They can also use special weld pins with integral-cupped head washers. Unfaced boards can then be finished with strengthened insulating cement, canvas, or weatherproof mastic. Confronted boards can be put in in the exact same way, plus the joints between boards sealed with tension-sensitive tape or glass material and mastic. https://freeecogrants.co.uk/diy-vs-an-agency-to-apply-for-eco-4-grants/