Posts regarding ‘Systems’

Cordwood Hobbit Style House with round door and living roof in Wisconsin

August 23rd, 2010 by Strongwood

Dan and Jessi P. built every hairy footed hobbit-fanciers dream home.  A 16 sided cordwood home (in Wisconsin,) complete with post and beam framework, living roof, masonry stove/heater/bake oven, stained concrete floor and a round, green hobbit door.

The work is artistic, attractive and very nicely done.  The bottle end  and cordwood walls are artistic, attractive and very well done.   The nasturiums on the floor add a touch of whimsy.

Here is a quote from Jessi’s blog.

“We’re proceeding apace with the walls, which look so lovely when they’re done – from a distance they look like stone. Labor intensive and messy, but beautiful. We also have the framework for the round green door done. So we’re looking hobbity!”

Jessi ends her emails with the following quote:

Not all who wander are lost.   J.R.R.Tolkien

Here is another quote from Jessi.

Subject: Cordwood House

Hi Richard – glad you like the looks of our place! All told, if you count the tree cutting/peeling summer, it took us about 5 years, but the actual cordwood stuff we squeezed into about two and half months – we started in October and laid up the last bit of wall the second week in December two years ago with the aid of much tarping and space heaters . It’s sixteen sided on a floating slab. The logs are 18 inches with loose fill insulation in the cavity. They are a mix of hemlock, spruce, and red pine which we took for the most part off the property. Our masonry heater was done by Gimme Shelter Construction over by you and then faced by a local mason, Wayne Kostka. Don was partially right in his comment – even on the coldest days this winter we were comfy with two fires a day, and it has stayed cool enough this summer that we haven’t bothered to move the window air con over from our old house. The roof is 6-8 inches of dirt over an Enkadrain drainage layer. Sedum we put in last fall has spread nicely and we put in another couple pounds of cuttings this summer, so in a few years when we’ve worn out the weeds it should be a nice low maintenance roof. All the rain we’ve had this year has given it a good test

To Jessi & Dan:

Kudos, congrats and thank you for sharing your wonderful cordwood home.

Richard Flatau

Cordwood Construction Building School

flato@aol.com

715-212-2870                715-536-3195

http://www.daycreek.com/dc/html/dcrflatau3.stm

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Nauhaus Prototype Gets Plastered

July 13th, 2010 by Clarke

Exterior and interior plastering is underway on the carbon neutral Nauhaus prototype.

The interior surface of the hempcrete walls has a base coat of earthen plaster consisting of sub-soil harvested from the construction site and mixed with sand and water. The mix was chosen after testing sixteen different compositions, a process spearheaded by intern Shannon Levenson. Earth plaster serves the Nauhaus prototype mission because it requires almost no energy to make or transport, and therefore has very little carbon emissions associated with it. In addition, earth plastering is fairly easy to learn, requires few tools, and is instantly gratifying, both because it’s beautiful at any skill level and very similar to playing with mud pies, a therapeutic experience that many adults realize they have been neglecting for too long. Whatever the reason, the earth plastering process attracted volunteers and interns like flies to…well, compost.

The exterior wall surface has been covered with a base coat of lime-based plaster supplied by Lime Technology as part of the hempcrete wall system. Both interior and exterior plasters were applied directly to the hempcrete which proved to be an excellent plaster substrate. Fiberglass mesh, similar to mesh drywall tape, were embedded in plaster over any joints or cracks in the hempcrete. Together these plasters over hempcrete create a vapor permeable wall system, sometimes called a “breathable wall”. The idea is to create a wall that is open to taking on and giving off water vapor in response to humidity levels in the air inside or outside the building.

We believe vapor permeable walls will last much longer and help create better indoor air quality than cavity wall systems that dominate US residential construction. As any builder will tell you, it’s pretty much impossible to keep water out of walls. Permeable walls are designed with the idea that it’s okay if some water gets in as long as it can get out just as easily and won’t cause any damage in the process.

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We’ve Got Windows

May 26th, 2010 by Clarke
A quadruple pane window from Serious installed in a hempcrete wall in the Nauhaus Prototype

A quadruple pane window from Serious installed in a hempcrete wall in the Nauhaus Prototype

Well, we finally got the windows and doors installed. Okay, let me vent for a sec: prototypes are a bitch. We had to do a lot of head scratching and trial and error to figure out the best way to insure airtightness in our installation. The hempcrete is awesome, but it create its own set of challenges, especially since our truly wonderful Serious windows aren’t really designed to be installed in the middle of thick walls. (Serious is a partner with us on this project and we’re working with them to make things easier when you decide to replicate what we’re doing.)

First, let’s sing the praises of these windows. Though a number of German companies make windows in this category, Serious Materials is the only US company that can meet the required specs for a Passive House. All window and door units on the project have fiberglass frames and quadruple pane glazing. Southern glazing has a center of glass insulation value of R-7 with an impressive solar heat gain coefficient (the percentage of solar heat that passes through the glass, 1.0 would be 100%) of about 0.7. This allows for heat gain from the low southern winter sun, a strategy integral to the Passive House integrated design system.

