Cutting the Wall and Installing Some Steel

 As I mentioned previously, the only piece of "Building" work that I had no intention of doing myself was the cutting down of part of the back wall, and the installation of some heavy steelwork to replace the existing purlin. This was the original back wall:

And as you can see, the installation of the purlin (which was supporting a large part of the entire roof!) looked like this - not ideal:

In order to give myself more internal space in the studio, I wanted to cut back this wall - but this was not something I fancied doing myself. So, we got a quote from Joe (a local builder), who said that he was happy to cut back a whole two blocks worth, with the proviso of adding some steel box column to the front of the wall to help take the weight.

The purlin would then be replaced by what is called a Flitch Beam - two pieces of 2by8 timber beams with a sturdy steel plate (the Flitch Plate) bolted in between to give it the necessary rigidity. The 2by8s then just serve to prevent the steel from flexing horizontally.

Here's a picture of the steel box column that would go in front of the wall - for reference this weighed about 200kg. The flanges would be used to bolt it into the floor on one end and to connect to the Flitch Beam on the other end, essentially bearing the weight of the beam and thus the roof.

Throughout the work, I was assisting Joe; the first thing we had to do was to prop up the existing roof structure with acrow props holding up a scrap piece of 2by4 that we cranked up to take some of the weight of the rafters. This arrangement can be seen below, with the acrows circled in red:

Joe had then hired a manual lift that we would use to lift the Flitch Beam into position (after having lifted down the existing purlin). This can be seen below - the blue contraption which is being manually wound up just off camera.

Here you can see the Flitch Beam being carefully lifted into position on top of the blue crane arms:

Once the new Flitch Beam was in position and still supported on the crane, Joe then proceeded to cut back the existing wall using a chop saw (similar to a very large angle grinder) with a diamond blade - like you can see below. This was very dramatic to watch as it created an enormous amount of dust/sparks/noise, which was made all the more intense by Joe not using one single piece of PPE!

After the wall was cut, Joe installed two padstones at each end of the Flitch Beam (which was now the new purlin). These are essentially very strong concrete blocks that are used to distribute a point load without the risk of crushing what is below it. In our case they helped redistribute the load from the purlin along the remaining portion of the blockwork wall.

Finally, you can see the finished result below (ignore the red plasterboard crane in the foreground). The work had achieved exactly what I required: a much less protruding wall which would create more space in the studio, and a much stronger and more secure purlin that we could rely on to take our additional ceiling load.

Next up - Strapping in New Rafters