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Building an Energy Efficient Straw Bale Home: Design criteria for Inglewood straw bale

By Bales, Design, Issue 70, Straw Bale Construction No Comments

This article first appeared in The Owner Builder 196 August/September 2016.  www.theownerbuilder.com.au

By Brian Hodge

As we embark on our 20th owner-built home, I reflect back over the progress since purchasing property last year.

We were surprised the property didn’t have power, sewer, or water but discovered it actually had sewer connection just over the back fence. We were somewhat pleased when we received the quote for electricity connection of $5,050. Mind you, that did not include the connection of the power to our meter box.

Having mentioned the meter box, I am flooded with the memory of its incorrect positioning in my unavoidable absence and the challenges that we were faced with as a consequence (see TOB 195 June/July 2016). But who can complain. The end result was that we have revisited the design and now have a better one that is more interesting.  And who can forget the bonus sewer connection at the back of the block, which will save us around $10,000 that we would have spent for a septic system.

A place to run courses

When we first went looking for land our primary motivation was to get a low cost piece of land on which we could run the practical part of our owner-builder straw bale building workshops. This was a precursor to being willing to sell the straw bale house in Ladys Pass. To be a straw bale building consultant with nowhere to do courses and nothing to show people was not an option and the solution had to make financial sense.

Consequently, I did an internet search for ‘land under $50,000 Victoria.’ The result was land in Loch Sport, which was too small and, from previous experience, has too many mosquitoes, and land in Inglewood, Victoria. Inglewood is in central Victoria about 35 minutes north of Bendigo with a population of a bit over 1,000. It was established in 1859 and is still a great place to find gold. It has a good supermarket, hospital, permanent doctor, pharmacy and most important, a couple of good old fashioned pubs for great meals. It is also the town where my youngest son, his wife and two of my grandchildren are located. However, the criteria were primarily price and size.

There was an 8000m2 block for around $45,000 near a light industrial area, a 2000m2 for $70,000 or a 1000m2 for $35,000. We put in an offer of $33,000 on the last block, which was accepted.

Position, position…

The only issue, which was a big one, was its orientation. It is only 20 metres wide and faces north-west. In order to control heat input and get some passive solar benefit in the design, we had to design a house that is twisted on the property. This option consumes a lot of land, which was complicated by our need for wide eaves for a straw bale house. Regulations stipulate that living area windows must have a minimum of 1000mm of clear sky from the boundary, which meant that we had to be set in from the side boundary a minimum of 1900mm to allow for the 900mm eaves. We also needed truck access to the backyard to take deliveries of bales etc. for workshops, further restricting our build space.

We finally settled on the concept of building a U shaped house with a central courtyard as this would enable us to get passive solar benefit in the master bedroom and living area. Not a huge amount, but enough to make a difference. It also provided us with a outdoor private area, which is important to us as we have lived on country properties for the past 12 years.

U-shaped floor plan

U-shaped floor plan

Energy rating

I had our energy assessors check to see what difference this adjusted orientation would make on stage one of the construction, as opposed to building parallel to the front boundary. We were surprised that the energy rating actually went up from 5.4 stars to 6.3 stars even though there is only one window that faces north.

As we are building in central Victoria, the energy rating is primarily directed toward the energy required for winter heating. However, we get some really nasty weather in summer with temperatures reaching high 30s and even mid 40s. Consequently the design criteria also included resistance to summer heat. The central courtyard faces due west, however it has a deep verandah to protect smallish windows from the afternoon heat from the west, and the windows facing east are limited.

One of the big concerns for restricting heat input in summer is to avoid doors that open directly into the house from the north, as it is the north wind that brings high temperatures to the area. I have therefore included a good size entry on the northern end of the house with the external door facing east, which will dramatically reduce the impact of those hot northerly winds.

Airflow manipulation

The cooler summer breezes often come from the south-east, so we have included casement windows on the south-eastern boundary to funnel those cool breezes through the house. The benefit of correctly hinged casement windows is that they tend to trap the breeze and funnel it into the house rather than simply working with straight airflow. When you are trying to get cool air into your home it is best to open the windward windows fully but close the windows on the opposite side of the house to 50%, as this creates a vacuum resulting in greater airflow.

