The standard thickness for membrane lined insulated gutters tends to be anywhere between 30mm and 100mm, with a membrane thickness of 0.6mm to 1.2mm.
The external facing PVC painted or galvanised insulated gutter is usually 0.6mm thick, and the internal liner slimmer at 0.5mm.
Taking Kingspan membrane lined insulated gutters as an example, the U-value (W/m²k) depends on the core thickness. Kingspan insulated gutters with a 30mm core will offer a U-Value of 0.67W/m²k, whereas a thickness of 100m offers 0.21W/m2k.