Q. How long does it take to build a natural home?

A.  The construction of any home is highly variable and ranges anywhere from 4 months to over 2 years.  Some of the variables that affect this time frame are complexity of design, labor force, funding, and forces outside of the homeowner's or contractor’s hands like material economy and global pandemics.  In general, the more custom and unique the structure, the more time needed to complete.  

We encourage our clients to spend about a year observing, designing, and planning before construction begins as this phase is most critical for a timely and successful project.

Q. WHAT IS COB?

A. Cob is one of the oldest building techniques of human civilization.  It involves blending clay rich soils with an aggregate like sand and a fiber component like straw or even ungulate dung to make a plastic homogenous mix.  This mix can be used to form walls, mortar stones, and sculpt without the need for form work.  

Nearly every continent on earth has some form of ancient cob building tradition. Today, all over the world cob is making a comeback but faces challenges of modern seismic and energy codes.  Cob is a poor insulator but performs well as a thermal mass which helps maintain indoor temperatures.  

Q. WHAT IS Strawbale Building? - Hay vs Straw

A. Hay is for horses, straw is for houses.   Straw consists of the stalks and stems of cereal grains like wheat, rye, barely, rice, oats, and more.  Hay is the staulks, stems, blades, and seed heads of cereal grains; which are harvested and bailed with nutrition for animals in mind.  Strawbales are mechanically pressed and tied into blocks which are an easily stackable building block with incredible insulative properties.  Strawbale homes first appeared in the late 1800s shortly after the invention of the first baling machines in the midwest of North America.  Since the 1980s strawbale building has been gaining interest and attention as it has become a permissible code compliant material in many states as well as internationally.  

Q. How good is straw at insulating a house?

Strawbales have remarkably high R-value given the low level of processing required to achieve these properties. Testing shows that the R-Value of 18-24” bales is between R-26 and R-34, the California Energy Commission settled on an average of R-30, far above the required California code requirements.  

However, simply having a high insulation value does not guarantee a high performance energy saving system.  The plaster skins applied to the outside and inside of the walls help reduce the flow of heat and air and thick thermally dense plasters to the interior of the wall create a thermal battery which greatly reduces energy costs by moderating interior temperatures.  

This battery buffers the swing of outside temperatures creating a balanced indoor environment.  For example, the temperature outside may vary from 58 to over 100 degrees in a single day, that's over 40 degrees of change or swing! While, on the inside of a strawbale home the temperature may swing 4-6 degrees without any need for active systems like HVAC or other heating or cooling.  We call this a passive energy system, one which by design facilitates a desired action without the need to expend energy to create the desired result.   

Q. Will the straw decompose? What about Pests?

A. Many cereal grains have to endure wet winter and spring conditions in order to grow to maturity; to do this they produce silica in their plant tissues to resist the forces of decomposition and aid in rigidity to gain access to sunlight and project seed heads upward.  Rice straw, being submerged in water for much of its lifetime has a very high silica content and decomposes very slowly.  If left in fields and tilled into the soil many cereal grains take six months or more to breakdown.  

In a bale, protected from the elements by a roof and wall coverings, straw can easily last a century if maintenance is kept up on the structure.  Archeologists find straw in ancient tombs, buried in digging sites and in caves around the world that are thousands of years old.  In short, If kept dry, straw will not degrade.

Straw does not have seed heads, it is just the stalks and stems of cereal grains, and is tightly packed in a bale; this leaves little room or reason for pests and rodents to go exploring.  In a strawbale wall system, the bales are protected on all sides, usually with a thick and dense plaster of earth, lime, or cement; digging, boring, or chewing through this envelope is very difficult for insects or rodents.  

Q. Isn't there a huge fire danger?

A. Despite what historical memory tells us, strawbales, when installed in a building are very resistant to fire. Fire requires fuel, oxygen and high temperatures to sustain and become destructive.  A mechanically compressed strawbale however is too dense to burn, there is not enough oxygen between the fibers for the bale to do more than smoulder.  When covered with a plaster skin of earth, lime, or cement, strawbales have a fire rating of over 2 hours as determined by numerous testing agencies including; The Appropriate Technology Group at Vienna Technical Institute, The Danish Fire Technical Institute, University of California, The National Research Council of Canada, The NSW Rural Fire Service of Australia, and others.

This fire rating of 2 hours or more qualifies strawbale wall systems as commercially compliant, withstanding direct flames of over 1400 degrees Fahrenheit before cracking.  

 Q. Aren't bales susceptible to humidity and moisture?

A. If left unprotected, strawbales can absorb and release a significant amount of humidity and moisture.  When coated with a plaster skin, bale wall assemblies become vapor permeable, meaning that moisture is drawn in and out of the bales and released into the air slowly through the plaster skin. It is said that strawbale wall assemblies are breathable. This breathable action can help regulate indoor air quality.  Properly designed and installed strawbale wall systems are not very susceptible to humidity and moisture.  

