Archive for the ‘Extreme Weather/Earthquake’ Category

Climate’s Affect on a Bale House

There’s no question that your local climate will have a large affect on your home, whether it be a bale home or a home made of concrete block. In fact, the climate is often a driving force in people’s decision to build with bales. I’m sure you’ve heard people talk about how hot their climate is or how cold it is and how if they only had a more efficient home, they could better stand the extremes. Unfortunately, some people decide to build a straw bale home before they consider the potential affects that their climate could have on it until its too late. It’s important to know what might happen to your home before you build it because there may be steps you can take to minimize those affects if you plan ahead.

Below are some of the affects that climate has on a bale home. Some of these may seem obvious while others may not. I’m sure I’ve missed some, so feel free to add your own in he comments section.

  1. Rain can saturate walls if they are not properly protected. You may have heard the saying “Big Hat and Big Boots” referring to a good roof overhang and a large raised foundation. These are two very good ideas if you live in an area with high rain totals. Also consider adding a waterproof membrane above the bales, just below the bale stop or box beam. The challenge is avoiding punctures in this membrane during construction. Make sure it laps over the edge of the bales a couple inches. Too little overlap and water can still make it down into the bales. Too much overlap and your plaster will not adhere to the bales at the top of the wall.
  2. Humidity, unlike rain, cannot be designed out of the equation with a hat and boots because it permeates everywhere and it can cause moisture to build up in the walls if not handled properly.  The best approach to high humidity is two-fold. First, build with quality materials that can help in removing excess moisture from your air/wall interface. Hygroscopic plaster such as lime or earth is a great idea as it will naturally help keep a constant moisture level in the wall. If there is excess moisture in the air, it will absorb it and hold onto it (until it reaches saturation of course). Once the air dries out below the level of what the plaster is holding, the plaster will release the excess moisture back into the air. The second approach is a mechanical one. Install an Energy Recovery Ventilator (ERV) to help keep the air in your home fresh and to remove excess moisture. These are simple to install and work very well. They are also very energy efficient. Don’t rely solely on them as anything mechanical can fail (power loss, broken parts, etc) so be sure to use them as part of the two-fold approach.
  3. Cold weather can have all kinds of impacts. One that is often overlooked is the condensation of moisture in the walls. Because cold climates require us as humans to heat our indoor air space to stay warm, we create uneven climates from one side of a wall to the other that are quite drastic. If the warm and moisture laden air from the inside of the house pushes into the center of a bale wall where everything is cold, the moisture can condense on the straw. The best way to win this battle is to not heat your home and live in the cold. Not very likely option I suppose, so another plan of attack is to make sure you seal any penetrations into the wall and seams between the wall and other surfaces. The most common areas are around electrical and plumbing installations and at the floor to wall and wall to ceiling transitions. Be sure to pay special attention to these areas and you’ll be fine. Use foam gaskets at the electrical and plumbing installations and vapor tape and/or caulking at the wall to ceiling/floor transitions.
  4. Hot climates pose their own set of issues. Of course, hot climates that are associated with high humidity must be approached in accordance with #2 above; however, dry climates have a different set of concerns. One that is often not considered is the life of the plaster. Natural plasters are not built with chemicals designed to help them resist cracking and thus must be installed carefully. Be sure to plaster the house when it is protected and ONLY then. Hang tarps from the eaves so that you can plaster in the shade and out of the wind. These two aspects of a hot and dry climate can ruin a plaster job. Keep in mind that your plaster is not only the “look” of your house, but also its protection. If it is compromised, so too is the substrate, in this case, your bales.

Like I said at the beginning of the post, this list is in no way complete. There are many other climates that should and will be considered and many other affects of each of those climates. This is a list to do one thing: get you thinking. I hope it does just that. As always, I welcome your comments and input.

Tennessee Couple Loses Home to Tornado and Rebuilds With Straw Bales

Jill Plumer and David Clark were married 10 years ago and soon after the joyous occasion, began dreaming up plans for the home in which they planned to spend the rest of their lives.  They decided on a beautiful timber framed house design and eight years ago, the construction process began.  David is a carpenter, and for those years, the couple tenderly built their home, even felling their own trees to create the timber, while living in a trailer on the property to be close to the build.  The home was nearly done and they planned on moving into it this fall.

