January 5, 2013 by suchandsuchfarm
Earlier this spring it was decided that we were going to build a greenhouse. We had originally planned to just build a hoophouse. But after deciding to heat it with our wood boiler as well as doing lots of other research, we realized that a hoophouse just wasn’t going to cut it for many of the plans we had. It also would not be as strong or as efficient as a kit model greenhouse (or as expensive…shit). A hoophouse would have taken care of some of our needs but not all. So as it turned out, we needed a real greenhouse. Not just any greenhouse. A really kickass greenhouse. We looked all around the internet and decided to go with a Riga greenhouse kit from Exaco Trading. We got it delivered in the spring but decided to hold off construction until the fall, knowing that we wouldn’t have a real need for a greenhouse until the winter and it would have been so freaking hot to build it in the summer time anyway. One thing we could build in the spring was the radiant heated concrete pad for the greenhouse.
Dave’s old roommate, Robert Corcoran Dixon IV (RCD4) or simply known as Rob/Robby, loved pouring concrete just as much as he loved skateboarding, traveling, drinking heavily and being Irish. He was damn good at all of them. So one day when he was down at the farm (since we was out here every single weekend since we moved in anyway) we asked him if he would help set the forms for the concrete pad. Now, before we go on, let me tell you a little bit about Rob. Rob was an amazing man and a friend to many, especially all of us out here at the farm. He was a mason, an artist, a traveler, a skateboarder, a contributor to such projects as Skatopia, Kingshighway Skatepark (KVHT), City Museum, CementLand and Hermann’s Hole. This dude was also a maniac. A very, very lovable maniac. He loved Widespread Panic, skating concrete “cause it hurts” and drinking at our favorite bar in all of St. Louis, Hair of the Dog. Unfortunately, he passed away in March 2012. We miss our friend so much, but keep his memory alive with us and here at the farm. More about Rob and some videos of him in this post: RCD4th of July Party and How to Smoke a Whole Hog.
So on with the greenhouse! Dave, Nemo, Rob and Greg (co-worker/friend of Dave and Rob’s from the Cassilly Crew, more on Greg later) spent a lot of time prepping the site. The area where the greenhouse was to go was anything but level. It took several yards of gravel and several hours with shovels and a tractor to build up a good spot for the greenhouse. But after we did, our new gravel base would provide us with even more thermal mass than if we had just leveled the dirt. Any heat from the pex coils in the concrete floor that gets through our 2 inch pink insulation board will also get trapped in the air pockets between the pieces of gravel. This creates a big thermal mass of heat storage as well as a drainable foundation that allows water to run off.
After Rob set the forms for the pad, we laid a 2mil plastic vapor barrier and then 2 inch pink foam board to insulate the concrete from the gravel and ground. This will help keep the heat in the pad from escaping. Then Nemo laid the pex coil and zip tied it onto the highway mesh that Dave got from Rick Erwin at the City Musuem (thanks again, Rick!). The coils are placed 6in from the outside edge. This allows a “bubble of heat” to be inside the greenhouse and helps to keep it from leaching out into the colder surrounding ground. We separated our greenhouse into two zones, each independently controlled. This way, we will be able to have even more control over the greenhouse temperature and even have the option to separate it into two separate climate zones if we want to one day. We also left a few ports open in our manifold so that we could run heating coils under the potting benches to provide bottom heat if we need to or build a heat exchanger in a water tank to water Autumn’s little seed babies with lukewarm water (really is better). Options, options, options! Leave ’em open!
By using radiant heat, we’ll be able to heat the greenhouse from the floor without using a lot of electricity or wasted energy. There are many radiant heating design layouts that can be catered to your particular project. All applications are similar but all applications are different. Here’s what ours looked like:
The next step was to pour the concrete pad. This was Rob’s favorite part and sadly, he wasn’t able to be there for it. We decided to pay tribute to him by carving his initials into the pad at what would be the entrance to the greenhouse. As you walk in the door, if you look down, it’s a little off center and a little sloppy… just like Rob.
In the fall we started construction on the greenhouse. Hooray! The greenhouse was designed like a huge, German erector set. It came to us in pieces with two sets of instructions and DVDs. All were very thorough and all were just slightly different than the others. At times, it was a daunting task, but we had some friends come over on a Saturday and had it together by Sunday afternoon (thanks, Abbye, Turkey and Forrest!). And when we did have any questions about anything, we called up Exaco Trading and they were able to help us out (thanks, Andrew!). They have excellent customer service. And we should know. We called them at least 13 times that weekend.
This greenhouse is friggin sick! But, it was also friggin EXPENSIVE! We had planned for a good long while to just build a hoophouse. And in all likelihood, as we get our business rolling, we will have to build a few. However, we decided to go with this Riga greenhouse from Exaco Trading because of its triple wall poly-carbonate and high R rating (R-3) along with many other reasons. This greenhouse really does give you the most bang for your buck. And it better, because it cost a lot of bucks. Well worth it. When the house falls down, that damn greenhouse will still be standing there.
We’ll be posting another blog about the interior design of our greenhouse (benches, water systems, temperature control, etc) very soon!