As this is a residential block I expect that airflow will be a bit of a challenge as we have boundary fences which will restrict it. I have also incorporated a flat ceiling in part of the house in order to accommodate ducting for an air circulation pump to force the early morning cool air through the house if the temperature in the house is higher than the temperature outside. Our previous straw bale house in Ladys Pass had the same issue, which was overcome using an evaporative cooler as an air circulation pump. The cooling function of the unit was hardly ever used, and would not have been missed, so I am planning on simply fitting an air pump this time.

The master bedroom window faces north onto the central courtyard, however the window is not within the shadow of the verandah roof so we will get good passive solar benefit in winter. It also means that we have a private outlook, and with Molly, our big guard dog, we are assured of security! (Molly is a miniature Maltese Shiatsu)

As this is house number 20 for us personally, it was difficult to find something a bit different to do, so we eventually settled on a curved roof with a curved ceiling. This will be achieved by building box trusses on site. It is a very cost effective method of roof construction and I am looking forward to trying it out, as I have never done it before.

With all the design, engineering and building permit issues behind us it is now time to get to work and build it. I am going to take my time and enjoy the process as I suspect this will be the last home that I build, although many people scoff at this idea, thinking that I am either crazy for building so many or that I am addicted to the process. Personally I am not sure, but I am going to enjoy this project as if it is my last.

Brian Hodge is the director of Anvill Straw Bale Building Consultants. He has nearly 40 years experience in the building trade, and now consults predominantly on straw bale construction. Brian is the author of ‘Building your straw bale home’ and will be blogging about his build. Anvill Straw Bale Building Consultants: Whether you are building a mansion or to a strict budget, we are here to help.  www.straw-bale-houses.com

Framing Bale Walls: How to

By Bales, Issue 63, Straw Bale Construction, Technical, Walls One Comment

By Andrew Morrison of strawbale.com

Image 1There are many different approaches to framing a straw bale house; however, there is one in particular that I have used on the vast majority of my projects over the years. It is a post and beam frame system with roots in conventional framing techniques. Because I came to straw bale construction many years ago as a general contractor practicing conventional construction, I brought some of that detailing over. I should preface this article by saying that there are right ways of framing and wrong ways of framing. The system I describe in this article lands in the “right way” column, but so do many other styles. As long as you are working with a structurally sound and safe system that brings you the best results possible for your style of building, then go for it.

Image 2One of the first details that often surprises people is the spacing of the posts in the system I use. I hear people talk about wanting to reduce the amount of notching in the bales by spreading their posts out as far as possible. I disagree with this approach and instead keep my posts relatively close together: no more than 6’ apart. One reason for this is that when the bales are stacked in between posts that are set far apart, there is no point of attachment for the bales other than the top and bottom of the wall. As such, the wall becomes weak as it is stacked higher. When posts are set closer together, the notches at each location provide a point of connection to the frame and make the wall much stronger both during construction and for the life of the structure.

Image 3One way I keep the posts close together is by incorporating them into the window and door frames. By using 4×4 posts as the king studs I end up with wider nailing surfaces on either side of the opening. This allows me to attach the finish trim, plaster channel and/or plaster lath, and welded wire mesh around every opening with positive attachment to the frame. These king studs serve two purposes by providing the nailing surface and by acting as part of the overall structural frame. Because windows and doors are placed in many locations around the home, and because I otherwise limit my post spacing to no more than 6’, I can minimize the wall beam size as a result. This minimal wall beam is important because the bigger the beam, the more expensive it will be. Further, larger beams are made from larger trees (unless an engineered beam is used) and I want to reduce the size of the trees I am using in my projects for environmental reasons.

Okay, let’s take a look at how the system works and why it can save time and money in your building process. I’ll simply lay out the process so you can see, step-by-step, how it comes together.

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THE SITUPS*: Super Insulated Tilt-Up Panel System.

By Bales, Issue 63, Prefabricated Panels, Straw Bale Construction, Uncategorized, Walls One Comment

By Huff ‘n’ Puff Constructions

Editors Note: We plan to have a comprehensive article covering as many of the tilt-up straw panel systems on the global market as we can in Issue #64 due out in July.  Please also note that the images associated with the thumbnails on this page are of large size.  We wanted to keep them original size to allow you to see details clearly.