North, east, and west glazings weigh in at an amazing center of glass rating of R-11, a rating equal to the fiberglass insulation in some conventional stick frame walls! This is compared to R-2 for a typical double pane window found on most US projects. Unlike the heavier European windows, Serious reaches this performance level with two pieces of glass and two pieces of plastic allowing for a thinner profile more like conventional windows typically available in the US.

Why all the fuss? Well, I’ll tell you. In a Passive House in our climate region, walls need to be about R-40.  Sticking an R-2 hole in an R-40 wall just doesn’t make sense.  In a Passive House, the idea is to spend money on passive elements, extra insulation and really good windows for example, that don’t require energy inputs to do their job once installed, unlike heating, cooling, and ventilation equipment. In the right configuration, these passive elements combine to allow for a much simpler and less expensive mechanical system, thus saving money in construction and afterwards with much lower energy bills.

Anyway, we’ve got video footage that we’ll eventually compile into a bunch of great educational how-to videos on the ins and outs of all this nifty construction detailing. If anyone out there is getting antsy for the goods, getting us a grant to fund collation of the documentation footage would really speed things up. Until then, wet your chops on these few photos:

Here you see our custom plastic lumber sill piece with groove for backer rod and space for spray foam, the edge of the bituthane sill pan (green stuff), and the poured in place concrete exterior sill

Here you see our custom plastic lumber sill piece with groove for backer rod and space for spray foam, the edge of the bituthane sill pan (green stuff), and the poured in place concrete exterior sill.

All windows had to be pre-drilled through the fiberglass frames...

All windows had to be pre-drilled through the fiberglass frames...

...then screwed to the stud framing in the middle of the hempcrete wall.

...then screwed to the stud framing in the middle of the hempcrete wall.

Jeff installs backer rod as part of a multi-step installation process to insure maximum airtightness

Jeff puts his engineering degree to work installing a backer rod as part of a multi-step installation process to insure maximum airtightness

The plastic lumber sills were filled with foam after installation through a series of pre-drilled holes...ingenious!

The plastic lumber sills were filled with foam after installation through a series of pre-drilled holes...ingenious!

Southwest view showing all the windows installed. Doesn't look like any big deal, does it?

Southwest view showing windows installed. Doesn't look like any big deal, does it?

Installing the doors was a whole different story...don't get me started!

Master carpenter and benevolent genius Tim working on a door. Installing the doors was a whole different story...don't get me started!

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Legalize Industrial Hemp Nau

May 20th, 2010 by Clarke

Well, it’s Hemp History Week.  Here’s the short version of the industrial hemp rant:

If you think the US is a capitalist country, think again. We can buy all the industrial hemp products we want, but we can’t grow the raw material to make the products ourselves. Can you say, “trade imbalance”? To learn a bit more, watch these two short videos we were involved in that discuss industrial hemp generally and then specifically as it applies to our Nauhaus prototype:

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Building Fundamentals: Engineering Fundamentals

April 22nd, 2010 by Clarke

This interview by Clarke Snell was originally published in the New Life Journal.

I moved to this region about 15 years ago because I thought it would be a better place to set up a homestead. I was looking for mountain spring water and milder temperatures than my Texas home. I found both, but the longer I’ve been here, the more I’m amazed by the people who live here, especially the ones I meet in my work in the world of “green building”. For my next few columns, I’m going to interview one of these local founts of wisdom on some aspect of all things green. This month, I talked with local mechanical engineer Jeff Buscher:

You and I are old enough to remember that ancient time before “green building” was a household word. How did you first get involved in the field?

I was studying architecture and engineering at Kansas State University when I read the book “Ecotopia” in an elective philosophy class. I remember it as a turning point for me. I started focusing on energy efficient technologies and sustainable practices in whatever way I could. After graduation, I worked for a large commercial engineering firm in Dallas for a number of years. It was frustrating because I kept pushing for sensible energy efficiency measures, putting them into designs only invariably to have them taken out at some point due to shortsighted reasoning, such as short-term construction cost reductions over long-term operating cost savings, let alone considering the additional environmental benefits. I finally decided to put my money where my mouth was and move to a smaller firm identified with green principles.

You and I have been working together for a while and I’ve come to really value your perspective. You’re unique in my experience because you combine an expansive knowledge of complex technology and technical methods with an interest in simple technologies, such as those commonly referred to as “natural building”. Given that novel perspective, what do you see as the important issues for “green building” enthusiasts to focus on?

