Our neighbour Erwin happens to be a builder from Germany. He helped us put the steel beam in. This 5 metre I beam from Zeal Steal cost around $500 but weighed a fare bit more. We had no idea how we were going to get the thing in but Erwin knew, and we had it in within a day, and it wasn't so hard.
First we hired about 10 agro props. Using small lengths of timber to distribute the load we propped up the ceiling either side of the beam - making sure that the beam was inside the props, ready to be lifted into position.
Once we were happy that the roof was supported by the props, we knocked out the last remaining studs. I ground off the nails and put up 50x175 Oregon packer for the beam to be lifted to.
We then lifted one end of the beam up onto a ladder, then the other onto a prop, then the other end a bit more and so on, using lengths of timber to hold the beam at its new height. When it was high enough we put the remaining agro props under it to hold it in its exact position.
We then fastened the beam into the rafters with gal bolts, and put in 90x90 studs at each end, bolted at the top, and making sure to notch out a slight angle at the ends to allow for the curve in the T section of the I beam.
Finally the agro props went back to the hire place and we gibbed up the hole from the chimney.
It was surprisingly easy - thanks to Erwin's experience and has made a huge difference to the openness!