INTRODUCTION
Recent times have brought an increasing wave of environmental and energy efficiency awareness in the building industry throughout Australia.  This increased awareness of the effect of logging on our forests, lakes, and streams, as well as heightened concern for the energy cost and efficiency of our buildings and ever-increasing costs of construction materials is bringing tremendous pressure for change to the Australian building industry.

A primary focus of this change is the development of alternative forms of construction for single and multi-family housing as well as commercial and industrial buildings.  With a tradition that dates back almost 200 years, the Australian building industry has utilized timber extensively for use in wood frame construction, concentration on wood framing timber as the principal raw material for the structural shell of the majority of our housing and much of our light commercial structures has tremendously diminished our hard wood and softwood forest resources in Australia.

The cost of framing timber has more than doubled in the past five years. The price of timber is projected to continue to rise over the course of the next decade with additional concerns over the quality and availability of that timber.  The price and in some areas the availability of energy has added a new and important factor in most building projects.  With these facts in mind, the building industry, known for its rigidity and resistance to change, will have to look at replacement materials for framing timber in home and commercial construction.

THE SITUPS*
We are in the process of developing and bringing to the market place a unique, and ecologically sound, structural insulated panel building system.  These panels will be able to be put into place by two people.  This structural panel system provides a cost-effective, building system that is based on an environmentally responsible manufacturing process.

Huff ‘n’ Puff Constructions are manufacturing a structural super insulated panel that uses as its core material waste agricultural cereal straw from wheat and other cereals commonly grown in Australia.

SITUP Prototype

SITUP Prototype From TLS #24

With the recent high rise in energy costs and energy availability this product’s value to the builder and his client is a product that is more important now than ever before.  THE SITUPS* is highly competitive to conventional building methods.  With the reduced construction time, energy savings, non-toxic nature of the product, and strength and durability of the product indicate we have a building system whose time has come.

HISTORY
It was on the banks of the Murrumbidgee River at Hay that we made our first SITUP.  This event was first published in The Last Straw many moons ago now.  It involved a BIG chain saw and a jumbo straw bale 2.4 m x 1.2 m x 1.2 m (8’x4’x4’).  We made three panels out of the one bale and had a lot of waste with the “method” we used at that time.  Back to the drawing board…  [Huff ‘n’ Puff shared this technique in TLS #24, Winter of 1998]

01 Testing 2

Testing

In between building straw bale houses and wineries we kept on refining the process over the past 8 years.  Eventually we got an order to make 60 x 2.4 x 1.2 x 150 mm panels for a straw bale house that we were building in Kangaroo Valley, near Sydney.  These panels were to be used for the internal walls and are non-load bearing. 

We had these internal panels tested at the University of Western Sydney.  Our tests were to establish their load bearing and wind loading capacity.  They did not pass muster for load bearing but showed us their potential.  However the size of 150 mm wide proved to be very hard to manufacture and will need a lot of refining in the 03 Kangaroo Valley 1 (1)process to make them a worthwhile proposition.

FIRST LOAD BEARING PROTOYPES
After many experiments and research we have chosen a method that we feel has the potential to change the way we build with straw bales now and into the future.  We also realise that several straw panel systems are now on the market in parts of Europe and Canada.  Our opinion is that more is good and will only lead to the acceptance of building a house, flats and even high rise units and many other types of building by adopting straw as the medium in tilt-up wall technology.

07 Wagga Wagga 2 (3)

Near Wagga Wagga

We have now completed two SITUP buildings in New South Wales.  One close to home in a suburb of Wagga Wagga, and the other on a farm near Yass, which is close to Canberra.  We are now filling an order for a three-pavilion SITUPS home in the Hunter Valley of New South Wales.

11 Yass 1 (4)

Near Yass

The SITUPS are currently 2.450 to 3.000 metres high and come in various widths from 600 mm to 1.2 metres.  We can also make them between 350 mm and 450 mm wide.  The cladding can be a variety of material from renders to weatherboard, corrugated iron and many other forms of external sheeting.  Internally they can also be clad in render or Gyprock and various types of lining boards.

We are also developing a portable SITUPS factory to make these on a building site.

SUMMARY
The SITUPS will greatly reduce carbon emissions from new buildings through savings during manufacture and the operation of the building.  We already know this, having built many straw bale buildings since 1998 and together with 145 straw bale building workshops now completed.

