They may use Specific weld pins with integral-cupped head washers. Unfaced boards can then be finished with reinforced insulating cement, canvas, or weatherproof mastic. Faced boards could be set up in precisely the same way, and also the joints between boards sealed with tension-sensitive tape or glass cloth and mastic. https://freeecogrants.co.uk/ideas-to-enhance-the-beauty-of-your-home-exteriors/