Straw Bale Shed

By,

Tony Frink

 

-Photo taken by Tony Frink

                                                        

 

A bale of straw, what is it good for? Until now, not a whole lot.  Every year millions of tons of straw are burned, polluting our clean air and wasting a resource that could be put to use.  Straw bale construction is a building method that is becoming more and more popular as time goes on.  Structures across the country are being constructed using bales of straw as the primary building material.  The many benefits of building with straw bales are causing people to break away from the more conventional building methods, and build with straw. 


 Construction Costs

     One of the main advantages to straw bale construction is initial building cost, insulating properties and ease of construction. Typical costs for the average straw bale structures are as follows:

  
Category Cost/Square Foot Description
Very Low $5-$20 Strictly builder labor with the use of salvaged materials
Low $20-$50 Major construction by sub contractors, remaining by owner
Moderate $50-$80 Normal structure built by contractor
High $80+ Built by contractors with many custom features

 


Insulating Properties

        Another major advantage of straw bale building over conventional methods is the excellent insulating properties of straw bales. The insulating properties of construction materials are measured with an R-value rating.  Wood has an average R-value of R-1 per inch and fiberglass bat insulation has a rating R-3 per inch. Straw bales have R-values as follows:    

Material  R-value
Wheat and rice straw baled with the grain 2.4 per inch
Wheat and rice straw baled across the grain 3.0 per inch

This means that the average three string straw bale has an R-value of 54.7! So its insulating properties are equal to a piece of wood 54.7 inches thick.

-Notice the very thick walls of the straw bale shed. This feature gives the structure excellent insulating properties.     


 Overall Costs of Constructing and Owning Straw Bale Home  

       One of the many benefits of straw bale construction is the ease of construction.  The main reason why straw bale structures can be constructed for much lower costs than conventional building methods is the fact that the majority of the labor can be easily performed by the owner.  This saves the owner the cost of hiring and paying a general contractor, as most people would have to do using conventional building methods.   When a house is built using conventional building methods contractors are almost always brought in to complete the foundation, framing, plumbing, electrical, dry wall and finish carpentry work.  When building with straw bales, the owner and a few friends can easily construct almost the entire house in a far shorter time than would be necessary for a non-straw bale type of structure.

 

 

 

 -The simplicity of general straw bale construction can be seen here.

  

CONVENTIONAL HOME

Construction cost $   82,500
Down Payment (20%) 16,500
Finance 118,800
Energy (heat and cooling)  36,000
Total life 171,300

                                  

 

STRAW BALE-PARTIALLY OWNER BUILT

Construction cost $  40,000
Down Payment 8,000
Finance 57,600
Energy  9,000
Total life-cycle cost 74,600

Savings                                                                    96,700

STRAW BALE-TOTALLY OWNER BUILT

Construction Cost $  20,625
Down payment 0
Finance 0
Energy  9,000
Total life-cycle cost 29,625

Savings                                                                   141,675

-Finance, down payment and energy costs are derived using average finance rates and energy costs over a 30 year life cycle.


Common Concerns About Straw Bale Buildings

Many people worry about the safety and durability of straw bale construction over a long period of time. While the CCAT straw bale shed has only been around for slightly over a year, many other straw bale structures across the country have stood the test of time.  Common concerns about straw bale buildings are fire safety, pest and rodent control, earth quake safety, decomposition of bales, and over all integrity of structure.  The fact is that straw bale structures, when properly constructed, do as well or better then conventional buildings in most of these categories.  Straw bales resist fire amazingly well. The bales will not quickly burn, they smolder for long periods of time where conventional wood built homes would have suffered major or total loses during this time.  The straw bales are impervious to pests and rodents if properly sealed and a quality foundation is build. The straw bale structures life span is entirely dependent upon the quality of work during the construction phases. A good solid foundation, a good strong water tight roof with large overhangs, and all walls being fully sealed from the elements, are all very important in extending the life of a straw bale structure.  The CCAT shed uses a sheet metal roof with fairly large overhangs to keep the water off of the bales of straw. If the straw stays dry it most likely will not decompose and lose its structural integrity.

 

 

 

 

Click here to see the links to other straw bale construction sites on the web.


Click here to see the references used to create this page.


Click here to see pictures of straw bale structure across the country.


Click here to return to the CCAT homepage.


 

This page was last modified on:

05/06/02