Bending Hoops for Hoop Houses
THE HOOP HOUSE DESIGN
The strength and interior air volume in hoop houses are made possible to the millennia-old building shape, the arch. Pipes equally bent into roughly half circles are very strong, especially when properly connected. Arches evenly distribute weight and live loads (wind) to the ground posts and, in turn, the ground.
The types of materials used to construct the hoops vary wildly depending on the accessibility of certain materials, the budget, as well as the farm's individual needs.
HOOP HOUSE MATERIALS
PVC Pipes
- STRENGTH significantly reduced by UV exposure
- Heavy and sustained winds can push a PVC structure to failure.
- Compounded expenses later in the cost and time to rebuild the structure
*Bootstrap Farmer recognizes the need to start on a strict budget but encourages anyone considering this route to do their research.
Electrical Metallic Tubing
- The thin walls of this material do not give you a lot of length to work with.
- EMT makes great individual bed covers for microclimates
- Best for smaller projects
Bootstrap Farmer All Metal Pre-bent Kits
- Stronger gauge metal is available in these kits.
- Double and triple galvanizing, zinc coating, and proprietary coating from top manufacturers *Up to 5X the corrosion resistance than cheaper metals.
DIY HOOPS
For DIY'ers, you can bend your own hoops to save on shipping costs by sourcing poles locally when buying kits like these. The trade-off is the sweat equity of easily bending your hoops with a hoop bender. The other trade-off is that these hoops are made by hand and can be slightly un-uniform. While this doesn't hurt the strength, it is enough to bother the perfectionists among us.
Poles bent from 1 ⅜ top rail found in hardware store chain length fencing sections often are 17-18 gauge thickness.
Some wholesale-type suppliers offer lengths of 21'. While this technically is ok, remember that this is out of spec of the intended hoop house applications.
BENDING HOOPS WITH A HOOP BENDER
The hoop benders are made to bend specific radiuses, and when bending the required amount of 10' poles (10' 6" with swag), they make the most accurate hoops for those instructions.
In other words, both 10' and 12' benders use 2 10' poles, but the radius of the pole bender makes completely different width structures, with the wider house being a bit shorter.
Similarly, a 12' pole bender isn't intended to "bend differently" to make a 14' hoop. Often the best tool is the one that was specifically designed to do a specific job.
When comparing hoops in kits, it is also important to note the spacing of hoops. Some budget manufacturing has spacing up to 6' rather than the much stronger 4' spacing—an important difference in snow and wind loads.
Check out the video Bending Poles for Hoop Houses for a tutorial.
SECURING THE BENDER TO YOUR WORKSPACE
Step One will be to securely mount your bender to a surface that allows you space to work around it. We recommend starting by mounting the bender to a board as a "mounting plate." After this, you can attach the mounted bender horizontally or vertically to any sturdy surface, such as a workbench or existing fence.
Keep in mind if you go vertical, you will need sufficient space, around 4 1/2 feet, beneath to pull the hoop downward.
The benders available on our website come with mounting hardware. You need to supply the board for your mounting plate and the space to hang it.
MARKING AND BENDING HOOPS
Step Two in this process involves marking each of your hoops at the point you will begin your bend. Using a permanent marker and a tape measure, mark each section of top rail 9 inches from the swagged/male end. Because these ends will be placed into your ground posts, you want that bottom 9 inches to be straight.
Step Three begins the actual bending. Insert your top rail, or EMT, into the bender until the marked end sticks out beyond the bender. Bend by pulling down on the long end of the pole.
Continue bending by inserting the pole an additional 18 inches and pulling downward until you reach the opposite end. Once you get close to the end, you will use the extender pole included with your bender to provide leverage to complete the bend. The bend is complete when around 9 inches remain on the non swagged/female end.
Note: We highly recommend you make one complete hoop first before bending the rest of your poles to ensure you have the process working correctly.
ATTACHING YOUR HOOPS TOGETHER
Step four in this process is to attach the two bent top rail poles together to create your complete arch.
Insert the swagged/male end of one of the poles into the open/female end of another. Use a self-tapping screw about an inch towards the female side of the seam where the two join to connect them. This step is a little easier if you drill a guide hole first.
Make sure that your screw is on the side of the hoop and not the top to avoid snagging your greenhouse plastic.
NOTES ON HOOP INSTALLATION
When placing the hoops into the correct width ground posts, the hoops should be about 12" wider than the ground posts. After placing one side of the hoop in one side of the ground posts, a partner pushes in and sets the hoop in the other ground post.
This "spring-loading" of the hoops give them their strength and stiffens up the arch. Don't push the hoops in as far as you can. You will adjust the height before installing the hoop to ground post bolts.
When all hoops are installed, it is very common for them to need initial leveling and plumbing. At this point, it is best to have the keenest eye among you on a step ladder with eyes level with the top of the hoop.
"Eyeballing" the hoops all the way down by pushing hoops in or side to side will get you close but do not expect them to be perfect. They all straighten up when you begin installing the hip boards, baseboards, and ridge poles.
The following statement is true for the entire build but mostly comes into play at this stage. Because all farms, skill levels, and tolerances are variable, hoop houses are designed to have some leeway in them.
These are not Swiss watches that are precise engineering marvels. Hoop houses are rarely perfectly square, plumb, or level. Do the very best you can, occasionally re-do mistakes when your gut tells you.
Once the plastic is on tight, all slight miscalculations go away. This isn't permission to cut corners or skip steps. It's more of a "you'll be ok if you are off a tad." Learning to take farming tasks in stride now will do wonders for your agricultural career long term.