When comparing quotations, check they cover the same scope. A price per square metre of covering does not automatically include accessories, membranes, delivery or installation. Request a breakdown of materials, labour and services.
Effective sheet area differs from total area. Roof geometry, overlaps and cutting losses change the quantities. Valleys, ridges and junctions can matter as much as the total area.
For renovation, include structural assessment, removal, possible repairs and waste handling. A comparable quotation specifies the product, thickness, finish, accessories, VAT and exclusions.