Reefer Slab – Plumbed and Insulated for Pour
Flowable Fill that is. Due to a communication error we got a type of concrete I wasn’t quite expecting. Instead of slab concrete we received a truck load of what is termed Flowable Fill. Fortunately the pump truck operator caught the error before it was spread on our reefer floor. I diverted it to something else. Not ideal but a way of making use of a bad situation before it got worse. Sometimes you just have to go with the flow. And man, does flowable fill flow. The stuff comes out almost like water. It is very close to self-leveling, but not quite. Unfortunately it only has a strength of about 300 PSI which is insufficient for the reefer’s inner slab.
Our facility is built like a thermos bottle. A thermos bottle within a thermos bottle within a thermos bottle, in fact. The outer most bottle is the outer shell of the building. That outer shell stops the sun and floats at the ambient temperature. Inside of that is insulation and then the structural shell of the building. This will float at about the annual median temperature which is approximately 50°F. That is what we’ve been building up until recently. This spring we began building the refrigerated section, the reefer, which is an insulated box within the northern two thirds of the building. Cool things happen there.
The reefer is thermally isolated from the 50°F structural building and divided up into a number of smaller rooms that get progressively more isolated and colder. Because it is starting with an environment of 50°F, the structural shell, it is easy to get the large mass of the reefer down one more step to below 41°F which are typical refrigeration temperatures. This means we have a refrigerator that is a bit over 7,500 cubic-feet. That’s a heck of a lot bigger than our current 25 cu-ft chest freezer!
So our pour for today was the slab of this inner area – the reefer slab which will float below 41°F. It’s a big thermos bottle.
Hope Perforating Bronchia Tubes
The next two trucks of concrete were what we needed: “Commercial Grade 3000 PSI with Super Plasticizer and Fiber at a Slump of 9 inches”. That is still a very wet mix. The reason we needed such a flowable concrete, as self-leveling as possible, is the reefer is filled with plumbing and access tubes such that it makes screed boarding to level impossible. Instead what we did was to use the marks on the walls and pipe heights to get it as close as possible with rakes and pullers. After we have poured the reefer inner walls we will then be able to setup screed boards and level to the floor drains with just a slight tilt of 1/4″ per linear foot. With such small rooms this will be easy to achieve.
The past month has been a huge amount of prep-work for this pour. We had to get layers of plumbing at multiple altitudes for six rooms all draining right, insulation, access ports, the reefer lungs and self-chilling system, more insulation and sealed so concrete won’t leak in, iron work (rebar) and welded-wire mesh all in place. This was our most complicated pour. The other upcoming sections of the building in the administration and abattoir will feel like a breeze in comparison. In addition to doing the reefer we also poured in the lairage – the holding area for animals the night before slaughter.
The plumbing is very complex and there is a lot of it. After I got it all designed Will and I cut all the pieces, fitted them together loosely and checked the layout. Then I coded the entire system so we could take it all apart and know how to put it back together correctly while we were solvent gluing it for the final fit. I used up four and a half alphabets.
Will Studies Writing on the Wall
As we work I write a lot of notes on the walls to keep track of what’s happening. Cut lists of pipe lengths and diameters. Sequence to-do lists. Check lists. We also keep a set of plans up on the wall with the latest revisions. Traditionally they are called blueprints but I do mine in full-color to get extra meaning in every layer.
Ben a’Puzzling – Trachia & Bronchia of Lungs (green) in Foreground
Where possible we use large 4’x8′ sheets of 2″ pink foam to build up the floor insulation under the reefer. But with the varying altitudes of the pipes this is not always possible. Sometimes it needs just 1/2″. Sometimes 1″. Sometimes 1.5″. In the picture above Ben is using scraps of insulation to create a jig saw puzzle of tightly packed pieces around the plumbing. Then he can-o-foamed it with expanding foam. When we got all done doing all the plumbing and fitting we sealed all of the pieces of foam together and to the walls to create a mold for the coming concrete.
