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Cordwood Construction: Best Practices 2012

The book Cordwood Construction: Best Practices is hot off the presses. It is written by long time cordwood builder Richard Flatau and is reported to be the most up-to-date tome on cordwood building.
Here are a few of the details.

Cordwood Construction: Best Practices

A log home building method using renewable resources
and time honored techniques (2012)

Authored by Richard Flatau

List Price: $25.00
8.5″ x 11″ (21.59 x 27.94 cm)
Full Color on White paper
196 pages
Cordwood Construction Resources
ISBN-13: 978-0615592701 (Custom Universal)
ISBN-10: 0615592708
BISAC: House & Home / Do-It-Yourself / General

259 color photos, diagrams and formulas will take the novice or experienced builder from house plans to cordwood home occupancy. Sections include: mortar mixes, R-values, code compliance, types of wood, drying wood, shrinkage tables, foundations, how we became mortgage-free, post & beam framing, formulas for estimating materials, homeowners insurance, Cordwood Conferences 2005 & 2011 summary, Best Practices with cordwood construction, lime putty mortar, cob, paper enhanced mortars, Permachinking walls, building codes, color photo album, making stained glass bottle ends, how-to “mortar-up” a cordwood wall, tuck pointing, FAQ’s, maintenance, weight of a cordwood wall, cost analysis, Cordwood Education Center, White Earth Reservation cordwood home, a condensed version of Cordwood Cabin is included (which is architecturally drawn and state code approved and now serves as a classroom for the local public school), 196 pages, and much, much more…

Here are two reviews of the book, one by Richard Freudenberger, editor of Backhome Magazine and the other by Rob Roy, Director of Earthwood Building School.

Excellent Up-to-Date Cordwood Reference May 8, 2012
By R. Freudenberger

This book by veteran cordwood builder and instructor Richard Flatau turns out to be one of the most comprehensive references available on cordwood construction. Flatau has put a lot of effort into the “Best Practices” studies, and as a result we all have the benefit of other builders’ experiences, much gleaned from his involement in organizing some of the large Cordwood Conferences held in the U.S. and Canada. All the basics are here as well for novice builders–foundations, framing, wood choices, mortar mixes, special effects, utility interfaces, and increasingly important code compliance. The book is full of illustrations, tables, a few floor plans, and lots and lots of good color photos. The bottom line is that cordwood masonry is cost-effective, energy-efficient, fire-resistant, and very sustainable…and it’s a perfect do-it-yourself endeavor for the owner-builder.
Book Review by Richard Freudenberger Editor of Backhome Magazine

Cordwood Construction: Best Practices … Richard Flatau CoCoCo/05 organizer (and long-time cordwood writer and builder) Richard Flatau has just published this new compendium, his best yet. True to its title, the author details “best practices” methods about cordwood masonry and its relationship to foundations, electrical considerations, energy codes and so much more. By themselves, two recent case studies (the Cordwood Education Center in Wisconsin and the Whole Earth Reservation Cordwood Home in Minnesota) are worth the price of this beautifully illustrated and meticulously documented work. 196 large 8.5″ by 11″ pages, including 259 color pictures and diagrams.
Book Review by Rob Roy Director of Earthwood Building School

Cordwood in Kenai, Alaska

This is Mark & Chelsea in front of their cordwood home in Kenai, Alaska.  The walls are 14″ spruce with foam insulation in the center cavity between the two 3″ mortar beads.

Here are more photos of their two story home.  They used a log wizard to craft the beams, posts and rafter.

Alaska provides ample solar time to work during the summer, but in the winter it can be a challenge.

Interior cordwood

Riding the wheelbarrow up to the second floor.

A final picture.   Nice job Chelsea and Mark.

Inspiration for future cold weather cordwooders.

Happy Trails,

Richard Flatau

Cordwood Construction Resources

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

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

715-212-2870                715-536-3195

Nauhaus Prototype Gets Plastered

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.

Nauhaus Radio Interview

radioMike Figura and I did an interview about the Nauhaus prototype with Ned Doyle for his radio show, “Our Southern Community”. Okay, the interview was in February and I’m just getting around to listening to it. I’ve been busy, so sue me.

Anyway, this is still accurate and has good information about our work, though some things have changed. For example, Mike now wears a tie.