First of all, we’ve got to face reality. The conventional construction world is in the grip of two dangerous forces: ignorance and inertia. Ignorance because efficiency has only been a concern for one generation.  We’re all still learning the best way to do this, but frankly, many building professionals aren’t educated as to even the most basic, common sense issues of building science. Inertia because to make money and avoid getting sued it makes sense to keep doing the thing that worked the last time. In other words, the construction industry is wary of innovation and slow to change. Real innovations tend to come from small companies that are light on their feet and driven through passion to do interesting things. Even in the “green building” industry most people are content to build to code. Forget codes. Building to code is the bare minimum acceptable to avoid being fined for breaking the law. To get where we need to be, we should be building at least two times in excess of current code mandated insulation levels. By achieving that level of performance we can significantly downsize or eliminate heating and cooling systems and make zero net energy buildings financially feasible. [Note: Zero Energy Design (ZED) can be defined as designing buildings that produce as much or more energy than they use.] ZED has been possible and achieved for decades. It’s not technically all that difficult to do.  It’s rare because it requires more design effort, and with current solar prices it costs a little more up front.  However,  the long-term benefits are huge. The question today is whether we can afford not to do it.

ZED is just barely starting to make it onto the mainstream radar. I think to a lot of people it sounds like something out of a science fiction novel. Can you shed a little light on the steps to move from conventional construction practices to ZED?

Well, it’s true that there is some high-tech involved, but many of the steps are old school. These concepts have been around for millennia.  First, we start with the land. Maximize what you can get from the building site and the surrounding area. Work with the sun for passive solar heating and cooling. Collect water on the site. Use as many materials from as close to the site as possible. Next, we need to stop building these light, expendable, giant boxes that pass for houses, office buildings, malls, what have you. We need more insulation and more mass. Insulation is a common concept for most people, but mass not so much. Adding heavy, dense materials (mass) adds to temperature stability and longevity of a building. This is a common approach in Europe, but we’ve missed the boat here.

In our climate, by creating a highly insulated building, you can drastically reduce the heating load, and by using a lot of mass you can potentially avoid mechanical cooling to keep the building comfortable. When compared to complex mechanical systems, insulation and mass are inexpensive and, once installed, they don’t require any additional input of energy to do their job. Past a certain threshold of load reduction, current “alternatives” such as solar electricity (PV), wind generators, solar hot water, and waste heat recovery start to become the sensible default solution rather than a luxury. This is where engineering becomes pivotal. Through energy modeling and integrating systems design with passive aspects of the building’s performance (insulation, mass, solar heating and cooling), we can create buildings that require only a fraction of the energy and resources to build and run compared to present common practice in this country.

The single variable that has the most effect on a building’s energy and resource efficiency is it’s size, so another major component of this strategy is to build smaller. Finally, we have to stop looking at our buildings as islands and start seeing them in their social context. A small, energy efficient eco-cottage is still missing the point if it’s part of a lifestyle that requires a two hour daily commute. Mixed use. Co-housing. Go local.  Live where you work.  Eat where you live. We should be designing to make driving less convenient and walking, and biking more convenient. I’m a big fan of the New Urbanism movement and recommend that people read up on it.

I’m with you on all of this, but one thing that makes me a bit nervous is our increasing dependence on complex technology. I’ve always been a do-it-yourselfer, but now I find myself spending more and more time in front of a computer whose inner workings are a complete mystery to me. That makes me fundamentally uneasy. What’s your take on the possibility of taking technology too far?

Obviously, that’s a danger. However, my personal feeling is that we need to find a way to solve our environmental problems while maintaining some level of the “comfort zone” that modern humans have become accustomed to. Technology can be a very useful tool in that context.  For example, in our climate, humidity is extreme. Around here, there is no way to create stable indoor humidity levels without some level of mechanical equipment. For me, the fun is in finding ways to limit and simplify the technology required to solve problems like this. I’m working on it, and I know others are too, so stay tuned.

To find out more about what Jeff thinks about, check out his blog at www.thinkorthwim.com and check out these sources of information that he recommends:

  • Walkable towns:  www.ecotownz.co.uk
  • Andrés Duany’s talk about how to avoid suburban sprawl:  www.youtube.com/watch?v=Ysoth-DYs78
  • ZED Architects in the UK:  www.zedfactory.com
  • Passive House Institute:  www.passivehouse.us
  • The Living Building Standard (No credits, just prerequisites.  It’s about what you did good, rather than being about what you did less bad.):  http://www.cascadiagbc.org/lbc
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Firewood: Don’t Burn It, Build With It

April 22nd, 2010 by Clarke

This article by Clarke Snell was originally published in the New Life Journal.

Western North Carolina is becoming an incubator for green and natural building. As far as green building goes, homes built to Healthy Built Home standards have skyrocketed. We’re also well stocked with the latest cutting edge technologies and building concepts. For example though they were rare only five or ten years ago, you pretty much can’t shake a stick without hitting a hydronic in-floor heating system these days. Solar hot water is WAY back in, too, I’m happy to say. On the natural building side, it’s a real smorgasbord around here. We’ve got a number of code approved straw bale houses in several area counties. I know of two Earthships (a housing system that uses old tires packed with dirt as the wall system) in good old Madison County for god’s sake. We’ve got some cob, adobe, clay-slip straw, and the other earth/straw permutations around, too, though they seem to be more often built below the code radar than not. Conspicuously absent from our collection has been cordwood construction….until now. Toby Crawley and Maria Muscarella are nearing completion on a code approved cordwood house in Leicester. Let’s check it out.