Not all of the PVC piping is plumbing for water. Some of it is part of the lungs for the reefer that allow us to use natural drying air currents to keep our insulation in top form and cold using winter’s air. A lot of the other pipes are accesses for probes and inspection points to the various layers of the flooring and insulation so that I can monitor the system under the different rooms, each of which has its own temperature zone. This is not just a production facility but a research space into some of my ideas on low energy construction. As such I want to be able to get in and look at things, stick probes in, etc.
That funny pink boxy area in front of the kids is the plumbing trench which gives us straight line access to almost all of the plumbing lines for clean outs in addition to the various clean outs in the poured area. You might notice in some of the later photos that the box of pink foam is cut down to its final size leaving the inner box of plywood that keeps the concrete out of the plumbing access trench. This made a mold for the concrete around the trench.
The inner box of the reefer is a building all in its own right that is thermally isolated from the outside world by a thick layer of insulation to minimize the transfer of heat and save energy. But at doorways and the plumbing trench we have a thin connection between the reefer and the outside structure. Since I don’t want the 126,000 pound reefer settling downward a half inch and severing electrical lines or other things there are several pillars spaced around the structural beams of the inner reefer to support the weight. This tube penetrates the foam layer and provided a path for concrete to flow down to the lower slab. We’ll get a very small of heat leakage across this interface but that is better than settling of the inner structure. Theoretically the foam layer should hold over three million pounds of weight but who wants to risk it. Besides, in a thousand years the insulation may evaporate – it’s organic and plastic doesn’t last forever.
Unlike the pillars, the plumbing and access points need to not have concrete flow into them during the pour. Ben discovered that can-of-foam lids make perfect caps for 2″ PVC pipes to keep the concrete out of the ends. This makes it easier to get out test plugs. Not only do they fit just right but they’re bright yellow making them highly visible so we’re not as likely to bump them or trip on all of those pipes. For the 4″ pipe we used five pound cottage cheese pails – plain white unfortunately.
We had a little more foam than we needed for this layer so we hung the extra up along the north wall to get it out of our way. The “extra” will get used isolating the freezer and cooler from the reefer. Bottles within bottles.
One of the last things we did was install rebar along all the beams of the slab and then 661010 welded wire mesh across the entire slab to be poured. Vertical pieces of rebar are setup to attach the future walls. Ben and Will have gotten very good at cutting and bending rebar in addition to their other carpentry skills. I just give them cut plans and they’re off.
You’ll notice there are a lot of stones below the wires. These hold the wires up off of the pink foam so that even when we walk on it the wires bounce back up into the concrete to the height I want them at. Our slaughterhouse and butcher shop make extensive use of Vermont granite.
The blue sill wrap is to protect the PVC pipes from the steelwork.
To the right you can see the outgoing trachia and a vertical rebar as well. This shot is over in the chiller by the doorway coming from the abattoir.
At some point in your life some joker has probably asked you to go get a skyhook. Well, Virginia, there really is a thing and it is quite wonderful. A pump truck makes placing concrete a lot easier.
Will Vibrating and Leveling – Walter Guiding
It makes it so we can get done with our small crew what would otherwise take a big crew or just not get done. Pump trucks are expensive but worth the cost. Shh… Don’t tell Scott Ireland – owner of S. D. Ireland who supplies our concrete and pump trucks. Just kidding, he’s a great guy.
View of Pump Truck and Concrete Truck from North
Notice the pink concrete truck that has pulled up to the left on the road and is waiting its turn to dump into the hopper of the pumper truck.
The slab is poured. I have purposefully left it rough because we’ll be setting up forms on top of this slab to sub-divide the reefer into the carcass chiller, raw cutting room and sausage making room, RTE kitchen, brine room, cooler and freezer. By leaving it rough the walls and final floor can grab onto this concrete. All of the partitions will be made of concrete – no wood in the final building. Once the walls are in place then we can do the final floors that will be screedable over the tops of the floor drains and cleanouts which we’ll be cut to height by then.
In an ideal world we would get exactly the amount of concrete we need but it is very difficult with irregular shapes, think of all that plumbing, to calculate exactly what is required plus some gets lost in the pump truck. The solution is to order a little overage and have a plan for how to use it.
