1. Begin with a piece of cardboard as a base. I use cereal boxes as a cheap and readily available source of cardboard.
2. Cut strips of cardboard into 1 cm wide strips. Then cut the shingles into the strip. Vary the width of the shingles, and do not cut all the way through. Leave the shingles attached to each other.
3. This next part is an optional part to the process. Go back over each strip and vary the shingle length. Cut off the ends of some shingles, leave others full length. Cut them at varying angles, and lengths.
I do this depending on the style of the project I am working on. If I want an older, more worn, dilapidated, crumbling, or even just a more impoverished look I will use this method. If I want something newer, well kept, or affluent, I will skip this step and leave the shingles the same length.
4. Using PVA glue (aka. white glue), attach the strips to the roof base you made in step 1. Layer each strip so that it is on top of the strip below. If you want to create a more worn look, glue some of the shingles flat to the ones on the row below, while pulling up on others and exposing a small gap between the shingles. Continue until you reach the top.
5. The same process can be repeated for any type of roof. With this one, I actually cut the base with a curve to create the idea that the ridgeline had sagged with time. I tried to reflect that sagging in the shingles themselves by curving the rows of shingles as I attached them to the roof.
6. The peak of a slate roof is different than that of an asphalt modern roof. Being a stone, slate does not layer in the same way that a normal shingle would along the ridgeline. When making a ridgeline, I cut single shingles and arrange them side by side along the ridge. It is important to make sure that the shingles on either side butt right up together at the peak. Any gaps that remain can be filled with spackle, clay, or some other filler. Keep in mind that a certain amount of unevenness works well. Roofs like this were handmade, and if the rows are too even, or the stones too uniform, you will find it doesn’t look quite right. A little imperfection goes a long way.
7. Once the roof is constructed I paint it black, then drybrush it successive coats of lighter and lighter grey.