What is Cordwood Construction?

Cordwood is firewood: air-dried, unmilled wood cut to length. Cordwood construction (often called “cordwood masonry”) is a technique for building walls with firewood. In the most basic approach, sticks of wood are placed in two beds of mortar separated by a space, usually several inches wide, which is then filled with some kind of loose insulation such as sawdust or vermiculite. (PHOTO). There are many possible mortar mixes. One popular mix contains sand, wet sawdust, lime, and Portland cement. Another uses lime and sand. Another paper pulp. Yet another simply clay, sand, and straw (cob). Cordwood walls can be designed to carry roof loads or they can be installed in combination with some form of post and beam structure. Since wood can shrink or swell, species and drying time are variables that are often debated by cordwood enthusiasts.

Cordwood Pros, Cons, and Performance

Pros: If you live in the forest, then the main advantage of cordwood is obvious: it’s an abundant, locally available, affordable building material. If you choose to go with a cob mortar and sawdust insulation, you could collect almost all of your wall volume from your building site. That’s saying something these days! In addition, laying cordwood requires only basic tools and simple skills. Once laid, cordwood walls require no additional finish such as drywall or wallpaper with sea shells on it. (Note: I’m only talking about the cordwood portion of the construction here. You still need a foundation, window and door framing, a roof system, heating and cooling strategies and systems, and all the other things that make a house a complex animal.)

Cons: Laying cordwood is a lot of hard, physical work. It also takes a lot of forethought in terms of cutting and drying the wood. (It’s a good idea to let cut and split wood air-dry under cover for at least a year before using in a wall.) In addition, the exposed end-grain of each piece of wood facing toward the exterior is susceptible to water infiltration and therefore mold, insects, and other damaging forces. Good design such as a proper foundation and good roof overhangs can go a long way to solving this issue. For me, perhaps the main functional cordwood con is wood shrinkage which can cause gaps and cracks that lead to air infiltration and even separation of cordwood from the mortar.

Performance: Comparing cordwood’s thermal performance to a more conventional wall system is difficult to generalize and beyond the scope of this column. However, I will say that since cordwood is made on site, it’s thermal performance can be adjusted to suit the specifics of the house project it is serving. The thicker the wall, the better it will resist the flow of heat, so you can theoretically generate the performance you need by adjusting wall thickness. In colder climates, an option for increasing thermal performance is double wall cordwood masonry, a system employing two cordwood walls separated by a space filled with insulation. Wood is both a decent insulator and a good thermal mass, so it is competent at both resisting heat flow and holding heat. Another potential performance plus for cordwood is it’s hygroscopic nature…it’s ability to take on and give off water vapor in response to changes in humidity levels. This trait theoretically helps wood to balance indoor humidity levels and therefore potentially improve indoor air quality.

Toby and Maria’s House

As someone who has been hangin’ around the natural building water cooler for a number of years, I have to say that I’m always skeptical when I hear about the next wave of novice owner builders taking a shot at home construction. Sometimes it works out great and sometimes…well it’s a disaster. I’m happy to report that Toby and Maria are doing a good job and look like they are going to make it through intact. In my opinion, their secret to success has been (1) an initially somewhat realistic budget and (2) the financial flexibility to go well over their initially somewhat realistic budget.

After doing their research and checking out a variety of options, Toby and Maria chose cordwood over other “natural” building options because they thought they could muster the skills and reasoned that cordwood could pass code in the area. This turned out to be true probably mainly because they chose a post and beam structure with cordwood infill. The post and beam construction was stamped by a structural engineer leaving the cordwood infill with no official structural role. They cut cordwood from poplar harvested on their property and bought most of the rest of the framing lumber from a local mill. They salvaged hardwood floor from a dumpster (it looks great!) and bought most of their doors and windows from Habitat for Humanity.

The approximately 1,400 square foot building is 16-sided and roughly circular. It will have a living roof planted with sedums. The north section of the first floor and the small second floor are wood framed and insulated with Icynene spray foam leaving roughly the east, south, and west areas of the first floor in cordwood. Though they are hooked up to and existing well and septic system and have a flush toilet, Toby, Maria and family plan to continue using their sawdust toilet and composting their humanure for use in the garden. (Yeah, baby! See my rant against flush toilets in other of my writings or just stop me on the street to get an earful.) They have hydronic in-floor heating fed only by solar collectors, i.e. there is no boiler back-up and therefore no petroleum based fuel input. The back-up heat source is a high efficiency wood stove. Last, but not least, they are using Earthpaint finishes throughout the building. (If you don’t know about local paint and finish manufacturer, Earthpaint, get with it already!)

If you want more information, Toby and Maria have graciously agreed to supply a contact email address (tcrawley@gmail.com). They still have some cordwood to lay, so get in on the next cordwood party! As for me, I’m always looking to deepen my knowledge of the local natural and extreme green building scene, so don’t hesitate to send me leads and contact info for interesting projects at clarke@thinkgreenbuilding.com. Until next month, keep it green.

