The report describes four lid designs and a number of demands to a proper lid design. One design is based on a previosly tested lid (Ottrupgaard pilot project) which is considered to be a "low risk" design but with high costs. It is based on a stainless steel - PU-foam - mild steel sandwich construction. The three other designs are all considered to be "higher risk" designs with relatively low costs. They are all based on low cost polymer materials in combination with mineral wool. The estimated prices for the four lid designs is about 1400 DKK/m² for the "low risk" design and from about 560 to 950 DKK/m² for the "higher risk" designs.