A trip through the Black Country convinced me what I had to do if I wanted big metal walls.
Corrugated iron and lots of it.
Within 10 minutes of my train ride I'd seen acres of the stuff. Mostly it's now black and rusty but once I'm sure there would have been some paint and possibly even a little colour involved.
So, the solution to my problem was simple, all I had to do is make the change. At first I tried to slide a blade between the old covering and the card base. This was a hopeless failure as the glue (Bostick Solvent Free All Purpose) stuck it to the surface too well. All I did was separate the layers of card. This isn't the end of the world. I'm still happy with my work so I'll keep it and perhaps finish the model off some day. After all, all the difficult stuff has been done, it's just detailing and paint required.
So I have made another card shell and this time covered it in Wills corrugated iron. Not the easiest stuff to work with to be honest. I needed more height than the sheet allowed for and splicing in an extra row was a pig of a job with lots of filing and fitting to avoid gaps. The designer had cleverly allowed for the join lines to be uneven as per the real thing but this makes joining sheets vertically challenging. Only after I'd finished did I find some Finecast vacuum formed sheets that would have been much easier to work with !
The little brick lean to was a spur of the moment decision once the model was in place. I felt the building needed a protrusion to break the slab up a bit and some different materials too. It's just plasticard on a card shell again and took only a few minutes to do. No measurements were required and I used a plastic door I had kept in my door pot from an old model. The roof is asbestos for variety, and 'cos I didn't have a big enough bit of the iron sheet left !