Hunter Valley

Hunter Valley

Our goal is twofold; first, to reduce the carbon impact of modern buildings with the SITUPS and; second, to be able to utilize a waste product of our wheat and rice cereal growing in Australia where rice straw alone is burnt at an alarming rate.  Some one million tonnes goes up in smoke (particulates and carbon) every year.  Enough straw to build, say, 44,000 three-bedroom SITUPS homes on an annual basis and that is only from the rice grown in one area of Australia.

All the other benefits that come with straw bale homes that we have know of and practiced over the past 17 years apply equally to the SITUPS.  The main difference to conventional building with straw bales is that the SITUPS are uniform pre-compressed at time of manufacture and hence are very fast to build with, saving time and money.

* The SITUPS is a registered trademark of Huff ‘n’ Puff Constructions

John Glassford and Susan Wingate-Pearse, The Straw Wolf and My Little Wolverine
Huff ‘n’ Puff Constructions
“Jack’s Flat”
22-24 Moore Street
GANMAIN N.S.W. 2702.
AUSTRALIA
61 2 6927 6027 Work
0412 11 61 57 Mobile
[email protected]
http://www.glassford.com.au

Community Rebuilds – Path to Zero Waste

By Bales, Community, Issue 63 One Comment

By Stuart Jeffrey Hart

SJH_3556

Courtesy of Stuart Jeffrey Hart

Community Rebuilds is a nonprofit organization that builds straw bale homes for low-income families in Moab, Utah.  The homes are built by volunteers who exchange their time for an education in natural building and sustainability. Our student intern volunteers commit to the entire 4 month build, participating in the foundation pour all the way to ‘key in the door.’ Our program is committed to replacing dilapidated, energy wasteful trailers, for highly efficient homes that use a fraction of the energy to heat and cool.

Community Rebuilds was been awarded this year’s “Innovative Path to Zero Waste Award” by the Utah Recycling Alliance. Here is how we achieved it.

To reduce the waste we produce on the build site, we follow the ‘Reduce, Re-use, Recycle’ principle.

Reduce – Our design choices help us reduce the amount of building materials that we use. When ordering roofing metal for example, we use Google Sketch-up, a computer-modeling program, to lay out the exact cuts needed. It shows us where the off-cut from one piece can be used elsewhere. This allows us to order the precise lengths of metal needed, meaning less materials are ordered and we produce the minimum waste possible. All lumber is ordered at lengths specific to the building needs. We order lumber lengths as close to the actual length needed to reduce the amount of material left. The conventional approach is to order only 16 ft lengths, then cut everything from those. The remaining pieces are often too short to be used and are discarded as waste.

Pallet Warriors (courtesy of Douglas Nichols)

Pallet Warriors
Courtesy of Douglas Nichols

A major design choice is for our houses to incorporate natural materials that are compostable. We choose to build the walls of our homes with straw bales, an agricultural industry waste product that would otherwise be burned. Extra bales and waste straw are composted. The homes we build have earthen floors and the walls and ceilings are plastered with earthen plaster. We use a combination of locally sourced sand, clay and straw for all of these applications. Plaster mix that is dropped during plastering or left over at the end is either re-hydrated and used again, or simply spread in the garden to become the soil.

Reuse – We incorporate used and repurposed building materials into our homes to reduce the cost of the homes and to reduce the amount of new building materials required. We construct non-load bearing interior walls with pallet wood salvaged from the local waste stream and earthen plasters. In addition, we reuse functional lumber, tiles, doors, windows, interior lighting and plumbing fixtures, sinks and toilets.

During construction we reuse our waste as much as possible and we try to incorporate other people’s waste material when possible. When sheeting the internal walls of our homes, we use drywall off-cuts from other build sites. Conventional construction crews will not use drywall scraps. Scraps will usually be the end of a 12′ x 4′ drywall sheet. We flip all the 4′ pieces horizontally and use them to span our 2′ on-centre framing.  In our homes we piece together a total of 960 sq ft of ‘waste’ drywall. We mesh tape the extra seams and clay slip the gaps, and then our earthen plaster hides all.  By collecting the salvageable scraps and using them in our homes we reduce the amount of waste destined for the landfill and save purchasing new materials.

