They may use Exclusive weld pins with integral-cupped head washers. Unfaced boards can then be completed with bolstered insulating cement, canvas, or weatherproof mastic. Faced boards is often mounted in the identical way, as well as the joints in between boards sealed with strain-sensitive tape or glass material and mastic. https://freeecogrants.co.uk/how-can-an-agency-help-you-to-get-grants-for-loft-insulation/