Before getting fully involved with the Helm's Deep terrain, I did a quick test wall section for Minas Tirith. This was mainly because I need a Hirst Arts cavern mold for Helm's Deep - and before making an order, I wanted to find out what other molds I would need. I have entertained an idea of covering Minas Tirith walls with very thin Egyptian basic blocks, and if this works, the needed amount of said blocks is huge enough to warrant the purchase of a few extra Egyptian basic block molds. To find out, I created a 14 cm wide wall section, and covered half of it with Egyptian blocks, and the other half with embossed Depron foam. The wall framework is made from 5mm foam board, and the outside surface was first covered with cereal box cardboard (literally!), on top of which the final surface variants would be glued. The crenellations were cut from 6mm Depron and embossed. The height of the wall is 19 cm.
The parapet walk tiling is embossed directly on the foam board:
Here is a close-up of both surface types. I cut out some of the Depron foam tiles and glued them a bit deeper or higher to match the rather haphazard look of the plaster tiles. This effect is not altogether unwanted, but is a bit exaggerated due to me using hot glue to initially attach the plaster tiles on the cardboard backing. That was a mistake as hot glue failed to secure the tiles properly. I didn't bother removing the unwanted glue fully from the cardboard backing, and just slapped white glue liberally over the right side of the wall, resulting in plaster tile covering to be a bit more uneven than it would otherwise have been.
Both sides were painted using four different shades of latex paint. Embossed grooves on Depron were picked up with a pencil, and the cracks received a black wash.
For weathering, greatly thinned dark grey was airbrushed to the arches underneath the crenellations. The wall surface was also drybrushed with almost white latex paint, and the wall received some weathering powder treatment, too.
The end result: the Depron side is almost indistinguishable from the much more laborous side covered with individual plaster tiles. I will thus go with the Depron method, save time & money, and order the cavern mold only...