Unfortunately, Mother Nature had other plans in store.  On April 27, 2011, the tornado sirens seemed to go all day long.  In Chattanooga, where Jill works as Human Resources Director for the YMCA, there were 5 warnings and staff spent much of the day shuttling members down to the tornado cellar.  Jill made the decision to stay on site for the night to help remaining, rather than drive the 45 miles home to their property.  Upon telling David this, he agreed whole heartedly, noting that it wasn’t worth the risky drive to make it back to their land.

Meanwhile in their trailer home, David lay down to sleep, unaware that life as he knew it was about to change.  To say that David’s survival is a miracle is an understatement.  In fact, no words can truly describe or explain what happened that night.  As a mega EF4 tornado barreled down on their property at 9:28pm, David found himself at the mercy of fate and the paper-thin walls of his trailer.  In no time, the roof and walls tore away around him, flying into the surrounding woods and landing as a tangled web of twisted debris.  In the end, the only remaining unharmed object was David.

The tornado passed and David found himself outside in the pitch black of this horrific night, cold and battered by the driving wind and rain that consumed the landscape.  During the tornado, David’s emergency flashlight had been tossed into oblivion, leaving him with nothing but the sporadic flashes of the lightning storm to light his way.  He was disoriented by the darkness as well as the devastation of his property.   He turned in circles, looking for the house they had spent the last eight years building.  To his disbelief, he finally realized that he couldn’t find it because it no longer existed.  The home lay in complete collapse.  The next day they would see that the tornado had been so powerful that it had flung the four principal trusses, each weighing 1.5 tons, up to 50’ from the structure’s original site.

Sadly, others weren’t so fortunate, and that night Jill and David lost not only their dream home but also friends, neighbors, and some of their alpacas.  Jill shares that she and David have been affected greatly by this sad turn of events.  Going through this experience has been a major turning point for both of them.  They are touched and moved by the outpouring of support they have received from people in their small community; people with nothing extra to spare, showing up at their property, chainsaws in hand asking, “How can we help?  Where do you want me to start?”  They are deeply grateful for how embraced they have felt and are not taking an ounce of this generosity and kindness for granted.  They are even more committed now to rebuild their dream home as soon as possible so that they can start giving back.  David and Jill have no intentions of moving away and plan to remain in this amazing community for a very long time.

Since the tornado, the couple has been moving from place to place, staying with friends while they figure out how to rebuild on their land.  Recently they stayed with an artist friend, Frances McDonald, in Chattanooga, who is the first person to have built a straw bale home in the area.  Jill and David were so taken by their experience of staying in the straw bale home that Jill says, “There’s no way I can build a conventional home after living in a straw bale for a week!”  They love the look and feel of straw bale construction and are amazed that during their stay, when it was so “beastly” hot outside, whenever they came into the bale home, it was like stepping into a “cool, dry cave.”  They’ve been bitten by the straw bale bug and recently contacted us about hosting a straw bale workshop to build the Applegate Residence on their beloved property, which we will do from September 22-28.

There remains a lot of clean up on their land, once heavily forested and now littered with fallen trees.  Friends and family are still coming in from out of town to help in the clean up process and slowly but surely, things are getting done.  Stories such as this remind us of the fragility of our lives here in this beautiful and sometimes harsh world, where have no control over the elements and can only rely upon the generosity of friends and neighbors in times of great need.  We wish Jill and David all the best and look forward to being a part of their rebuild.

To read a newspaper article that was written up shortly after the tornado about David and Jill’s experience, click here.  To find out more about the workshop to rebuild a home for them with the Applegate Residence, click here.

Handling High Winds

If you live in a coastal area or mountain region, you probably have more experience with big wind gusts than someone living in a quiet little valley (except for those screamers that whip down the valley from time to time). The point is that wind is different wherever you go and building codes reflect those differences. Some areas in the United States, like Florida, Texas, and other Southern Coastal states, have to design their homes to withstand hurricane force winds while areas in Tornado Alley have to build their homes to handle twisters.

Picture: BNPS
This morning I was looking through the internet in search of facts about straw bale construction and high winds and I was shocked to see that the hard data is far and few in between. This seems to be an area in which some studies have been done, with promising results, yet little follow up and publications exist. I hope that I am wrong with this assessment and that, in fact, there are studies and papers out there that I am missing. To that end, if you have any leads I should follow up on or if you know of specific resources in regards to high wind/straw bale studies, please let me know. The following is what I was able to discover and, like I said, it is very promising.