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Is Wood Good? A Look at Burning Wood for Heat

April 22nd, 2010 by Clarke

This article by Clarke Snell originally appeared in the New Life Journal.

It’s winter, so I’m thinking a lot about wood. That’s because it’s a major strand in my life-line this time of year. I’m lucky enough to live in a house that is heated by a combination of direct sunlight and wood collected basically from my back yard. In a world that I am increasingly unable to grasp, it’s always a centering, empowering experience to warm myself with wood that I’ve cut, split, and hauled with my own hands.

A sensible question, though, is whether it’s environmentally responsible to burn wood for heat. The preamble to an answer to this question is that the “green” approach to heating has to start with a very well-insulated, weatherized building that maximizes the heating potential of the sun through passive and active solar design (see last month’s column for more info). These strategies will greatly reduce the amount of extra heat we’ll need in the building.

With that said, there are two basic environmental issues to consider: management of natural resources and pollution. As a resource, wood is both locally available and renewable. When you compare fighting wars over dwindling oil reserves to taking a chainsaw into your back yard, wood seems the clear winner. To my mind, IF (and this is a big IF) the wood is harvested in a sustainable fashion, then burning wood is a smart choice from the point of view of natural resource management.

That leaves the question of pollution. Is wood a clean burning fuel? The answer depends on how you burn it. To understand what I mean, we need a quick science lesson. (Full disclosure: I am not a combustion scientist, nor have I played one on TV.)

Combustion or “burning” is the chemical reaction between a heated substance (fuel) and oxygen. In the case of wood, there are three stages of combustion. In the first stage, wood heats up to the point that interior moisture turns to steam. This process actually consumes heat, so we are no closer to warming our feet at this point. With the water gone, though, the wood can get hotter and begins to vaporize releasing gases, better known as “smoke” to us laypeople. If the temperature is hot enough, this smoke will burn releasing heat in the process. After the gases have been released, what’s left is called “char” which is basically a pile of almost pure carbon. In the presence of enough heat and oxygen this carbon will combine with oxygen to produce carbon dioxide and release more heat.

Carbon dioxide?! Isn’t that a greenhouse gas that contributes to global warming? Yes, it is. The fact is that all types of combustion (whether coal, oil, gas, etc.) produce carbon dioxide. However, there is a difference. Trees take in carbon dioxide as they grow. When they die, fall, and decompose in the forest, they expel this carbon dioxide. If you burn wood, that same carbon dioxide is released, so theoretically there’s no global warming difference between letting wood decay and burning it. (The reality is, as usual, a bit more complicated, but, hey, remember I’m no combustion scientist.) On the other hand, the CO2 released from burning petroleum is CO2 that plants took in millions of years ago and has been sequestered all that time in the ground. Therefore, burning petroleum brings additional CO2 into the picture, and consequently contributes to human induced global warming.

If we accept this carbon dioxide argument, then how clean wood burns and how much of it’s potential energy is converted to heat is simply a function of how completely it combusts. If smoke is allowed to float away without combusting, the result is creosote and a bunch of nasty particulates that can pollute indoor and outdoor air. If the “char” doesn’t completely combust, the result is unburnt char and by-product carbon monoxide which as we all know is a poisonous gas. To avoid these environmental pitfalls, we need to (1) create enough heat and (2) contain the fuel.

Wet wood is the enemy of creating heat. A lot of energy is wasted burning off water which keeps temperatures low and therefore allows smoke to escape without burning.  The first step, then, regardless of stove type is to use well seasoned (dry) wood. Next, we need enough oxygen. Campfires burn well because they have access to plenty of oxygen. The problem is that the fire is on the bottom while vaporizing gases quickly rise away from the flames, therefore a lot of fuel just floats away unburned. We need to contain those gases in a heated environment so that they ignite after they rise away from the flames. Next, after the gases have burnt off, we need to keep burning the char hot enough to make sure minimal carbon monoxide is created. Finally, we have to find a way to store most of the heat off of this now incredibly hot, efficiently burning fire. If not we’ll quickly overheat our house.

Since we are geniuses, humans have created stove designs that solve these problems. In my opinion, the best of these are generically called “masonry wood heaters”. Though there are a number of variations, the basic idea is to burn wood hot and fast in a stove made of dense masonry materials (brick and stone) that then can absorb the heat and slowly release it into the house over many hours.

My favorite design is the “contraflow heater”. In this stove, wood is stacked log cabin style in a tall firebox made of firebrick with ample air intake basically creating an enclosed campfire. As smoke rises off the fire, it is confined and therefore compressed in a secondary combustion chamber where it ignites. Hot air from this combustion leaves the chamber at both ends and then travels back down the sides of the stove in channels created by another layer of brick that surrounds the stove. The air then enters the bottom of the chimney and moves out of the house. The brick soaks up much of the heat from the air as it travels up and then back down through the stove. Meanwhile back in the firebox, the char continues to combust in an environment of ample air and heat. After a couple of hours when combustion is complete, the stove damper and air intake is closed to prevent air movement out the chimney and the stove then slowly radiates its stored heat into the house for up to 24 hours. The result is an extremely efficient burn with very low particulates and a comfortable, even radiant heat.