When estimating concrete it is far, far better to be a little over than at all under. I was over so we had the pump truck operator place a pad of concrete in a stone walled area around the north whey trough. This makes it so the pigs aren’t standing in the mud by the trough, gives better drainage and it trims their toenails automatically. I place stone around eating and drinking areas as well as on trails so that the ground doesn’t get as worn and the animals nails get trimmed. This saves me from having to clip nails for three hundred pigs, sheep, etc. No need to work harder than necessary.
Outdoors: 84°F/56°F Sunny
Tiny Cottage: 78°F/64°F
Daily Spark: “Success is not final, failure is not fatal: it is the courage to continue that counts.” -Winston Churchill
I am exhausted…just from reading your post. How do you do it Walter ? How do you keep everyone motivated and willing to work so hard all the time ? Seriously, when and how do you relax. ? Excellent post, fantastic photos in sequence. Well done…Holly ?
Hmm… I’m not sure how to answer or really which question. It is a way. Chez Tao. Holly says I am the engine and rudder and that she is the keel. It works. We are very organized and To-Do list oriented. We each have things we take care of. There is the daily chores list. There is a current projects list of other things we need to do. I manage a master list that looks out the next few decades, becoming more detailed as it is closer. I work to try and keep us focused. Everyone works very well both together as a team when needed and independently at their own things. This allows us to do things we couldn’t do separately.
We teach from a very young age. We also teach the kids early on to say “What can I do to help?” and to actively look for things that need doing. Yet at the same time we take time to read books together out loud every day, eat all our meals as a family. Our days are divided between chores (maintenance), construction (new things to improve stuff), research/learning and relaxation. Theoretically we take Sunday off part of the day but in reality Sunday can fall on any day of the week and is very weather dependent. We go with the flow.
All that said, there are ups and downs, harder things and easier times. Getting ready for a concrete pour is something where it can feel like we’re working really hard for a long time to get forms and such in place but not making any advancement. Then one day everything is finally ready, we pour and voila. Instant progress – A feeling of satisfaction. Fencing is another example like that.
Added thought: Another thing that definitely motivates us all is we have a vested interest in all that we do. The farm isn’t just our business, it is our home and it isn’t just our home, it is our business. It is a livelihood and a lifestyle. Both Holly and I wanted this decades ago. I started planning it when I was 15 years old. The kids talk about their long term plans on the farm and where they want to see things go. Together we’re making it happen. Maybe that is the real answer.
Wow, that is quite a family feat! Congratulations and best wishes with the remainder!
Fantastic work!!! Are the PVC pipes not effected by being in direct contact with the concrete??? I guess cracking is not an issue since there won’t be any temp fluctuations in the concrete but what about when it is curing, or pvc deteriorating over time??
The possibility of the concrete cracking or the PVC being damaged is something worried me. I read up on it a lot and in the end did my own tests. After many years the test pieces of PVC are doing well so I’ve decided it works.
I use fiber, WWM and rebar to help the concrete resist cracking along with sufficient depth of concrete. The biggest problem I’ve read about is having too thin a pour and then getting crack lines over pipes. PVC and concrete do not have the same rates of thermal expansion. You may notice I used some sill wrap to allow for expansion and protect the pipes in key places.
I’ve got test access ports so I can continue to monitor things and ever piece of PVC’s actual final position is carefully mapped to the nearest inch so that I know where they are should it ever become necessary, Heaven forbid, to do interventions.
Lastly, as you noted, the area is very thermally stable and that should help.
As always, I love seeing what you and your wonderful family are accomplishing. Love seeing Hope with the drill! Raise them up in the way they should go… :D
Wow! What an amazing lot of planning and work. I’m exhausted, just reading it! :) You all can be very proud of what you’ve done.
I echo the abovt, it’s even more amazing given the routine of work which has to be done every day.
You didn’t answer Donna’s last question though.
You are right that having to also do the routine farming chores, deliveries to stores, homeschooling and such certainly does cut into the time for construction which slows things down.