Here’s the interview divided into two parts:

Nauhaus Interview Part 1

Nauhaus Interview Part 2


Nauhaus Primer: Talking Head About Carbon Neutrality and the Nauhaus Prototype

We recently recorded this video intended as a draft to help us work on our public spiel. It needs a lot of work, but I thought I’d post it anyway because it’s a fairly thorough introduction to what we’re doing generally and the prototype in particular.  Just pretend you’re in high school and lunch is next period…Go generic sports team with some sort of mammal as its mascot!

Carbon Neutrality and The Nauhaus Prototype from Clarke Snell on Vimeo.

We've Got Windows

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!

Legalize Industrial Hemp Nau

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:

Building Fundamentals: Energy Efficiency Geekout – Anatomy of Windows and Doors Part I

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

If you ask 10 kids to draw a picture of a house, I can almost guarantee that they’ll all include a door and at least one big window. Ask those same kids 25 years later to describe their dream houses and I predict they will all be crammed full of windows. What I’m saying here is that in my experience, we all love windows. What’s wrong with that? Well, if our goal is to create an energy efficient building, typical glass-filled openings are actually a real pain in the astragal because compared to modern wall systems they perform horribly. In this month’s column, I’ll explain the basics of why this is true. Then next month, I’ll tell you what you can do about it.

Sidebar: R-value vs. U-value

Resistance to heat flow in building materials is usually quantified as R-value. The higher the R, the better the insulation. Just to confuse us, the insulation value of windows is expressed as U-value which is the inverse of R. To find out the R-value of a window, divide 1 by its U-value. For example, U= .4; 1÷.4 = R2.5

Heat Loss

Other than keeping rain and snow out of your bed, perhaps the most pivotal function of your house is its ability to create a different temperature inside than the temperature outside. This is accomplished by wrapping the interior space with insulation, a generic term for a material designed to resist the flow of heat. To oversimplify for our purposes, the better this insulation cocoon functions, the less heating or cooling the building will need. Since heating and cooling both cost money and usually involve global warming creating carbon emissions (our buildings are responsible for about 50% of our collective carbon footprint), improving insulation has been a focus of the green building movement. In recent years, we’ve made incredible strides and now have access to insulation systems that can produce walls systems with R-values (see sidebar) in the 20’s, 30’s, and even 40’s. Typical new windows, however, have R-values of only 2 or 3, 10 or more times worse than the wall itself. This is almost equivalent to a thermal hole in the wall. Therefore, the main performance flop for windows is their inadequate resistance to the flow of heat.

Mean Radiant Temperature

Mean radiant temperature is basically the average temperature of the surfaces of everything in the vicinity of your body. In a house, that means the surface of windows, walls, furniture, dusty knickknacks, and everything else. All of these surfaces radiate heat outward toward your skin, and your skin in turn radiates toward them. Since windows are so bad at slowing heat movement, their surface temperature will tend to be very different than that of other surfaces in your house. If the surface temperature of an object near you is considerably less or more than that of your body, you feel it as cold or warmth. This is why on a cold winter day, the thermostat can read 70F and you’ll still feel cold standing by a window. Low surface temperature, then, is another way windows drag down the overall thermal performance of our wall system.

Air Leakage

Doors and operable windows are basically huge holes that can be opened and closed. By definition, though, that closure is never perfect. The hole always leaks. Gaps and cracks in our wall will allow air to bypass insulation resulting in the movement of heat in or out of our building. Therefore, another strike against windows and doors is their contribution to this air leakage.

Solar Heat Gain

Responsible energy efficient designs incorporate a basically infinite, free source of energy: the sun. In our climate this means letting the sun in during the winter.  We need glass-filled openings to accomplish this. Different glass types and configurations let in more or less of the sunlight that hits them. This is quantified as a number called the solar heat gain coefficient (SHGC) which is basically the percentage of potential solar heat that glass lets into the building. For example, a SHCG of .5 means that 50% of the potential solar heat is making it through the glass. There are situations where we want solar heat gain and others where we don’t, so the wrong glass type in the wrong place can be a major detriment to building performance.


The point I’m making here is that windows and doors are typically VERY weak spots in the performance of a modern building. Next month, I’ll give you the skinny on how to choose the right windows and doors for new construction and remodeling or how to spiff up the performance of your existing underachieving glass units.