A seal assembly for a gas turbine engine comprising: a seal (69; 169; 269) including a main body (170; 270) extending circumferentially between opposed mate faces (178; 278), the main body (170; 270) including a sealing portion (177; 277) and an engagement portion (179; 279) extending outwardly from sealing portion (177; 277) along at least one of the mate faces (178; 278); and wherein the main body (170; 270) includes: a core (192; 292) including one or more core plies (CL) having a first fiber construction and arranged to establish an internal cavity ; an overwrap (194; 294) including one or more overwrap plies (OL) having a second fiber construction and arranged to follow a perimeter of the one or more core plies (CL) to establish the engagement portion (179; 279) and the sealing portion (177; 277), and the second fiber construction differing from the first fiber construction; characterised in that the first fiber construction establishes a first target fiber volume fraction, the second fiber construction establishes a second target fiber volume fraction, and the first and second target fiber volume fractions are equal to or greater than 0.30, and wherein the one or more core plies (CL) are triaxially braided, and the one or more overwrap plies (OL) are biaxially braided. a seal (69; 169; 269) including a main body (170; 270) extending circumferentially between opposed mate faces (178; 278), the main body (170; 270) including a sealing portion (177; 277) and an engagement portion (179; 279) extending outwardly from sealing portion (177; 277) along at least one of the mate faces (178; 278); and wherein the main body (170; 270) includes: a core (192; 292) including one or more core plies (CL) having a first fiber construction and arranged to establish an internal cavity ; an overwrap (194; 294) including one or more overwrap plies (OL) having a second fiber construction and arranged to follow a perimeter of the one or more core plies (CL) to establish the engagement portion (179; 279) and the sealing portion (177; 277), and the second fiber construction differing from the first fiber construction; characterised in that the first fiber construction establishes a first target fiber volume fraction, the second fiber construction establishes a second target fiber volume fraction, and the first and second target fiber volume fractions are equal to or greater than 0.30, and wherein the one or more core plies (CL) are triaxially braided, and the one or more overwrap plies (OL) are biaxially braided. a core (192; 292) including one or more core plies (CL) having a first fiber construction and arranged to establish an internal cavity ; an overwrap (194; 294) including one or more overwrap plies (OL) having a second fiber construction and arranged to follow a perimeter of the one or more core plies (CL) to establish the engagement portion (179; 279) and the sealing portion (177; 277), and the second fiber construction differing from the first fiber construction; characterised in that the first fiber construction establishes a first target fiber volume fraction, the second fiber construction establishes a second target fiber volume fraction, and the first and second target fiber volume fractions are equal to or greater than 0.30, and wherein the one or more core plies (CL) are triaxially braided, and the one or more overwrap plies (OL) are biaxially braided. <EOS>