That is the answer to the question in the last post. How do those steel pipes and plates support a vegetable garden?
Well, let’s take a step back. In April, I was contemplating our dream of a green roof, or more precisely a vegetable garden on our roof. A structural analysis showed that this would be possible at reasonable cost.
The analysis also showed that we would need additional steel columns in the basement to support the weight transfer from the roof. Since then we had excavated and poured the required spread footings. All that’s missing now are the actual pipe columns.
The materials are on site and we have the expertise of Yuval and Adam who will prepare and install the assembly. This involves quite a bit of grinding on the pipe column ends to get them ready for the weld joints.
In the basement, the existing steel work got polished at the various welding locations. Once that was done, Yuval clamped and tack welded the top plates of the pipe columns to the existing WF steel beam that runs from front to back through the basement.
We now could transcribe the location of the bottom plate on the spread footing pedestal with the help of a plumb line, set the plate in place and squeeze the pipe column between the top and bottom plates.
Installations like this call for non-shrink grout under the bottom plate to fill any gaps and make the installation a little easier. Yuval exercised great precision when measuring the lengths of the columns.
So much precision that we could, with the help of a hammer and wood block, nudge the pipe column between the two plates. I was ready for the non-shrink grout, but I had no place or gap to put it.
Once we had the pipe column centered and plumb, Yuval finished the welding around the top plate, welded the pipe column to the top and bottom plate, and welded the stiffener plates into the existing WF steel beam right above the columns.
That is a lot of welding with a lot of sparks close to a lot of 100 year old floor joists and other framing lumber. We were very careful to have a water sprayer and two fire extinguishers nearby – very nearby.
Last task: painting all blank steel with primer and anchoring the bottom plates with ¾ inch bolts into the spread footing pedestal.
We have support in place, but no vegetable yet. Hmm, I wonder when we will get our first harvest?