When we are building with other conventional materials excess material and remnants are incorporated in the home as much possible. We use rigid foam insulation sheets to insulate our foundation and underneath the floor. Scrap from this process is saved and inserted into the roof cavity before we blow in cellulose. Some burnable wood scraps are collected together and used by the volunteers in their wood burning cob oven and communal fire pit. The rest is donated to a local family who use it to heat their house throughout the winter. We donated four cubic yards of burnable wood scraps from our most recent build.

We choose to use as little wood that contains glues as possible. This means that more of the wood scraps are burnable. It also reduces the amount of potentially harmful chemicals in our homes. To replace OSB sheeting on the roof, we use rough sawn 1×10 wood for the same price. We have replaced LVL beams with rough sawn 4×12’s.  Both of these come from the Colorado Rockies where pine beetles have devastated huge areas of pine trees leaving them standing dead.

Reused MaterialsRecycle- We challenge ourselves to limiting our waste production to one domestic garbage bin (0.5 cubic yards) weekly. Our waste consists mainly of non-recyclable packaging and cumulates to an average of 8 cubic yards per build.  By comparison, we estimate that local private contractors will dump approximately 30 cubic yards of waste during a similar sized build. 
To accomplish our low waste goals, we begin each new home build by creating pallet-recycling bins on our construction sites. Metal, plastic, cardboard and wood scraps are stored in them. When we need a small piece of lathe to patch a crack, some wood for blocking or cardboard to protect our floor a quick check of the recycling bins can save cutting a new piece. Once the build is over anything that hasn’t been used is recycled. At the end of our previous build we recycled one cubic yard of scrap metal and one cubic yard of cardboard.

Our goal is to create a quality affordable product with minimal waste and environmental impact. In doing so, we educate the next generation of builders how to move towards zero waste. Our students learn how the current building methods are wasteful and inefficient and how, using just a small amount of planning, we can change the home construction paradigm for the better. We are building homes in a smarter, more sustainable way. Our homes’ energy performance, thoughtful construction methods and quality stand as an example for our volunteers, the community and the construction industry as a whole.

Jeffrey was an apprentice and natural building instructor with Community Rebuilds from 2012 – 2013. 
He is now heading home to his native England to build small, affordable, straw bale homes using the Community Rebuilds volunteer/educate model.  He can be found at www.jeffreythenaturalbuilder.com.

 

Healthy Living, Healthy Building (Building an EcoNest)

By Bales, Design, Issue 62, Straw-Clay, Walls No Comments

By Elaine Brett

Finished WallsTwelve years ago I had never even heard of building with straw.  I lived in a four-bedroom colonial house in a subdivision in Maryland.  The conventional American Dream – good job, big house, nice cars, the monthly lawn service, the health club membership, 24/7 access to shopping …

Then on my 49th birthday came the American nightmare.  A wake up call from Mother Nature.  Sometimes she needs to smack you hard to get her attention.  My wake up was a cancer diagnosis that sent me spinning into a quest of asking questions and trying to understand “how could this happen to me?”

One path of my quest (probably driven by my background as a chemist) sent me questioning the chemicals in my environment: the food I was eating, the air I was breathing, the water I was drinking, the lifestyle I was living, the buildings in which I was residing and working.  The answers took me beyond the overt pollution of urban air and water to the hidden nooks of micro pollutants in synthetic materials, chemical food processes and endocrine disrupters in simple everyday products.

The quest also took me on another path.  I began looking for a place to live clean and chemical free, or at least as clean as is possible.  And that’s how I came to a small town in the North Fork Valley (www.northforkvalley.net) in Western Colorado.

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Straw House Patent (Feuillette House Follow-Up)

By Bales, Community, Design, Issue 62, Straw Bale Construction, Technical, Walls No Comments

As an update to this post about the Feuillette House in France, here is a patent in the United States for straw bale construction.  It was filed on June 6, 1921 and is a very interesting read for the bale construction history buffs out there. The author was Emile Feuillette himself and approved on June 6, 1921.

This is not the oldest patent on bale construction as we documented back in Issue #21 in the Winter of 1998.  That title goes to Josiah M. Leeds (of Indiana, not Nebraska) in 1880.  The article describes and contains illustrations of three subsequent straw bale building patents (1885, 1903, and 1905).  Issue 21 can be ordered on our CD of the first 40 Issues here.

