Here it is primed and painted with a Tamiya Panzer Grey rattle-can. All of the roof fixtures have been painted, and some weathered.
This is the tool I made to cut wide lines in masking tape to represent the tar lines. Made out of scrap styrene that was on the Workbench, it holds two X-acto blades securely in alignment. A .010 styrene shim between separates them the proper distance.
I discovered if you took a bottle of Tamiya's Dark Grey, and didn't shake it well enough, it gave a blotchy, faded look. Perfect. I slathered it on with a large brush, not worrying about brush strokes. (If you've seen real roofers appling the hot tar with large mops, you'll understand why.)
I then covered the roof with masking tape, then marked lines a scale 36" all the way across.
I used the double-bladed knife to cut out the lines freehand.
This is a liquid substance to represent lead with faux stained glass. It would dry proud of the roof surface, looking just like tar. The piece of plastic is the screed to force the lead into the gaps between the tape.
The lead applied easily, with good coverage. I let it set til dry, then removed the tape. OH NO! DISASTER! About half of the lead pulled off with the tape. I didn't have that problem when I did a few test runs. However, in those tests I used individual pieces of tape laid side by side, and they were well-burnished to the surface. After cutting the grooves with the double knife, I didn't burnish the newly-cut sides back down. Live and learn.
Anyway, I removed the remainder of the lead, then used a Sharpie to color in the lines. Not really happy with the results, and will have to consider solutions.
Let me know what you think. Thanks for lookin in. Don