Several years ago wind tests were performed on a straw bale wall in a wind tunnel similar to that described on the Nordic Wind Tunnel website. The test placed the equivalent of a 75 mile per hour gale force wind on the wall. In order to pass the test, the subject wall was not allowed to move more than 3/8″ from its original position. In the initial testing, the wall passed and, in fact, it did not move at all.  The test crew increased the wind load up to a gale force wind of 100 mph. Even with the increase in speed and force, the straw bale wall performed really well, moving only 1/16″, far below the limits provided for in the test.

In Serious Straw Bale, a book by Paul Lacinski and Michel Bergeron published in 2000, reference is made to a study performed in conjunction with the Canadian Mortgage and Housing Corporation (CMHC) in which hurricane force wind loads were applied to a test straw bale wall panel. The findings suggest that straw bale walls are vastly superior to conventional walls in resisting wind loads. The results showed that the panel withstood wind loads of 153 pounds per square foot (psf). This means that the straw bale panel could be rated at more than seven times a standard hurricane design load. That’s impressive!

As amazing as this all sounds, I think we need more. I would like to see more research done on the strength of straw bale walls and their ability to withstand high winds. We are seeing bigger hurricanes, more often here in the United States, and no one would likely deny that the same is true for tornadoes.  We may be sitting on a building technique that can protect thousands of people from the forces of nature and yet we are not in a position to take that technique to those who need to hear about it because we don’t have the scientific testing to back up our claims. It doesn’t matter how amazing these structures appear to be. We need to know without a doubt that they are as great as we believe and the only way to convince the “powers that be” in the construction world is through independent testing.

I offer you a call to action. Are you in a place to take part in that testing? Are you a professor or someone else with access to a wind tunnel? Do you have grant writing skills and/or the desire to headline this effort? There are so many things I want to do to increase the popularity of straw bale construction around the world, but I realize I just don’t have the time or ability to do them all. That’s why I’m asking for your help. If we can get the right people together and the right resources lined up, we can make this happen. It’s possible that the results of our efforts will help save lives in the future.

Straw Bale Construction in Earthquakes

I am not going to use pictures in this post as we all know what the recent devastation in Japan looks like. I want to start by sending Gabriella’s and my love, prayers, thoughts, and hope to all those effected by the recent earthquakes in Japan and New Zealand.  Clearly the tsunami in Japan was behind the majority of the death and damage, but the impact that earthquakes are having around the world on human populations cannot be missed. As is often the case with deaths associated with earthquakes, the housing in which people live can either be the shelter they so desperately need or a deathtrap.

Over the years, many people have looked long and hard at how straw bale structures perform in earthquakes. From the early pioneers such as Bruce King (who identified the seismic resistance qualities of straw bale construction) to the recent work done by Darcey Donovan (who spearheaded the shake table study at the University of  Nevada, Reno) these engineers and many others like them have long touted straw bale construction as a smart choice in earthquake prone areas. Let’s take a look at why.

  • Shear Design. When building post and beam structures, the most commonly utilized straw bale design, the frame itself is braced to resist lateral shear. Lateral shear is the force that is applied to a building in the same plane as the wall it is being applied to. In other words, if you stand at the corner of a building and push, you are applying lateral shear force to the wall you are pushing. The frame itself will be engineered to resits this shear force as the primary defense.
  • Redundant Design. The bales, attached to and notched around the framing, act as secondary shear resistance. This “backup system” adds significant strength to the overall wall assembly.
  • Natural Structural Insulated Panels (SIPs). The bales and the plaster are joined as one during the construction process. The combination of the two materials makes a natural SIPs panel which is amazingly strong. It is the combination of the rigid plaster skins with the soft bale interior that makes this structural assembly extremely strong.
  • Wide Footprint. The bales are wide, much wider than a conventionally framed wall, and as such, they have a wider footprint onto which they can spread any load applied during an earthquake.
  • Soft and Supple. The bales respond to seismic forces differently than conventional construction materials. In most of the conventional construction systems used here in the United States, the materials are designed to resist external forces (wind, earthquakes, etc…). Bales, on the other hand, are very good at simply absorbing those forces. Their ability to move, even in the most subtle ways, allows them to deflect much of the energy that would otherwise cause failure in rigid building materials.
  • Stronger Sills. I always use 4×4 sill plates/toe ups. These thicker, stronger boards are able to resist more force than a single or even doubled up 2x board. This is often the difference between a structure holding firm and breaking away from its foundation. (Another potential cause of such a failure is too small of a washer on the anchor blot itself, but that’s another story).

