They might also use Exclusive weld pins with integral-cupped head washers. Unfaced boards can then be concluded with reinforced insulating cement, canvas, or weatherproof mastic. Faced boards is usually mounted in the identical way, and also the joints amongst boards sealed with stress-delicate tape or glass material and mastic. - https://freeecogrants.co.uk/how-can-an-agency-help-you-to-get-grants-for-loft-insulation/