Ribby Arcs & The Sanitized Pig

Rib Assembly Table
(Click images for Big Picture)

There is no flat land where we live. Every thing is sloped. That helps with drainage but makes building things like these 50′ long greenhouse ribs a bit challenging. To ease the process of rib building Will constructed a 40’x16′ rib assembly table temporarily on the east greenhouse foundation. There he and Ben put together the five sections of 2.375″ pipe for each of the twenty-five ribs.

Siege Tower Rib Lift

They then lifted each rib up in succession to me where I reached down from our siege tower platform high above the worksite. That’s from where I took the photo of the assembly table as well – this explains the interesting perspective sweep of the top photo, my bird’s eye view.

I provide the muscle to lift the ribs up to the 21′ ridge line but I had no control over the ends of the ribs which needed to be set onto the feet attached to the greenhouse’s wooden foundation. The people on the ground socketed and bolted the feet to each rib and then I was able to set down the rib, also called rafters, with great relief. Each rafter weighs 225 lbs. The hard part was I wasn’t able to stand quite fully upright to hold the weight in order to make the pipes fit on the feet – I’m the variable spacer in this tower. By the end of the day my muscles, and the top of my head, were sore even with two hats.

First Six Ribs and North Header Beam
(Click images for Big Picture)

To temporarily hold the ribs we put up vertical boards attached to the tractor’s siege tower. These held everything stable until we were ready to start attaching metal cross braces called purloins. Once we got got several ribs and purloins in place we built the north header beam which is attached to the first rib by metal brackets.

Attached to the header and one of the door pillars is a very long 2×8 braced with two diagonals that holds the first rib upright. Purloins attach the ribs together and diagonal pipes further stabilize it so the whole thing won’t accordion like a giant slinky. We’ll be adding a studded end wall that attaches the header beam to the rib all the way up 2′ on-center which will then get sheathing that provides shear resistance to prevent east-west movement, sideways in this photo since the greenhouse runs roughly north-south.

Tractor, Siege Tower, Greenhouse
(Click images for Big Picture)

The three doors below the north header beam create three bays in the greenhouse each of which is large enough for the tractor, a bulldozer or a big truck to drive through. The reason for the trucks is to deliver hay and wood chips. During the winter the deep bedding pack composts to generate both heat and food for the pigs and chickens.

The following year I can then grow pumpkins and the like in the rich soil which will be food for the animals the next cold season. The bulldozer and tractor are then able to push the composted material out the far end into the secondary compost pile south of the greenhouse as needed so that we can spread it on our orchards, fields and other gardens.

To get the siege tower in and out requires taking off the tower’s legs since it is considerably taller than a tractor trailer or dump truck. The height allows me to work on the ridge line, setting purloins, locking in screws and taping joints.

Will Cutting Lumber – Construction without Electrical Power

Although we were getting a steady wind of about 10 mph with gusts into the mid-20 mph range it was not too bad up on the siege tower because to the north west we have wind blocks consisting of Sugar Mountain, Bear Ridge, the two sets of line trees dividing our fields around the home field area and then the greenhouse south field plateau is dug down to get a level spot. All of this lifts much of the wind over us and should help keep the greenhouse warmer. The pigs prefer the south field in the winter for this reason which is why we migrate them to that side of the farm for the cold months. On the other hand, the warmer southernly winds come up the valley all summer and will flush clean air through the greenhouse during the warm months when I’m using it for plants.

The greenhouse will be 38′ wide by 96′ long with a center peak height of a bit over 21′. I call this a greenhouse which no doubt brings images to mind of a hot, humid, tropical closed in space filled with plants in the winter however that isn’t the way this one works. This has a greenhouse frame with a double greenhouse envelope cover for strength and infrared reflectivity back down but the south end of the greenhouse will be open and there are also openings for ventilation along the side walls and the top of the north end. Good ventilation is critical to good health. Humidity must be kept low. Dry is good. This is not a greenhouse for plants but a greenhouse for animals. The pigs and deep pack bedding compost heats the greenhouse along with solar gain. The goal is to make our chilly January and February months more like October or November and to make November-December and March more like September and April. The cover will also keep the snow off of the bedding which helps keep things drier.

One of the things that we have discovered over the past decade of experimentation is that the pigs like a bright sky overhead rather than the dark spaces. They will choose to sleep outdoors for this reason. Given two otherwise equal bedding spaces, they’ll pick the one with a glazed roof over the one with a dark opaque roof. What I think this has to do with is that sunlight lets ultraviolet in which kills off bacteria making for healthier animals. Each day is a sanitization cycle in a brightly lit space filled with natural sunlight. Thus the greenhouse.

