Morgan is leading the way in engineering and managing Desert Rain’s water sustainability. Whole Water gathered more than two decades of rainfall data to develop a comprehensive water system–from rainwater collection (rooftops) to water storage (cistern) to water treatment (constructed wetland bioreactor)–that will allow Desert Rain to meet its water needs without having to rely on any water beyond that which is naturally available to it: rain and snow.

The roof design is an integral part of the home’s water use plan. In essence, it is the foundation of the water system. It is where precipitation first makes contact with the site, and, as a home being built to meet the Living Building Challenge, it is that water–and that water alone–that will provide for Desert Rain’s water needs. There must be enough roof surface area to effectively gather the needed precipitation. And determining roof area requires consideration of a variety of factors. Morgan explained the modeling used when calculating water needs for Desert Rain:

“Our engineer took into account the twenty year history of precipitation in Bend (average = 12 inches/year); lowest rain year (seven inches); amount of roof surface area available for collection; and range of anticipated user demand (occupants behavior, amount of water used). The resulting modeling suggested the need for a 30,000 gallon cistern to store enough water to get the occupants through the worst case dry spell without sacrificing on their intended average water use.”

Bear in mind that Barb and Tom’s intended average water use of 30 gallons a day per person pales in comparison to the national average, which is 98 gallons of water per person. Water conservation will come from a variety of areas, including Barb and Tom’s conscious behavior, high-efficiency plumbing fixtures, and a landscape that requires no irrigation.

The River Roofing crew installing the steel panels on the garage. May 2, 2012.

But to get the water we go back to where I started: the roof. “There are a variety of techniques that are employed to ensure the quality and sanitary nature of the drinking water collected from rain,” says Morgan. “First of all, the type of roofing material needs to be appropriate to assure that no unacceptable substances leach into the water.”

Jim Fagan, Desert Rain’s contractor with Timberline, said “It’s rolled steel from Kalama, Washington. They put an LBC [Living Building Challenge]-approved coating on it, and then place it on a big roll and deliver it to River Roofing here in Bend. And they actually fabricate the roof panels here. Steel is one of the things that LBC refers to as globally sourced. There’s a lot of recycled content in almost all steel now–there’s no virgin steel anymore. Steel is steel and we can get it from anywhere. But obviously if we can buy a coil of steel from somewhere in the Northwest, we’re going to stay close.”

This regionally sourced material serves to further the sustainability of the home and to create a dwelling that meets various aspects of Living Building Challenge standards, including respectful use of water.

I’ll close with a compelling quote from Morgan Brown about why water use and conservation is something we should all be thinking about–and why a standard like the Living Building Challenge is now more important that ever.

“From space, Earth appears as a water planet with two-thirds of its surface covered with the liquid. Unfortunately, this is saltwater and life on land requires freshwater to drink and grow the plants that produce our food. Of all the water on Earth, only three percent is freshwater and less than one percent is available to us in the form of rivers, lakes and aquifers that we can use to drink and grow food. To exacerbate the problem, we haven’t done a very good job of taking care of this one percent. With worldwide population at seven billion and climbing, we have been doing a miserable job of stewarding the finite resource we have available. Unlike oil and gold, we can’t live without freshwater. Necessity being the mother of invention, the near future will see drastic changes in how we use and value freshwater.”

– Morgan Brown, Whole Water Systems, Inc.

Video from the Desert Rain site today is included below. (Please excuse the wind noise; there was certainly no escaping it

Weekly Update – Week ending April 27, 2012

Specific construction concerns & LBC:
Construction continues at a good even pace. Kevin at Timberline has posted several more
materials and products to be vetted for LBC compliance. He emails ML when there are items with
a higher priority. ML reviews information on a regular basis and it is helpful to know what will be
needed for construction to continue without interruption or delay because a material had not been
fully vetted.
Health and Indoor Air Quality Testing
ML has been in contact with local energy analysts and air quality testers. James and ML will meet
on site with one of them next week. Jody Howe is BPI (Building Performance Institute) certified as
a Building Analyst and Envelope Professional. She may be able to perform the indoor air quality
testing needed for LBC compliance. It will be helpful to have someone local who can visit the
jobsite at significant intervals to test the building. James would prefer to have testing performed
after each major installation, such as after the building is completely dried in (i.e. after the windows
and roofing are installed) and again after insulation, and after cabinets and casework. By
establishing baseline measurements, we’ll be able to locate any potential problems and, hopefully,
pinpoint the source and remedy it.
Lighting
Wendy with Tozer Design has sent ML numerous (over two dozen) e-data sheets on selected light
fixtures. ML is working through the vetting process, checking them for compliance with both the
Red List and the Radius Sourcing requirements.
Constructed Wetland Bio-reactor
A third option for meeting LBC Ecological Water Flow Imperative has been proposed by Tom.
Graywater would be plumbed to the Constructed Wetland Bioreactor to be processed and recycled
on site for irrigation. Dehydrating toilets would be installed that basically desiccate human waste.
The units being considered only require maintenance every 2-6 months, depending on usage and
climate conditions. They need to be pumped, similar to a septic tank system. The team will
research thoroughly all the available options, particularly checking for reliability and ease of use.
No one wants to install a product that causes odor or maintenance problems.
ML will be conferring with water and waste experts at the Living Future Conference in Portland next
week. This international conference brings together green building leaders who are working on
Living Building projects all over the world. It is an excellent opportunity to discuss possible
solutions with others grappling with these same issues.
Construction Update:
Now that the weather has settled down a bit, the plywood protecting the window openings has
been removed. Framing continues on the interior and the roofing is beginning to add a new color
to the site. The Vintage gray fascia was being installed at the end of last week with the main
roofing to follow. The basalt rock base is also progressing nicely. The true color palette of Desert
Rain is starting to emerge with these various shades of gray from dark to light.