As with all things, there are downsides. For one, masonry heaters are expensive and heavy, requiring a solid foundation to sit on. They also require a lifestyle adjustment over conventional heating sources. They heat up slowly, so you have to plan ahead if the stove has cooled down. In other words, no cranking up the thermostat when you get home from work.

Luckily, other wood stove technologies approximate the advantages of a masonry heater. New metal stoves have advanced catalytic combusters and/or ingenious air intake and injection strategies. Some metal stoves incorporate soapstone or other mass to allow for some amount of heat storage.

On the other hand, as I said earlier, there’s a bad way to burn wood. Metal stoves that are two large for the space or poorly designed require that you starve the fire to prevent overheating. Smoldering a log in an old damped down cast iron stove creates massive amounts of particulates and only turns about 25% of the wood into useful heat compared to 75% or more for a masonry stove. A roaring fire in an old-school fireplace is even worse, turning an estimated 0% (yes, you read that right) to 15% of the wood fuel into useful heat. If you’ve got an old metal stove, either modify it to include an air to air heat exchanger (here’s a link to show you how: http://www.aprovecho.org/), or get rid of it. Sell it for scrap or use it for yard art, but don’t pass it on to another user. If you are buying a metal wood stove, make sure that it is EPA approved (labeled EPA II).

To learn more about masonry wood stoves, check out the Masonry Heaters Association of North America. Their website is http://mha-net.org/html/library.htm. To further research metal wood stoves, first peruse this government website (http://www.epa.gov/woodstoves/index.html) so that you can impress your local wood stove dealer with some intelligent questions.

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Building Fundamentals: Renewable Energy, a Discussion with Ole Sorensen

April 22nd, 2010 by Clarke

This article by Clarke Snell was originally printed in the New Life Journal.

When we meet with clients in our office for the first time to discuss their desires for a “green” house design, they seldom talk about pivotal but boring things like insulation levels or conscientious weatherization detailing. In fact they very often know very little about what might make the house itself “green”.  Invariably, though, they do discuss alternatives to conventional energy production. Solar electricity, hydronic in-floor heating, and solar hot water are almost always mentioned. That’s a good thing because our buildings are responsible for the lion’s share of our societal energy use and consequently play a huge role in our present pollution and environmental degradation problems. To help us all get a bead on our energy use options,  I sat down recently with Ole Sorensen of Solar Dynamics, a renewable energy system design and installation company based in Asheville.

Most of our clients say they want to take advantage of alternative energy technologies, but in my experience few know what that really means. What is “alternative energy”?

I try to stay away from the word “alternative”. To me “alternative energy” is coal and propane. In the final analysis, the only energy sources that make sense, the ones that need to be our primary sources, are those that can be part of a sustainable lifestyle. My ultimate goal is sustainability. A sustainable energy source is one that can be continually renewed. In other words, things that we don’t have to worry about running out of. As it turns out, almost all renewable energy on this planet comes from the sun. Every ½ hour enough energy from the sun hits the earth’s surface to power human civilization for a year. In other words, we don’t even need to be efficient, we just need to commit to tapping this basically infinite resource in it’s various forms.

The most basic solar energy is direct sunlight which can be used to heat buildings through passive solar design. Direct sunlight can also be used to heat water or some other liquid to create domestic hot water and energy for in-floor hydronic heating. We can also turn that same sunlight into electricity using photovoltaics. Wind-power and hydro-power are also forms of electricity whose power source is the sun. The sun heats air to, in combination with the rotation of the earth, create wind. The sun also evaporates water to create rain and other precipitation, the force that creates a constant cycle of falling water on the planet. We use both wind and falling water to turn turbines that create electricity. The energy held within ocean waves is another largely untapped source of solar energy that is starting to be commercialized for electricity production.

There is constant and exciting innovation in the world of renewable energy technology. However the tech stuff is only half of the equation to creating a sustainable approach to energy. The other part is lifestyle adjustment. Billy Jonas has an environmental song that my kids and I love that repeats the line, “It all comes from the groun-duh.” It’s a basic and profound point. All we have is this one earth. Duh. We simply have to find a balance between what we take and what we leave behind. I’ve seen statistics claiming that if everyone lived like we do in the US, we’d need five planets. Talk about unsustainable!

This is a point that really scares me. I know that we in the US are out of control in terms of our energy consumption and then it seems like the rest of the world is frantically trying to catch up with us. There just isn’t enough planet to go around. How do you see us getting out of this mess?

To illustrate let me tell you a story from my own life. I’m from Denmark and started out in a highly academic environment. I then decided to move into boat building. I couldn’t get my fellow classmates to approach the process academically. We had a hard time communicating. My teacher pointed out to me that my classmates and I were talking two different languages and asked me the question, “Who would have the easier time changing their language, you or them?” I realized that it was up to me to bridge the gap because my background gave me the skills.

