A method of sealing a joint between components especially in an aircraft comprises the steps of identifying the sealing gap to be sealed; selecting a suitable sealing material having a fractional maximum sealing thickness and a fractional fully-compressed thickness and selecting a suitable thickness of that sealing material, based on a consideration of the fractional maximum sealing thickness and the fractional fully-compressed thickness of the sealing material and on the sealing gap; locating, between the mating surfaces of the components to be sealed, the suitable thickness of the suitable sealing material; and fastening the components together.