An insulation structure adapted to be positioned above a supporting base layer in a mounted condition, the insulation structure defining a base plane (BP(x,y)) which is substantially parallel to an upper surface of the supporting base layer in said mounted condition, in which the insulation structure comprises: an insulation lamella structure including two or more insulation lamellas, wherein each of said two or more insulation lamellas has a length and a width the length being larger than the width, a base side and an opposing top side, wherein the base side is adapted to be positioned substantially parallel to the base plane (BP(x,y)), and the length of each of the two or more insulation lamellas is positioned substantially in parallel in the mounted condition of the insulation structure, each insulation lamella of the two or more insulation lamellas having a first outermost edge (17a; 17c) and a second outermost edge wherein both the first and the second outermost edges (17a; 17b; 17c) extend along the length and along the top side of each of the two or more insulation lamellas, wherein the insulation lamella structure has a base surface and an opposing top surface, wherein the base surface is adapted to be positioned substantially parallel to the base plane (BP(x,y)), and the opposing top surface is constituted by the top sides of the two or more insulation lamellas and defines an inclining surface having an inclination in relation to the base surface, a difference in distance between the base surface and the first outermost edge (17a; 17c) and between the base surface and the second outermost edge of the at least two insulation lamellas defines the inclination of the top surface of the insulation lamella structure, and that the insulation structure furthermore comprises a separate pressure distributing layer provided on the top surface of the insulation lamella structure and the insulation lamellas are of a fibrous material, the insulation lamellas are cut from a slab of fibrous mineral material with slab top surface and slab bottom surface whereby the insulation lamellas have opposite production surfaces constituted by slab top surface and slab bottom surface and wherein the insulation lamellas are adapted for the production surfaces to extend vertically in the mounted position of the insulation lamellas, characterized in that the first outermost edge and the second outermost edge are parallel and in that mainly a core of the insulation lamella has an isotropic structure of the fibres, while in the production surfaces of the insulation lamellas, the fibres are generally parallel to the production surfaces of the insulation lamella. an insulation lamella structure including two or more insulation lamellas, wherein each of said two or more insulation lamellas has a length and a width the length being larger than the width, a base side and an opposing top side, wherein the base side is adapted to be positioned substantially parallel to the base plane (BP(x,y)), and the length of each of the two or more insulation lamellas is positioned substantially in parallel in the mounted condition of the insulation structure, each insulation lamella of the two or more insulation lamellas having a first outermost edge (17a; 17c) and a second outermost edge wherein both the first and the second outermost edges (17a; 17b; 17c) extend along the length and along the top side of each of the two or more insulation lamellas, wherein the insulation lamella structure has a base surface and an opposing top surface, wherein the base surface is adapted to be positioned substantially parallel to the base plane (BP(x,y)), and the opposing top surface is constituted by the top sides of the two or more insulation lamellas and defines an inclining surface having an inclination in relation to the base surface, a difference in distance between the base surface and the first outermost edge (17a; 17c) and between the base surface and the second outermost edge of the at least two insulation lamellas defines the inclination of the top surface of the insulation lamella structure, and that the insulation structure furthermore comprises a separate pressure distributing layer provided on the top surface of the insulation lamella structure and the insulation lamellas are of a fibrous material, the insulation lamellas are cut from a slab of fibrous mineral material with slab top surface and slab bottom surface whereby the insulation lamellas have opposite production surfaces constituted by slab top surface and slab bottom surface and wherein the insulation lamellas are adapted for the production surfaces to extend vertically in the mounted position of the insulation lamellas, characterized in that the first outermost edge and the second outermost edge are parallel and in that mainly a core of the insulation lamella has an isotropic structure of the fibres, while in the production surfaces of the insulation lamellas, the fibres are generally parallel to the production surfaces of the insulation lamella.