We don’t do construction full time and as such it takes longer than it might take a “professional”. But I’ve paid professionals before and seen the mistakes they’ve made. I would rather do it myself, take a little longer with my limited time and get it right doing a better job. This isn’t to degrade all professionals, I’ve known and worked with many professionals and non-pros who do excellent work. But I’ve had too many bad experiences to hand off things I can do myself. I have a lot of experience with what we’re doing, gradually doing more complex projects. Besides, I like the work and doing it at my pace. It’s not just a job, it’s an adventure.
Another thing that slows us down is simply money, or rather the lack there of. Some people might say that it should take us only a short time to do something but they’re thinking fully financed. The fact of the matter is banks are not lending in the current economic climate. Our government turned around and used trillions of our children’s dollars to bailout those bankers and other big corps who were “Too Big To Fail”. But I suffer for it. So because I don’t have the cash to buy the next set of trucks of concrete I go more slowly and pour walls as we have the cash through the earnings of our farm, our CSA Pre-Buys and some loans we’ve gotten from individuals. I appreciate those people who have shown faith in our project be it $15 or tens of thousands of dollars. Every little bit helps – no credit to the banking industry or government there.
We are also doing some unique things that make conventional form framing techniques and tools not work. This means things take a little longer and looks a little different than a professional might expect. On the other hand our local concrete company is very impressed with our form work and our project. They’ve been out here, both their engineers, managers and workers to deliver concrete, go over upcoming pours and just to see what we’re up to. They’ve seen our other projects too and been impressed with those. The fact is, it works. We avoid blowouts and as the concrete truckers have told us repeatedly the pros blow out many times. Nice boring pours I like.
Lastly, there is weather. Someone down south might not understand that in the northern Vermont winters outdoor construction pretty much shuts down state wide. We can get fourteen feet of snow (typical year) that compressed down to a hard pack about four feet deep and last from November through April or even into May. It gets as low as 45°F below zero. Do not touch metal with your bare hands. I have poured concrete for over twenty years, often in sub-freezing temperatures when I had to do so. It isn’t pleasant. I try to avoid it in the winter as does everyone else up in the north country. The concrete plants mostly shut down in the fall because business falls off so much. We have a short growing season and a short construction season. Both happen at the same time. This slows down projects. That’s life. We keep plugging along.
Very exciting to see it all coming together, and everyone involved!
As always, such an inspiration.
The notes on the wall reminds me of various theatrical construction builds that I have been a part of in the past, only this one is more complicated by far. One of these builds is where I first heard about the skyhook gag. The other one was snow tires for the Genie lift.
Ah, I haven’t heard of snow tires for the Genie lift…?
Does your concrete supplier not allow you to do a call-back on your yardage? I mean, it’s fine if you have somewhere else you want to pour a little extra mud but if you don’t, or don’t need but a tad, having a couple of extra yards can be a stiff hit in the wallet. We figure our mud close and then tell the dispatcher we will have a clean-up truck (call back). After you have about poured out and know one truck is going to finish you up, you can measure and calculate that last bit (much easier and accurate since it’s a smaller space) and then call for your clean up. Most concrete plants expect this on a large pour. It allows for much less waste and expense.
I also don’t quite understand why you don’t top off your slabs and finish them on your first pour instead of risking that cold joint? You can just float in a keyway where your walls are going to go. You know where they will be and have stubbed up your rebar, I assume, so running a keyway is easy. This locks in the wall and lets you have a slick finish on which to better secure a wall form. The risk of blowing out a wall because they will not attach firmly to a rough floor or footing is messy and a pain in the you know what. Secondly, hiring a couple of good finishers to finish the slab the first time must be waay cheaper than paying for a pump truck to come out again for yet another pour, even if it is just a line pump..
Regarding the finishers and the pump truck repeats, what we do is combine several pours. He’s not just here for one thing in most cases. That amortizes the pump truck cost. Even then it is cheaper to get the pump truck than good finishers. Labor is very expensive. Additionally we do not want a finished surface at this point and the final surface won’t be concrete – we’ll be epoxying. To meet USDA meat processing regulations for HACCP/PR and SSOPs we’ll be using organic acids like citric acid (from oranges, etc), lactic acid (from milk), acetic acid (vinegar) to kill bacteria. This gets on the floor and it eats concrete. In fact, acids in general eat concrete. Thus we need a coating over the structural concrete and that coating must offer good traction since the floors are often wet during working times. To lay down the four layers of epoxy coatings we need a rough not a smooth surface.
