Ignorable Details: Interior Siding
Here is everything you wanted to know (or didn't!) about installing the siding on the north face of our geothermal greenhouse. Feel free to ignore this post and go to this more general summary post instead (or at least read that post first, which links back to this page)!
Some greenhouses have siding on the outside, and use spray foam insulation on the inside. That's a great solution, but very expensive. Even if we took the chance of doing it on our own (very sketchy whether we could pull it off), the materials alone are more expensive than this cheaper method. In this post, we put siding on the inside of the frame. After our framing inspection we will add board insulation between the frame members, and another full layer of siding on the outside of the insulation.
The siding covers the north face of the greenhouse. Each greenhouse bay is six feet long and eight feet from the top rail to the lower horizontal rail. Each piece of siding is 12' long, and covers three feet (with the edge bumps overlapped). So three pieces of siding, one above the next, will cover two of the greenhouse bays, with enough left over to bend down to the ground. The peak of the greenhouse is about 11' above the floor. Each piece of steel siding is plenty heavy, and all four edges are sharp.
Picture two retirees hoisting the 12'x3' flexible and unwieldy metal eleven feet up, holding it in place, drilling pilot holes, and screwing it in.
I imagined it going wrong in ten different ways as I tried to fall asleep the night before. I woke after midnight, churning the task over in my half-awake brain for hours. This tendency is annoying to both me and people who have to live with me, but occasionally it pays off. Luckily this was one of those times!
The sling shown was the product of my pre-dawn mental machinations. It held the bulk of the weight and provided the safety net that allowed me to push the sheet into place so that Chip could drill and screw it in. We eventually improved on the design by adding a shovel at the center post, which kept the panel straighter, and clamping the panel edge to the frame.
The top panels really were hard work. The sling wouldn't work for the second row, because there was no place to attach it that would hold it tight enough. So we were very pleased to find that the upper panel held it quite well, after snapping the edge bump behind the lower edge of the upper panel. With a clamp on the open end, I hardly had to hold the panel for Chip to be able to attach it. Eventually we worked with two cordless drills at once, and the work started to go pretty quickly.
The bottom row also went on easily, but it went down lower than the gap (the outer layer will be covering a greater distance, so should come more close to the level of the ground). We opted to make the inner layer a little shorter, rather than a little longer than the frame, to avoid having to cut or bury the metal -- we just overlapped the last row. We also installed the bottom row upside down so that there's a finished edge at both the top and bottom of the siding wall.. We screwed the frame members to the bottom of the horizontal rail as we moved down the row.
Back on the first day of installing the siding, there was one part of my anxiety dream that I overlooked in my hyper-focus on that sharp-edged sheet metal. We set up the ladder to drill the first arch to the horizontal beam, and Chip offered me the opportunity to go up and start the job. I deferred, since he is more comfortable and confident working on top of the structure. When he started drilling, the ladder slid a good foot out at the bottom, and a good foot down at the top. Chip kept right on drilling while holding the top of the ladder to the crossbeam. I was not as calm about it. If he hadn't reacted so quickly, and if the ladder had slid another few inches, and if he hadn't held on to the crossbeam, the whole ladder would have pancaked into the greenhouse trench, and Chip could have whacked his head on that steel beam on the way down...
...and if it had been me up there instead of Chip, well, I don't have Chip's confidence and quick reactions...
The thing that killed me about it was that I remembered this was part of my fretting the night before, and in the wee hours I had realized that we should put the ladder legs inside the lower horizontal frame -- which we did, after that close call! (And Chip attached all of the arches.)