It’s important to remember in construction that a building acts as a unit. In other words, you cannot think only about the shear strength of the walls or the ability of the roof to resist winds. When wind pushes up on the roof, the roof wants to lift off of the walls and the walls want to either go with the roof or collapse into the home. The connections at every point through the house have to be considered and built to withstand the forces that can and will act upon them.

I’ve heard from many people who live in straw bale homes that their properties have done well in earthquakes. There are a lot of engineering numbers out there to support this idea too. Like I said earlier, a lot has been done to understand just how safe a straw bale building can be. I, for one, would like to hear more as we see the level and intensity of earthquakes increase.   If you know of any other studies of value, please let me know. I plan to undertake a comparison study in the near future testing the strengths and differences of post and beam bale walls, load bearing bale walls, and conventionally framed walls.  If you are interested in helping out with this, please let me know. I already have an engineer on board, Nabil Taha of Precision Structural Engineering, Inc. He is very excited and passionate about this project and straw bale construction in general. We are looking for help finding funding, most likely by means of writing  a grant request. In addition, we would love to have some people who are excited about this idea on board to help with all the many details that will arise from the project. Exactly what that means, I don’t yet know! Please leave a comment here if you are interested in helping in any way or if you know of other folks currently working on a similar project/study. Thanks.

Please Consider Donating to PAKSBAB

Gulzar’s family members had been feudal tenants for generations and living in a tent since the 2005 earthquake.

Last year they moved into their very own straw bale house and all of the children are attending school for the first time!

I recently received an update from PAKSBAB, the Pakistan Straw Bale and Appropriate Building in which Darcey Donovan, the CEO of PAKSBAB, describes the incredible good they have been able to accomplish in the world in the last 5 years. I love hearing positive news and trust that you do too, so I have attached her email here. Please consider supporting this amazing movement either by donating to PAKSBAB directly or, if you would prefer to send your money to a non-profit organization, you can send it to Builders Without Borders, who is a sponsor of PAKSBAB’s work. More infomration on how to do either of these things is below.

I hope you will at very least read about what wonderful things they have accomplished in the last 5 years and share their story with those you know and love.

Here’s the email I received…

I’m writing to you today to ask you to make a much needed donation to Pakistan Straw Bale and Appropriate Building.
One of my favorite books “Good to Great” discusses the flywheel effect, a series of cumulative small steps that build one upon another, slowly gaining momentum. PAKSBAB has been committedly pushing this great heavy flywheel for over 5 years now, since shortly after the devastating Kashmir Earthquake in Pakistan.
We have accomplished much during this time, each step a significant push on that flywheel, including training over 50 builders and constructing 23 straw bale houses in Pakistan as well as conducting successful shake table tests at the University of Nevada, Reno.
As a result of each push our flywheel is turning faster and faster, and I now believe that PAKSBAB is approaching the point of breakthrough, when the momentum of the heavy wheel kicks in our favor.  We just need a few more pushes.

What are we doing to get there?

  • PAKSBAB is contracting with the Imran Khan Foundation to reconstruct 100 homes in flood-affected Swat Valley, with additional villages to follow
  • We are contracting with the Rotary Club of Reading, UK to build a straw bale medical center
  • We are completing a custom owner-financed home near Jhelum, Punjab province
  • We are organizing bamboo workshops with Darrel DeBoer, architect and president of the Northern California Chapter of the American Bamboo Society
  • Surkhab Khan, PAKSBAB’s director, is wrapping up his masters in development studies at COMSATS Institute of Information Technology
  • I am competing in Santa Clara University’s Global Social Benefit Incubator, a program for social entrepreneurs to develop business acumen
  • And there is more in the works…
But to get there we also need a push from you – we need your financial support!
Please make a donation today:
  • Write a check to our fiscal sponsor Builders Without Borders (501(c)(3) registered)
  • Write a check directly to PAKSBAB (if you don’t need a tax deduction)
Please mail your check to:
P.O. Box 1083
Truckee, CA 96160
Thank you for your generosity and for helping PAKSBAB advance to the next level of our organizational development.
With much gratitude,
PS: Please share this email with others who may be interested in our work
Darcey Donovan, P.E., C.E.O.
Pakistan Straw Bale and Appropriate Building (PAKSBAB)
P.O. Box 1083
Truckee, CA 96160 USA