Pig Winter Highway

The top priority residents of the greenhouse will be the farrowing sows who will get large open sections in the south end. From there they walk north along their trails to get their water and whey near the center of the farm. Piglets will wean to the well protected middle area of the greenhouse and then shift further north as shoats, growers, roasters and finishers who are able to follow their own trails up the winter paddocks to the whey and water during the cold months. By separating the sleeping areas from the water and whey we ensure the pigs get plenty of exercise and spread their manure and urine to fertilize the winter paddocks which become summer gardens.

Outdoors: 14°F/1°F Sunny
Tiny Cottage: 64°F/60°F

Daily Spark: If you are living a fictional life then the incidence of repeated first names is typically statistically low. The next question is does your name appear in the credits…

About Walter Jeffries

Tinker, Tailor...
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11 Responses to Ribby Arcs & The Sanitized Pig

  1. Sharon says:

    I look forward to seeing the finished and functioning greenhouse!

  2. am in the pm says:

    Bottom photo of pigs in winter highway, is 2nd pig from left Peanut Butter ?

  3. Chiral says:

    Neat. I didn’t realize how difficult putting up the bigger hoop houses was. I built a small (tiny by comparison) 16’x12′ one for my rabbits and chickens using PVC for the rafters and the single purloin and 2x lumber for the base. It’s wonderful on sunny, cold days. I’ve been considering building myself one to do woodworking in next winter, although it probably wouldn’t be as warm without the animals.

    It was by far the easiest structure I’ve built, but the hardest one was a pole barn (although built with only two power tools, an electric drill and a miter saw), so…

    • We also have two 24’x14′ greenhouses of the same design. Putting up this big one is simply a lot more logistics to do safely since the rafters weigh so much more, are so much longer and the heights we must work at are so high. Since safety is paramount, and we have other farm chores and the butcher shop, we proceed slowly. It’s one of those things we just move forward step-by-step.

  4. Pam R. says:

    This is as big as our 105′ x 30′ tobacco shed/barn. It’s probably just as high. But it most certainly has more light, though I couldn’t vouch for the ventilation. Tobacco sheds were built to be wind tunnels for drying tobacco. We tightened it up some, but it’s still got “good” ventilation.

    What I like most about your posts is that you explain the “why” of everything you do, and it’s always comprehensive. Waiting for more photos as the greenhouse progresses…

    • Interesting, I didn’t realize there was tobacco production as far north as you, Pam. We’ll be able to close flaps such that we can control the ventilation from about 70% open down to about 10% open depending on the weather. I don’t anticipate closing it down to the minimum but we’ll have the ability. The air flow is up above the bedding and pig height so it keeps the drafting away from the pigs – this is part of the reason for the high height. Eventually I plan to add one or two inner greenhouses that will give us August in January for piglets to creep to when they want. All this without the fire dangers of heat lamps or combustion heaters.

  5. Bill Beaman says:

    Excellent blog! Thanks. How many sows do you anticipate will farrow at one time?

    • We have had up to a sixteen sows farrow over a short period of a few weeks in the warm months. These were divided up in cohorts of five to six sows each in their own paddocks. We’ve had as many as a dozen sows farrow all within a few days in one paddock, again in the warm months. In an ideal world one or two sows would farrow each week but in the real world they tend to cluster following a boss sow.

  6. Julia says:

    I’m guessing that this greenhouse will allow you to increase sales of spring piglets (in addition to just helping keep things steady through the year)?

    It’s time to start harvesting more income from all the work you have done with genetics over the years!

    • Yes, the main purpose of the greenhouse is to improve our winter farrowing. During the winter the greenhouse will be used for farrowing sows, weaners and then growers. They’ll have that as nesting space but still have free access to the outdoors for their walk to water and whey which is north of the greenhouse by several hundred feet along paths through the winter paddocks.

      In the past we’ve worked to minimize the dead of winter litters but still had to do some to have some piglets born every month because otherwise we run out of pigs in July through September for finisher size. The plan is that the greenhouse will give us fall and spring like farrowing conditions during the worst winter months so we can have more sows farrow then which means more spring piglets and more late summer finisher pigs.

      During the warm months the pigs go back out to the field and the greenhouse will be used for growing plants.

      Getting there is a process. Lots of things to gradually get in place.

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