I see our present energy and environmental problems in the same way. The rich industrialized countries are the ones using the most energy and creating the most pollution. We’re also the ones with the technology and resources to find sustainable solutions. It’s up to us to solve this problem, to change our language so to speak. Rather than having poorer countries struggling to catch up to us in our present consumption patterns, which is simply impossible, we can show the way for them to utilize renewable energy to prosper sustainably. The concept is not that hard to grasp. We are the ones who have the knowledge and are using the excess. It’s up to us to create enough for others. The wonderful thing is that we actually have the know-how to make this happen if we have the will.

As someone who has lived in this country almost all my life, that’s a little hard to imagine. Our whole paradigm is based on trying to get ahead, seemingly at any cost. How do we go about changing the paradigm. How do we go from being the problem to solving it?

We are already in the middle of the paradigm shift. It’s you and I and all our fellow citizens who create change and most people today want sustainable energy. There is a demand for it. The problem is that in many cases the solutions are not available to everyone because they are too expensive. Since I got into this business, PV (solar electric) panels have gone from 12 to 20% efficiency. In other words, panels now transform into electricity 20% of the solar energy that hits them. That’s an amazing technological improvement in a short time, but clearly there is a lot more energy there for us to capture. We simply need more research and development money to reap even greater improvements in efficiency that will allow prices to come down even further. If we really got behind renewables, put our money where our mouth is so to speak, we could be getting a lot more and paying a lot less.

Another problem is one of scale. As with most things, the smaller the system, the more you pay per unit. PV is just too expensive for most people to put on their houses right now, that’s why most PV installations are commercial. It’s the same with wind power. Commercial wind companies won’t even consider a project unless it’s in the 10 to 20 million dollar range. Smaller and the economics just don’t add up. I think we need more options than simply residential and large commercial. We need community and neighborhood renewable power plants, large enough so that they are affordable but not so large that we necessarily have to wait for the large power companies to get on board.

Countries with high percentages of renewable energy, Denmark for example produces about 20% of its electricity demand from wind, are doing things like this. They have some residential and apartment buildings, but also a lot of larger commercial projects. Germany has a single PV array covering the equivalent of 11 soccer fields. Another array stretches more than ½ mile along the highway to the Munich airport. Germany made a very conscious decision in the 1990’s to go solar. To put it simply, people there were willing to pay more to move toward sustainability and that created the political will to get the government involved. That’s what we need in this county. We need to step up to the plate in support of renewables and then hold our government accountable to make a meaningful transition to renewable energy.

Okay, so far you’ve been talking about the big picture which is of course very important, but it can also be a formula for inaction because we tend to feel overwhelmed with the scale of the problem. It seems that thinking globally and acting locally really fits in this context. You started your business to be part of the solution and your solution is making renewable energy available to residential customers. How does someone go about making renewable energy a part of their daily life, in other words a part of their present or planned house?

When someone comes to me, the first thing we do is discuss their dream. Every situation is unique and depends on a client’s energy consumption, square footage, sun or wind exposure, budget, and current tax credits. Honestly, people almost always begin with dreams of a lot of technology, then we start talking price and many people back off. We then look in their budget for the thing that will make the biggest difference. I like to look at it in terms of a “sustainability budget”. You budget for other things, why not sustainability. Let’s say you have $15,000 in your sustainability budget. In other words, you want to invest $15,000 now in moving toward energy sustainability. You’ll get this money back in utility bill savings over time, but it’s an upfront expenditure. What’s the best way to spend that money?

Well, energy production isn’t the first thing to consider. That’s my dilemma as a renewable energy installer. I need to keep in business, but I also have a responsibility to the planet and society. So when someone comes to me with limited funds, I tell them first to reduce their energy needs by building smaller and by creating an efficient building envelope, in other words installing more insulation and paying attention to weatherization. Next, I tell them to choose construction methods that will create a long-lasting durable building that won’t require a lot  of maintenance. Then we talk about reducing energy usage because the less energy you use, the more affordable your renewable energy system will be.

At this point we’re ready to talk about energy. Let’s go back to the original example of a modest $15,000 sustainability budget. My suggestion would be to spend $8,000 for additional insulation and $7,000 for a quality solar hot water system. You’ll get more bang for your buck this way than spending the $15,000 on a solar electric system. Don’t get me wrong. I applaud and support clients who make a commitment to PV. I’m just realistic that for the majority of people right now there are more cost effective ways to get the same positive environmental effects. If a client can’t afford PV, then my “best of both worlds” solution here is to install solar hot water and plan for an eventual PV system by putting in conduit and other inexpensive infrastructure as part of the initial construction process. If the budget just really can’t support even solar hot water, we can also install transmission lines in the wall and take other steps to make the eventual installation easy, efficient, and more cost effective. In my opinion, a solar hot water rough-in should be as important as a front door in new construction.