Pakistan Straw Bale and Appropriate Building

This is an amazing organization that I want to share with you all in hopes that you can help support what they do. You can see more about them on their website at, but to give you a general idea, they are a nonprofit organization that was created in response to the Kashmir earthquake of 2005. Much of Northern Pakistan was devastated by the earthquake and, just as we are seeing today in Haiti, Chile, and Turkey, appropriate and quality housing is the difference between life and death. To give you an idea of how important safe housing is, I recently heard that roughly 1 in 8 people in Haiti knew someone who had died as a result of the earthquake. That means that each living person in Haiti not only knows someone who died, but that someone in their family died. Counter that with the death toll in Chile where the housing is much better and more prepared for earthquakes and you’ll see that only .01 in 1 people know someone who died. That’s a shocking difference and it’s ALL because of the housing.

Please check out the video below to learn more about this amazing organization and how you can help stop needless deaths resulting from earthquakes.

Paksbab Video from ZWhit on Vimeo.

Of course, it’s more than just earthquakes. Weather, climate, and general housing quality has an affect on the people within the homes. This organization is helping to teach people how to build themselves amazing, beautiful, and efficient homes. This is a good thing!

Baling in Wet Weather

I don’t know what the weather is like where you are while you read this, but it’s pretty rainy here today! It’s always a concern for bale builders that the rains will come at just the wrong time. In fact, I’ve said it before that as soon as your bales arrive on site, you can expect rain, even if you live in the Sahara! It’s Murphy’s Law I guess. Anyway, I’ve got some simple and cool tips for you to implement when building your house and the storm clouds start to roll in.

Tarps. Yup, that’s the most obvious tip of all. The key is, how do you use them effectively.

1. Most people want to wrap their bales up tight with tarps so that there’s no way for water to get in. I prefer to wrap my bales with a top tarp that is pulled away from the bales with ropes at the bottom. This keeps the water off but allows wind to blow through and keep the bales dry from condensation.

2. Be sure to stack your bales in a pyramid of sorts so that there are no flat spots on the top of the stack. Those flat spots will collect water in the tarps which will eventually fail and the water will enter your stack. By keeping the pyramid shape, the water will always flow off and away from the stack.

3. Build a breezeway. I use tarps from the main stack attached to the house as a breezeway for transporting bales into the home. Be sure to angle the tarp so that it drains, usually to the side is best for simplicity. This keeps the bales dry from the well covered stack to their placement in the house.

4. If you can’t shape and cut the bales inside, use 10’x10′ portable tents with optional walls. This gives you a dry workspace in which to manage the bales.

5. Hang tarps from the house eaves to protect the bales as you install them. If the rain is unusual for the time of year in which you’re building, you don’t have to worry much about the sides of the bales getting wet once they’re stacked in the wall; however, keep the tops of the bales dry the entire time. If it is indeed the rainy season, keep the bale sides dry as well. You’ll be spraying them with water right before you plaster, I know, but if they get really saturated, you can end up with some rot before the dry season comes around again. It won’t likely be much rot, but none is better than any.

AAA Rating for Straw Bale Walls in Earthquakes

Here’s a great article about the effectiveness of straw bale walls in earthquakes. This study shows how strong they really are by subjecting the 14’x14′ straw bale house to 200 percent more shaking than was seen in the Northridge, CA earthquake of 1994 which holds the largest measured ground acceleration in the world. You can view the article here: or read it below.

Straw Bale House Survives Violent Shaking At Earthquake Lab

ScienceDaily (Apr. 5, 2009)  It huffed and puffed, but the 82-ton-force, earthquake-simulation shake table could not knock down the straw house designed and built by University of Nevada, Reno alumna and civil engineer Darcey Donovan.

The full-scale, 14-by-14-foot straw house, complete with gravel foundation and clay plaster walls, the way she builds them in Pakistan, was subjected to 200 percent more acceleration/shaking than was recorded at the 1994 Northridge, Calif. earthquake, the largest measured ground acceleration in the world. After a series of seven increasingly forceful tests, in the final powerful test the house shook and swayed violently, cracked at the seams and sent out a small cloud of dust and straw … and remained standing.

