Archive for the ‘Calculating Bales’ Category

Straw Bale Broker Delivers Across the United States

Bales of Straw in the FieldI recently met a bale broker during the New York straw bale workshop. He delivered the bales for our project in Montgomery, and I was very happy with the bale quality. In fact, they were the best bales I have seen all season. I assumed he was a local farmer until he visited the site. That’s when I learned that he is actually a bale broker and that he can arrange for bale deliveries all over the United States. He works with over 120 different farms across the country and many different trucking companies. They not only deliver the bales but stack them on site as well. He is definitely worth the call if you are looking for quality bales.

Here’s his contact information:

Nick Fitzpatrick

845.901.1892 (cell)

800.747.3811 (office)

nick.fitzpatrick@adenbrook.com

www.adenbrook.com

Some Mind-Numbing Facts about Ferncliff’s Eco Center

Last year’s straw bale construction workshop season started with a huge project: the Eco Learning Center at Ferncliff outside of Little Rock, Arkansas. I recently hear from the host of that workshop that the 5300 Sf structure is just about finished. I am amazed at how quickly the project has moved towards completion, especially having read the mind-numbing facts that the host shared with me. It’s a great example of some of the “behind the scenes” numbers that go into building a house. I hope you enjoy the numbers.

Eco Center Front

-The slab has 3,300 fee (.62 miles) of ½ inch PEX tubing that was tied with 5000 zip ties in a serpentine fashion for the 3,900 square feet of hydronic radiant floor heat. The 5300 sq ft building is heated with a wood furnace/boiler with pumps using less than 7% of the power the 12 solar panels can produce.

 -The total weight of the steel framing is 28,000 pounds and it was all hand-carried from the staging area to the slab, then assembled.

 -The Straw bale “toe up” consists of 89; 4×4’s each 10’ in length running twice end to end around the 445 foot perimeter. To fasten these timbers to the concrete, 380, half-inch holes were drilled in the concrete, 380 wedge anchors driven and 380 more holes drilled in the timbers. For “grabbers,”  2,136 large nails (20 penny) were partially driven every 5 inches into the 4×4 timbers.

 -4.26 miles of baler twine was used for “sewing” the walls and re-tying custom-sized bales.

 -556 ceiling panels 30”x30” were milled out of OSB and pre-painted, two coats on each side adding up to 13,900 square feet of surface area painted. This is for the ceilings over the bedrooms.  95% of this painting was done by volunteers. and 95% of that was done by two women (Carol and Jo).

 -25 pallets of rice hulls at 800 pounds per pallet equal 20,000 lbs. or 10 tons of material. This material was toted, poured, slung, scattered for interior wall and attic insulation.  Another perspective:  A five gallon bucket of rice hulls weighs 7 pounds and carried two at a time would constitute 1,429 trips to its final destination.

 -Approximately 43 tons of sand and 14.5 tons of hydraulic lime, plus water were handled into a mixer, wheel barrowed to work area, transferred to scaffold to hawk and trowel to wall. This was done to plaster an 8,888 feet of straw bale wall area three times (26,664 square feet).  It took 120 for the plastering and walls were wetted down at least twice per day during this process.

 -Each of the four large bedrooms employed a different locally available material.  A rock floor was made with rock salvaged from the old camp pool.  A cement stepping stone clock was put in the middle of the floor to make it a “Rock Around the Clock” room.  Another floor was made by putting about 3000 beer bottles bottom up in sand and then mortaring them.  The third floor was made to look like field stone but is actually made from paper mache.  The fourth floor was made with used conveyor belt that was cut into tiles laid over compressed gravel.

Calculating the Number of Bales in Your Straw Bale House

I am often asked how many bales will be needed in my client’s straw bale houses. I too have to know the answer to this on all of my own projects. There are a number of ways to calculate the bale requirements. Click the following link (www.strawbale.com/articles/straw_bales_house.html) to see an article I just wrote for www.strawbale.com on the three most commonly used ways to calculate bale quantities for your straw bale house. My preferred method, the second of the three listed, is given here.

Calculate the number based on square footage of the wall surface area

One way to estimate your bale needs is to go a bit more in depth and calculate the number based on square footage of the wall surface area. In other words, you calculate the total lineal feet of straw bale wall and then multiply that by the height of the walls. This yields the square footage of wall surface. For a gable roof, measure one half the width of the building at the gable and multiply it by the total height of the gable end. That will give you the square footage of the entire gable as if you took the two triangles and glued them back together in the shape of a square at each gable end. You can then remove the square footage of window and door openings from this number. Once you have all of the openings removed, divide the total square footage by the square footage of your bales. For this, consider a 14” tall by 36” long bale would have 504 square inches or (504÷144) 3.5 square feet of bale surface area. This will give you the exact number of bales you will need to build the structure.

Calculating the Density of Your Bales

Most codes require specific measurements for the density of a construction grade bale. The code I work with calls for a bale density of at least 7 pounds per cubic foot of material. The bales I use measure 18″ wide x 14″ tall x 45″ long and weigh roughly 50 pounds. Many bales measure 18″ x 14″ x 36″ and weigh between 40 and 45 pounds. These numbers are for two string bales. To calculate the density of the bales I use, follow the formula below:

Multiply 18*14*45 = 11,340 cubic inches

Divide 11,340/1728 = 6.5625 cubic feet

Divide 50 pounds by 6.5625 cubic feet = 7.62 pounds per cubic foot

You can substitute your bale measurements and weight into this equation to calculate the density of your bales no matter what size they are.


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