The reason we pour in the order we do is that we’re doing the thermos bottle effect where there is little contact between inner and outer sections due to the insulation. This is not at all like building a house. The plant has to be kept cold and that is a very high energy cost which will go on year after year. By take a little more time now we can build something that saves tens of thousands of dollars every year in energy consumption. I debated pouring it all at once and figured out how but the risks were too great. Better to go a little slower and be sure we don’t have a blow out. Additionally, the inner most floors are different than the slab, are required to have curbing with coving above and below, etc. The USDA regulations make this a lot more complicated than pouring a basement.
As to call-backs, yes, they do offer them but it isn’t efficient. We are a long ways out and there is always some concrete lost in the pump. To do a call back would entail cleaning the concrete pumper truck out completely to protect his equipment while we order the extra on the “call-back” truck which would take almost an hour to arrive. That’s just too long – way longer than the pumper guy wants to let concrete sit in his hoses.
The pump is well worth it. We can’t get the concrete where we need without the pump truck so we must deal with that. My solution is I just plan out other projects. I virtually always have something else on the farm that needs doing so it really isn’t wasted. In this case the small amount of overage is used for the concrete pad that saves me time every month trimming nails. That means I can do something more interesting.
So the kids have long term plans like building their own house on the land?
It is a very impressive bit of engineering there.
Well, I’m actually not comparing your pours to a basement or building a house. :) I’m going by my 20 years experience pouring slabs/ foundations for industrial freezers, food distribution centers etc. in which insulating slabs, cold storage, etc. are common engineering. But, that’s okay; it’s however you want to do it. And at any rate, either method wold still allow for keyways.
As you say, both will work. Since I’m trying to do a lot better than the standard industrial freezers this is a bit different. Conventional systems waste a tremendous amount of energy. My goal is to use as little electricity as possible. We may be able to get away without running compressors for much of the facility for most of the year. That keeps money in my pocket and I like that.
Part of what I did in designing the reefer was study a lot of reports about failure modes of commercial refrigeration systems and then work to design ways to prevent those failures. Some of the complexity results from that.
Additionally, most commercial freezers are simple big boxes. Ours is boxes within boxes all within a very small space. The USDA defines very small scale meat processing plants which are a lot bigger than what we’re doing. We’re building a nano-scale plant so to speak. A lot of things are happening in very small spaces. As such it is customized to a much higher degree. It requires more work now perhaps on some things but that will pay back in the long run and less space is wasted in unnecessary walls.
The normal (according to government and industry reports) cost of building a facility is 2.5 to 4.5 million dollars. We’re still on budget for a mere $150 thousand dollars. Yes, our labor is not counted in that and we started out with the land so we have some inherent cost savings. Yet, we are bringing it in for an order of magnitude less than they talk about doing it. This was one of the problems when I talked with the USDA loan program and VEDA – they insisted the project can’t be done for such a small cost. They’re wrong in part because they think too big and in part because they think conventional construction instead of working smarter.
Remember: People also say you can’t make a living farming. You can’t make a living raising pigs. Pig’s can’t eat grass. There are a lot of impossible things that happen before breakfast. :)
annie i take it that is 20 years of traditional cold storage and i am willing to bet the brooklyn bridge that you werent the engineer or foreman. glad you are willing to admit it can be done differently but time to recognize something that might be not just different but also better. how many of thoses systems you installed are now having to get torn up, fixed, replaced?
This is my all time favorite post! Thank you for the entertainment Walter.
Karl! I am so glad to hear you are up and about after your surgery. May you progress well with your recovery.
Those corrugated green sheets that form the “lungs” — what are those? Plastic? What are they normally used for?
Corrugated fiberglass roofing panels. Excellent strength to hold a couple hundred thousand pounds of concrete up in the air.