Donovan oversaw the successful series of seismic tests run March 27 at the University’s world-renowned Large-Scale Structures Laboratory. She was testing her innovative design for straw bale houses she has been building since 2006 throughout the northwest frontier provinces of Pakistan, in the foothills of the Himalayas between Pakistani tribal areas and Kashmir. Her design uses bales as structural and load-bearing components rather than just insulation as in other straw-bale designs.

“We’re very pleased with the results,” said Donovan, founder/CEO of the non-profit Pakistan Straw Bale and Appropriate Building (PAKSBAB) organization. “The house performed exceptionally well and survived 0.82g (0.82 times the acceleration of gravity) and twice the acceleration of the Northridge quake. The Geological Survey of Pakistan estimates the 2005 Kashmir earthquake to have had peak ground accelerations in the range of 0.3 to 0.6g.

Most people were killed and injured in that October 2005 earthquake as they slept when their poorly built houses collapsed on top of them. The magnitude 7.6 earthquake killed 100,000 people and left 3.3 million homeless or living in tents.

“Our goal is to get the largest number of poor people into earthquake-safe homes. We want to make it as affordable as possible so they build a safe home. We want to save lives.”

“Straw bale houses are used around the world, but those have posts and beams for support and rely on energy-intensive materials, skilled labor and complex machinery, making it unaffordable for the poor,” Donovan said. “In our design, the straw bales are the support, and not just for insulation. Our design is half the cost of conventional earthquake-safe construction in Pakistan. The materials we use  clay soil, straw and gravel are readily available; and we utilize unskilled labor in the construction.

“We build a small, steel compression box, pack it with straw, which is readily available from the Punjab District, literally stomp on it to compress it, add a little more, stomp on it a little more, and then finally use standard farm-type hand jacks to do the final compressing of the bales,” Donovan said.

The site-fabricated bales are not as wide as those used in a typical straw bale building, and the fishing-net reinforcement and gravel-bag foundation are nonconventional.

“We fill old vegetable sacks with gravel, like sandbags, for the foundation. The bags are fully encased, or boxed, in a mortar made from clay soil and cement. It’s as low-tech as possible using indigenous, affordable materials,” she said. The earthquake-safe buildings are 80 percent more energy efficient than modern conventional buildings at 50 percent of the cost. Her group also trains local residents how to build the homes.

“Our system is different than anything ever tested,” she said. “We’re doing seismic research on the house to have data to show its structural integrity.” While there are no building codes in the region, Donovan and the organization she founded, PAKSBAB, are pursuing an endorsement from Pakistan’s newly formed Earthquake Reconstruction and Rehabilitation Authority.

Scientists will analyze the seismic-testing results, and Donovan will write a detailed report and seismic design and construction recommendations to be published in the Earthquake Engineering Research Institute’s World Housing Encyclopedia.

Donovan has been a practicing engineer since 1986. She has a bachelor of science degree in mechanical engineering from Stanford University, a master of science in civil engineering from the University of Nevada, Reno, and is a licensed Professional Civil Engineer.

The research was conducted at the Network for Earthquake Engineering Simulation Consortium, Inc. (NEES) shake-table site at the University of Nevada, Reno as a NEES Management, Operations and Maintenance award shared-use project.

“I am extremely grateful to EERI, NEES and UNR for their generous support, and to all the hardworking volunteers who dedicated countless hours to this project, Donovan said.

The non-profit PAKSBAB relies on donations and grants to continue its work. For more project information, visit
Adapted from materials provided by University of Nevada, Reno, via EurekAlert!, a service of AAAS.

Protecting Your Straw Bale Home from Weather

The biggest concern with building a straw bale house is protecting it from the elements. Water damage is the worst enemy of bale construction and as such, is protected against with the up most attention. There are several ways to deal with water issues in a straw bale home. Rain splash, direct rain contact, humidity, leaky wall openings, and water line breaks are all potential sources of water damage. Each can be handled, to an extent, with proper planning and construction.