The greatest danger humidity and moisture present to strawbale construction is during construction and installation.  Storage on the construction site which protects the bales from wet weather is important.  A strawbale humidity reader is used to check the bales for moisture content which should be 20% or less when installing.  When purchasing bales, the seller should be informed of your construction intentions and desired humidity level of 20% or less to ensure a timely install free from excessive moisture.  

Q. Does straw bale meet building codes?

A. Yes! The first strawbale building codes were adopted in Arizona in 1995 and finally in 2015 into the IRC (International Residential Codes).  Since the beginning, teams of hardworking men and women have been researching the building science of strawbale systems best practices.  There now exists a detailed code language called ‘Appendix C and Appendix R’ which explains the proper usage of these natural materials.  

Q. How are Strawbale walls finished?

A.  Strawbale walls are typically covered in a plaster system of earth, lime, gypsum, or cement.  However, new techniques of straw construction have allowed for straw to be protected by sheathing materials like plywood and drywall.  Many strawbale builders/clients prefer the aesthetic benefits of the plaster skin system as it allows for the highlighting of natural curves and space around windows and doors especially.  

Q.How do you incorporate plumbing and electrical?

A. There are numerous techniques for installing plumbing and electrical.  Where plumbing lines pass through strawbales there is potential for condensation or pipe sweating; often a sleeve is placed in between the bale courses or bored through to pass plumbing lines through.  Electrical can be run with standard Romex cable if circuits are run at least 3 inches into the wall to avoid punctures same as standard wood stud construction.  Running conduit or UF(which is rated for direct burial) cable is another option for areas where extra precaution is required or desired.  Electrical boxes can be attached to framing as per standard construction methods or floated into strawbales at desired locations by driving wooden stakes into cavities notched into the bales for secure holding.  

By thoughtful design, many challenges presented by plumbing, electrical, HVAC and other internal systems can be addressed and mitigated.  Trusses and internal wet walls are just a couple of easy solutions to these challenges.  

Q. Do green/natural buildings last?

A. When lived in and maintained, natural buildings can last millenia.  The crucial component of any long lasting structure is maintenance.  The concept of ‘maintenance free’ is a bit of a misnomer as it usually means, free of maintenance until it needs to be replaced. An example of this would be a coat of exterior paint; it is nearly maintenance free, until it needs a new coat which, depending on the environment, can be fairly often and is a continual upkeep cost.  Naturally built structures may require more routine maintenance, this usually consists of very low cost repairs.  Simple maintenance, like annual cleaning of gutters and downspouts, can greatly reduce the upkeep cost of any structure conventional or alternative

Q. How much does an ecological structure cost?

Generally speaking to give an idea, the cost of our structures start at $120 sq. ft. for non permitted small projects under 140 sq. ft to $300 per sq. ft. for permitted custom homes.  The estimate of $300 per square foot does not include finishes like: Light fixtures, plumbing fixtures, cabinets, counter tops, flooring, tile, windows, roofing, or finish plastering.  These phases are hard to estimate on a per square foot price because clients may choose inexpensive products or high end products.  This price per square foot only takes into consideration the enclosed building shell with labor for: leveling coat plasters, rough electrical, rough plumbing, window installation, roof framing and sheathing.   

The square foot price can go up or down depending on the finishes chosen (windows, cabinets, flooring, light fixtures, plumbing fixtures, etc.) in most cases around $325 per square foot for mid range finishes, and up to $450 or higher per square feet for high end finishes.   This price is almost exactly the same as conventional buildings, except our natural structures are one of a kind; built with love and care. They are non toxic, provide a healthier indoor environment, use natural materials, save on energy costs and of course, beautiful. 

These estimated prices do not include design, earthworks, septic, wells, PG&E hook up, or any solar power installation.  

We work with designers, engineers, contractors and the county.  Their fees are not included in the above square footage estimate and can vary.

These estimated costs are based on 2019 averages.  

Q. How can I make my project more affordable?

• This is a big question and has many avenues for affordability. Consider doing most if not all of the materials resourcing yourself.  This takes time and paying someone to do it can add up. 

• Take time to plan and design the structure that you are wanting so consultations can be kept to a minimum and design decisions can be made faster.

• Build small.  Depending on the structure, keeping the design small and simple will save a lot of time and money. 

• What materials may you have available on your site? Utilizing abundant and local resources can save money, just don’t forget the time it takes to harvest and process them.

• Workshops can also be facilitated to bring in extra hands for the bulky stages of work.  However, the energy it takes to host can be demanding and unless you plan to teach the workshop yourself, you will have to hire the instructor who is experienced with these types of workshops.  But also, the educational magic that happens at workshops is often priceless.

• Consider doing some of the work yourself.  You may feel comfortable taking on some phases on your own, you have us to learn from while we are there. 

If you have questions or concerns please don’t hesitate to reach out to us!