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Red de Construcción con Paja

By Bales, Community, Issue 62, Straw Bale Construction No Comments

logoRCPBIENVENIDOS, we’re the Spanish-speaking straw bale network RCP (Red de Construcción con Paja), or Network of Building with Straw.

The RCP network of straw bale construction is a non profit organization with about 75 active members, but with a lot of fans. Our webpage has more than 7,000 visits a month.

RCP is now 8 years old, as it was born 2005 in Barcelona, Spain. Only couple years later our little magazine, in 2007, “BRIZNA” was printed for the first time where we document our straw bale building experiences twice a year.

The aim of RCP is to be open and to support other Spanish speaking countries to spread the word, especially if they do not have their own network. That’s why we don’t call ourselves the Spanish Straw Bale Network.

Traditional and Contemporary Natural Building in Korea

By Bales, Design, Energy, Floors, Issue 62, Plaster, Straw Bale Construction, Straw-Clay, Walls No Comments

By Kyle Holzhueter

Editors Note – This article is a feature length pictorial look at the various aspects of natural building in Korea.  The full-length article will be in the upcoming issue of The Last Straw and is available in its entirety right here on the website for subscribers.  Make sure you have a subscription soon so you won’t miss this stunning array of natural building techniques.

Traditional Korean Architecture

Traditional Building in Korea relied primarily on natural and local materials.  Buildings were traditionally designed according to the 間 (Korean: ka, Japanese: ken) module, a common measurement found in east Asia.

East Asian Modual

East Asian Module

Traditional Korean homes generally have a timber frame with adobe or wattle and daub infill, though regional variations are found throughout the country.

Traditional House

Traditional House

Regional Variation

Regional Variation

Especially on Jeju Island where volcanic rock and strong winds are abundant, homes traditionally consisted of a double wall system with an exterior wall of volcanic rock surrounding an interior wall, creating a protected corridor around the house.  This in turn, protected the interior walls from wind and rain and improved the thermal performance of the home.  Also because of the strong winds, thatched roofs were generally secured by a net of straw ropes.

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A Strawbale Residential Building Code for the United States

By Bales, Codes and Permits, Issue 62, Straw Bale Construction, Technical One Comment

By Martin Hammer

Mark, Martin, David and  Laura with ICC sign

Mark, Martin, David and Laura with ICC sign

October 14, 2013 marked an historic day in the history of strawbale construction and natural building.  A proposed appendix on Strawbale Construction, and a separate appendix on Light Straw-Clay Construction, were approved at the International Code Council (ICC) Final Action Hearings in Atlantic City, New Jersey.  Both appendices will be included in the 2015 International Residential Code (IRC) for one- and two-family dwellings.  (See sidebar regarding the Light Straw-Clay appendix.)

This has far reaching implications, because the IRC is the basis for the Residential Building Code in virtually every jurisdiction in the United States.  In addition to making permitting easier, obtaining financing and insurance through conventional channels is expected to become much easier, because concerns about structural capacity, fire resistance, moisture issues, etc. are clearly addressed in the code

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Adsorption (More Building Science)

By Bales, Building Science, Issue 62, Straw Bale Construction, Technical No Comments

Building-ScienceBy Chris Magwood

An important concept to understand when considering moisture and building materials is adsorption. Moisture in vapor form infiltrates any and all materials. The surface of most materials will offer individual water molecules an electrically charged attraction, and the water molecules will “stick” to all available surfaces. The makeup of plaster and of straw bales offers a vast amount of surface area for this adsorption. Plasters are full of micro-pores and straw has great deal of available surface area as well as micro-pores in the hollow stems. Together, these materials allow a surprisingly large amount of moisture to safely adsorb onto/into the materials without the water molecules accumulating in sufficient layers to become drops of liquid water. Bales and plaster can hold a remarkable amount of moisture in adsorbed form. “For a 8 pcf (pounds per cubic foot) bale, more than 1 pound of water (approx. 1/12 gallon or 0.46 liters) in vapour form can safely be stored per square foot of wall area” according to John Straube in Building Science Digest BSD-112. This explains why the walls can perform so well as “vapor open” or “vapor permeable” systems.