Let’s start with the obvious: rain. This is perhaps the easiest form of water to deal with in a straw bale home. Large overhangs, preferably 2′ or more, will direct the majority of the rain away from the walls by protecting them from direct contact. With the application of gutters on the eaves, you can virtually eliminate rain from contacting the walls. The gutters also give you the opportunity to collect your rain water for future use. If you have a multiple story building, be sure to add roof lines at each story. Intermediate roof lines serve the same purpose of directing rain away from the walls. Without them, the roof on the second story will not provide enough protection for the first story. Areas with high wind driven rain or horizontal rain, are a different situation and are harder to build straw bale homes in.

Pipe leaks are another common place of water damage in straw bale homes. These are also easy to deal with. KEEP ALL PLUMBING OUT OF THE BALE WALLS. Sorry to yell, but that needs to heard. I keep all of my plumbing to interior walls where possible. If that is not possible, I build what I call water isolation walls, like in the example above. By stopping the bales before we encounter plumbing, we are able to isolate it entirely from the bale walls. The area where plumbing has to be on an outside wall, like a kitchen sink, can then be insulated with extra insulation and the wall framed out to meet the same plane as the face of the bales. This eliminates any risk of the water leaking directly into the bales. The 3 1/2″ toe ups also eliminate the risk of the bales soaking up the water off of the floor from a broken water line.

Although I look a little crazy in this shot, I am just fine. (Thanks for your concern though) I am pointing out the tiny corner detail in the first piece of counter flashing. Notice that the piece that is cut is not cut all the way to the corner. It has a little extra flap that is folded into the window on top of the sill. This piece, when covered by the next level of counterflashing, creates a total seal in the corner. A small bead of silicone caulk can be a friend here as well. Check out the next shot:

The sill and legs of the window frame have been completely counterflashed and THEN the window is installed. Once the window is set, then it is time to go back and flash the window in its entirety, including the head which is left out of the counterflashing. This extra step is worth the effort. Windows are notorious for leaks and are certainly a place you want to spend some extra time protecting.

Now the hard one: humidity. The reality is that humidity cannot be stopped. It can be drawn out of the air with dehumidifiers, but it cannot be eliminated. If you live in a high humidity area, straw bale construction is probably not a good idea. If you live in a climate where the humidity gives way to hot and dry days, for an extended period of time, that may be enough for the bales to dry out. The deal is that humidity pervades everything and so cannot be adequately controlled. If the bales reach a moisture content by volume of over 20% then they will sustain mold growth and will rot. Exactly how the relative humidity rating of the air translates into moisture content by volume per bale is not clearly defined, at least not to me. If you consider your climate tropical, I would say no to straw bale construction. If you are right on the edge and unsure, I suggest you build a small structure first and install moisture meters to monitor the moisture content. After a year or so, you will have sufficient data to make a more informed decision.

House Wrap

House wrap often creates more damage than it prevents in straw bale houses. Why then are they required in straw bale building codes? The answer is not complicated; however, the impact of house wrap on homes of all types is.

For straw bale homes, the push has always been to provide the bale walls with a vapor permeable finish to allow any water vapor to escape the building. In most cases, this translates into an earth based plaster like clay or lime. These plasters have the ability to release vapor and thus allow the bales to dry out when the weather permits. Other plasters that are synthetic or cement based have limited ability to transfer the moisture away from the bales. In some cases, again depending on the weather or climate, the bales end up soaking up moisture from the environment which can cause decay in the walls.

So if it is true that the bales need to breathe and that the plaster that is applied over the surface can influence the vapor transfer away from the bales, why would anyone use a house wrap at all? So here is the simple answer: because that is what people do on conventional homes. Because much of the code language for straw bale buildings is based on codes for conventional construction, some things just never get tested before they become requirements. I have built many straw bale homes and many conventional homes. In both cases, I find items within the code that really do not make sense for the individual situation; however, the code is not designed to address individual situations but rather large, blanket situations. As a result, I have had to fight for what I believe and then provide some type of proof or performance guarantee from an engineer. Although expensive, an engineer’s stamp is cheaper than a failed wall system.

bales-and-vapor-barriers.JPGI do not use house wrap on my bale walls unless I really have to. In some cases, where the bales may be exposed to rain splash or snow drifts, I may utilize the material. In dry climates, I do not use the material at all because I believe the ability for the building to release moisture is more important than the attempt to keep it out. The picture above shows an example of a house wrap in the form of roofing felt applied to the bottom courses of bales. In this case, the home inspector required it on the exposed portion of a wall where wind driven rain rain was a concern. I was sure to NOT wrap the felt under the bales. This allows any moisture to drain free of the bales into the gravel at the base of the wall. Do not confuse the need for a house wrap material with the need for roofing felt over wood exposed to plaster. They are very different and the plaster protection is definitely needed to avoid cracks in the finish. The stripes on the wall of roofing felt are wood members covered before plastering.

