GRP Flat Roof Covering This is three number flat roofs carried out on a private household for the home owner in Kent. The covering used was GRP hich is a glass fibre roof covering. Picture 1 This picture shows the side on view of completed GRP flat roof covering . Picture 2 This picture shows the rear of the flat roof .. Picture 3 This picture shows the lower rear flat roof renewed in GRP. Picture 4 (2) This picture shows the second lower flat roof renewed in GRP.