What is welding? and, it's good to have a garage

It has been raining steadily for over a week! The rain has delayed almost all outside work, because the next phase involves electrical currents and super-hot temperatures. Engineers can skip the rest of this post.

For the rest of us: As posted previously, most of the weight of the two new floors will rest on one old column, one new column, the back and side walls (sans parapets). The structural element that will connect the 2 new floors to the columns is a long square tube. (The square tubeness of it is clever, unique and important, but incomprehensible.) The tube came in two pieces - together they are longer than footprint of the new floors - the end of the tube will remain visible on the roof. The tube must connect to the columns by connecting to the beam that currently sits on the columns and supports the roof. (photo 2 is out of date, just to remind you what the green beam & columns look like on the inside.)

Problem: the tube is 12 inches wide, and the beam is 8 inches wide. It would be impossible to reach around and under the tube to stick it to the beam from above; and sticking the tube to the beam from below would make our apartment unlivable. Solution: make the beam 'wider' by welding flat bars along both edges, creating a mounting surface that is about 14 inches wide.

The flatbar is first welded to the beam and then welded to the tube. A third party testing company had to determine the exact composition of the beam and tube and opine on the exactly correct composition of welding wire. The welder uses extreme heat to melt the beam and the flatbar, and to mix the two molten metals with molten wire. The welds are about 4 inches long, about 3 inches apart. The welding started today when the sun came out.
Or, as D's complete blog post for today would have said: "This is the first welding of the flatbars to the existing girder."

While waiting for the rain to let up, the crew managed the delivery of all the guage metal - the steel studs and joists that will become the frame of the upper foors. ('Guage' means the metal is less than 1/8 inch thick; if it were thicker it would be 'plate.') The studs range from 2x4" to 2x12", all about 24 feet long. They completely fill the garage. Most will be cut to size in the garage and carried up to the roof by any means necessary.