What about hydronic in-floor heating. Why do you install these systems?

Hydronic heating can use either radiators or can be set in a slab or under a floor. These systems, especially the in-floor variety, are sustainable because they are incredibly efficient. The boilers I use are 97% efficient and don’t require energy hog fans as with air source systems. In addition, hydronics can easily utilize direct solar radiation as a heat input. The same solar hot water heating system we’ve been discussing can do double duty as a heat source for your radiant heating system. In my opinion, hydronic heating has the lowest environmental impact of any heating system available, including burning wood. Of course, a big selling point for hydronics is comfort. In-floor hydronic heat creates a wonderful, mellow heat that doesn’t dry the air or make noise while it’s running.

One of the common complaints I hear about renewable energy systems is that the exposed machinery is “ugly”. What’s your response to that criticism?

Personally, I can get ruthless when it comes to aesthetics. If the most efficient car in the world looked like a piece of cheese, I’d drive a piece of cheese. Of course, as a company we are sensitive to and try to accommodate the aesthetic needs of our clients. To give solar panels as an example, at our latitude and with most roof pitches, it is going to be more efficient to raise roof-mounted panels at an angle to the roof. However, sometimes customers want their panels to lie flat on the roof because they feel it looks better. If our analysis tells us that this will result in only an insignificant reduction in system efficiency, we’re happy to do it. If, on the other hand, that isn’t the case, then we feel the need to stand our ground and install the panels at an angle to the roof. In the end, this always results in a much happier customer. We have to hold on to the big picture: our goal of sustainability. If it means getting over a perception of what you consider to be ugly, then so be it.

Here’s another example. One of our wind power customers had a hard time convincing his neighbors and the press that the wind turbine he planned to install wouldn’t be an eye sore. It wasn’t until we finished the installation that they realized what a simple, eloquent machine this was and not as huge as they imagined in their minds. One journalist even apologized and wrote a second positive article about it. Education is the key. When people complain about how ridge-top wind-power systems will adversely effect their “view shed”, I tell them that there won’t be a view shed without wind-power. In the last few years, there has been a marked deterioration in air quality even in our rural area. That’s not haze, people, that’s smog.

I like to say that sustainability and denial are archenemies. They just can’t work together. We have to decide to let go of our denial and embrace sustainability. To contact Ole and for more information on Solar Dynamics:

Phone: 828-665-8507 or 828-231-9106

Email: ole@solardynamicsnc.com

Web: http://solardynamicsnc.com

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Cordwood Education Center on the cover of Backhome Magazine Jan/Feb 2010

February 5th, 2010 by Strongwood

There is a fine photo of a team of Percheron’s pulling a sleigh on February 14, 2009 in northern Wisconsin on the cover of Backhome Magazine (which is published in Hendersonville, NC.)
www.backhomemagazine.com

The Cordwood Education Center in Merrill, WI

The Cordwood Education Center in Merrill, WI

There is a 3 page article entitled Community Constructed Cordwood which details the volunteer labor used to build and then donate this 850 sq. ft. building to the local school system. The cordwood building is constructed using Best Practices and Energy Star Guidelines.  There is more information at

http://www.daycreek.com/dc/html/cordwood_education_center.html

To read the complete article go to:     http://www.daycreek.com/dc/pdf/Backhome_104.pdf

A recycled bottle end (stained glass) wall at the Cordwood Center.

A recycled bottle end (stained glass) wall at the Cordwood Center.

Richard Flatau

Cordwood Construction Resources

Merrill, WI

flato@aol.com

www.daycreek.com/flatau

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The Latest in Prototype News

January 22nd, 2010 by snugganut

For the last couple weeks, Matt and his crew, plus volunteers, have been continuing the second floor Hemcrete installation.

If you’re interested in volunteering for the Nauhaus Prototype Project, please contact Billy.

Click here to view the entire Nauhaus Prototype Construction Chronology.

Current View of Southeast

Current View of Southeast

Current View of Southwest

Current View of Southwest

Hemp Stacked and Waiting

Hemp Stacked and Waiting

The Trusty Mixer

The Trusty Mixer

Ben is the fastest Hemcrete installer in the West!

Adam is the fastest Hemcrete installer in the West!

Support for the upper forms on the North side.  The black landscape fabric covers the CMU blocks, which will be beneath grade.

Support for Upper Forms over CMU Wall

Closeup of Form Attachment

Closeup of Form Attachment

Scaffolding

Scaffolding

The forms are built up almost ot the overhangs, and are stuffed by hand.

The forms are built up almost ot the overhangs, and are stuffed by hand.

Completed Window Opening

Completed Window Opening

Thermally broken mounting bracket for roof supports.  The pink is foam insulation.

Thermally broken mounting bracket for roof supports. The pink is foam insulation.

Closeup of Hemcrete in Form

Closeup of Hemcrete in Form

A combination of custom and pre-made forms is used on the 2nd floor.

A combination of custom and pre-made forms is used on the 2nd floor.

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