MgO boards consist of five layers:
1 - The face surface layer - designed especially for cladding or final painting
2 - Reinforced fiberglass network, which makes the board strength and durability
3 - Filling (includes a magnesium-oxid bonding additive, perlite and wood chips)
4 - The second reinforcement of fiberglass network
5 - The backside layer - designed especially for plastering or as tile backer board