More Straw Bale Building. Peter Mack
and harder to handle. If you are preordering your bales, be sure to specify that you want them on the tight side. But what exactly is tight?
Methods for assessing tightness vary from the low tech to the scientific. For the low-tech method, pick up the bale by its strings and check that they don’t lift from the bale by more than five to six inches. The bale should also maintain its integrity if you lift it by just one string and shake it around. If it spills out when you do this, the bales are too loose. Be sure you sample a number of bales from different places in the stack.
Some attempts have been made to more scientifically quantify tightness. The Arizona and California Straw Bale Codes specify that bales shall have a minimum calculated dry density of 7.0 pounds per cubic foot. This requires you to weigh, measure, and record the moisture content of the bales. If you are in serious doubt about the bale quality, these figures may be useful to generate. But don’t forget, the farmer has likely been around bales for a long time. He or she will understand the concept of a tight bale, and their opinion can mean as much or more than your calculations.
Dryness
Starting with dry bales is of utmost importance. Like any organic material, straw will decompose if the right conditions of moisture and temperature exist, and by ensuring that the moisture content is low, you remove one of the essential factors for decomposition.
Like methods for determining tightness, methods for determining moisture content vary in complexity. For the low-tech option, open the strings on several different bales and look inside. Is the straw moist to the touch? Is it crisp? Does it smell damp? Are there any hints of black mold on the straw? Study the storage facility. Is the roof good? How about the floor and walls? Ask the farmer about the weather conditions when the straw was baled. Was it a damp summer with lots of rain? Typically, if bales pass these tests, they are fine to use.
3.3: The strings of a bale shouldn’t lift more than 5 to 6-inches when you lift the bale. The bale should keep its shape and not bend or sag.
If you are buying bales from a previous year’s harvest, the survival of the bales without rot or mold occurring can tell you that they are adequately dry.
If you want to be more scientific, use a moisture meter to get an accurate reading of moisture content. The farmer may own a meter or may be able to borrow one from a neighbor or from a co-op. Moisture meters are most often used on hay bales but can give accurate readings for straw as well. Moisture content of 20 percent is considered the safe maximum for a building bale (this is the same figure for lumber). To calculate the dry density of a bale, subtract the weight of the moisture from the overall weight of the bale.
3.4: If you can find straw that is being stored in a well roofed barn, chances are it is nice and dry. Leave it in the barn until you actually need it.
Keep in mind that farmers don’t want wet bales either. Moist bales will mold in the barn and make for lousy bedding for the livestock. It is common farming practice to bale straw under good dry conditions, and to keep it dry once it has been baled.
Size
Size is the least important concern for building bales.As long as the bales are of consistent height and width, their exact dimensions are not so important. Two-string bales, as shown in Figure 3.5, are generally 14 inches high, 30 – 40 inches long and 18 – 20 inches wide. Three-string bales are 14 – 17 inches high, 32 – 48 inches long, and 23 – 24 inches wide. It doesn’t matter if your bales vary from these numbers, as long as they are consistent with each other so that your bale wall doesn’t vary greatly in height or width.
Other Factors to Consider
Before You Buy
Some general concerns about bales should be addressed.Many modern combines chop the straw into short pieces as it is harvested. This chopped straw can be baled into good tight and dry bales, but they are much more difficult to cut, shape, and trim. The best bales contain high percentages of long, unbroken straw.
Baling machines affect bale quality, too. An improperly adjusted baler will tighten one string more than the other, producing lopsided, curved bales. If there are many such bales, avoid purchasing, since it will be difficult to bend and straighten each bale (however, if you’re building a round house, these are the bales you want!). Each bale has a cut side and a folded side. The folded side will always be shaggier than the cut side.Examine both sides to see if they are relatively smooth and even. Smooth bales will require less trimming later on and are more desirable.
3.5: Common bales come in either two- or three-string sizes, with roughly standard dimensions.
Check bales to be sure that there is not too much grain left mixed in with the straw. While some seed heads inevitably make their way into bales, large pockets of seed or a high percentage of straw with seed heads intact are grounds for declining the purchase. These seed heads attract pests and can activate microbial activity in your finished wall.
Grain crops are often treated with chemical fertilizers and sprays. While these chemicals have passed tests for use in food production, you may wish to find out which products have been used on any straw you purchase. It is possible to find straw that has been grown organically or with a minimum of chemical interference.
What Price, Fair Bale?
As an agricultural product, straw bales vary in price from season to season and from region to region. Common prices vary from Can$2 to $5 per bale.We like to offer farmers the best possible price for their bales, rather than negotiating the lowest possible price. One of the advantages of bale building is the creation of a valuable product for farmers, and we believe it is important to foster good relations with bale suppliers. The cost of your bales will be one of the lowest on your budget, even if you voluntarily offer top dollar. And offering a generous price helps guarantee that the bales will meet all your requirements.
You can also request that the farmer bale you some half-sized and smaller bales. This is a simple adjustment to make on the baling machine, and the resulting smaller bales will minimize the amount of time lost to cutting and retying bales during the wall raising.While this may cost a bit more, it will be worth every penny later on!
Transportation costs may be included in the price of the bales or may be additional. Be sure you find out. If you live close to the source, the farmer might deliver the bales at quite a reasonable cost, or you might be able to make a few trips with a truck and trailer. If not, the farmer may suggest appropriate transportation.
Commercial carriers are also an option. Negotiate carefully with your carrier; bales require a lot of effort to move, load, and stack, and they make a big mess. Settle in advance all issues of labor and cleanup. If you have a crew on hand to load and unload a truck, it will save time and may be necessary before some transport operators will consider moving straw.
Storing Your Mound of Straw
Once you’ve bought your bales, you must decide where to put them. If possible, try to leave the bales in their storage barn until you actually need them. Moving and restacking bales is a lot of work, and can be minimized by having the bales arrive at your construction site very close to the time of the wall raising. If the bales arrive early, they must be stored.
Our favorite means of storing bales onsite is to have them delivered in a transport trailer. You can have the trailer delivered to your site and pay a small rental fee to have it remain there until you need the bales. This keeps your bales high and dry, and if the trailer has been parked close to the building site, you just have to