I have learned over the years that moisture WILL get in to your house one way or another. Believing otherwise is like believing I can stop it from raining when I want a sunny day. In light of that, it makes more sense to build so that moisture can escape once it gets in. This is a simple answer to a complicated question. Indeed, there are many people and companies out there that spend countless hours and currency researching the impact of house wrap on construction projects and the results of those studies point to the inclusion of vapor barriers in conventional construction practices. Because there is limited information about the impact of those barriers on bale homes, we, as builders, are left to use our common sense and what information we can find. One thing we know for sure is that moisture can cause irreparable damage to a straw bale house. Knowing this, it is imperative that you do whatever you can to protect your walls from water AND moisture vapor build up. Exactly how you do that will depend largely on your climate, your construction materials, your mechanical systems, and your design.

Rebuilding the Town of Greensburg

Last summer, an F-5 tornado ripped through the City of Greensburg, Kansas and destroyed much of the City. Officials there have made a commitment to rebuild their city using green technologies. As it stands now, they plan to use conventional construction methods and simply add green features. I would like to see something bigger. I would like to see the City embrace a whole new style of construction for their rebuild: straw bale construction.

Can you imagine how cool it would be to have an entire City’s residential and commercial structures built with this amazing technology? Think of how efficient the City would be and what a role model for change they could be. I often hear the question: “Why isn’t straw bale construction more in the mainstream?” Usually it is because people don’t know enough about it. A project like this could change all of that.

My hope is to see this idea grow and grow quickly. If you have any ideas about how to make this a reality, please share them here. I am available to teach a workshop in the area to officials and local contractors, but need some “inside help!” I have a couple contact names and numbers I plan to check out next week. In the meantime, if you think this could work and you want to be part of something big, please chime in!

Straw Bale Houses and High Wind

I have been asked many times in the past and once again recently how straw bale houses perform in high wind environments. The answer: extremely well. I can go on about this in written form, but I honestly don’t have time today as I am busy finalizing a house in town and also have recently started a new framing project I need to get a handle on. So, without further delay….Check out the following video for a more complete response to this question.

Snow Drifts and Straw Bale Constuction

When people consider building with straw bales, they most often find their top concern is how to protect the bales from rain. All too often, snow is not considered a threat to the structure. In most cases, this is true; however, in areas where large snow drifts are the norm, the impact of snow cannot be overlooked without consequence. It is typical that climates with a lot of snow, especially powdery snow, will eventually blow hard enough to create drifts. Those drifts will pile up on whatever interrupts their path, even if it happens to be your front door!

If you expect to have snow drifts as a common occurrence on your property, you can do several things to protect your straw bale house. The first is the most simple: plant buffers. Snow drifts are created by prevailing winds working hard to move snow around. As I said earlier, the snow will pile up against anything that interrupts its path. In order to avoid piling snow against your house, give it something else to pile up on. By planting low and think shrubs around the home, you can not only improve the look of the property but also protect your house from drifting snow. A second line of defense can be planted further from the house in the form of trees. They serve the same purpose as the shrubs, but interrupt the wind further from the home which will help the shrubs handle whatever wind and snow does make it through to them. The trees can be planted such that they help with heating and cooling costs as well via solar gain and shading as well as the disruption of the winter winds.
A more drastic approach is to build the bales up on a framed platform. Instead of placing the bales on 4x toe ups, build a double pony wall: one pony wall at the exterior toe up location and another one at the interior toe ups. The height of this wall depends on the expected height of the snow drifts. Use standard construction techniques to build these walls and sheath them with plywood for lateral stability. By covering the exterior pony walls in house wrap, you protect them from the affects of standing snow. One advantage of building this way is that the installation of plumbing and electrical is made considerably more simple. The wires and pipes can be run through the open space beneath bales and then that space can be heavily insulated. The extra cost for lumber and labor to build the pony walls can therefore be recouped by the labor savings for the plumbing and electrical installations. Check out the ease of running lines in the picture below. All this while protecting the bales from snow drifts that might otherwise melt against the wall and cause moisture problems in the bales.