Croeso i Peirianneg Sifil GelliMae’r tudalen wefan yma ar ganol cael ei chyfiethu. Felly er mwyn i chi gael gwybodaeth am cwmni Gelli allwch fynd i’r cyfieithiad Saesneg hyd nes bydd y cyfieithiad wedi ei gwblhau. Neu cysylltwch a’r brif swyddfa. Edrychwn ymlaen i glywed ganddoch.

AccreditationsThe company is accredited to ISO 9001; ISO 14001 and will be accredited to OHSAS 18001
in June 2015; CHAS; Constructionline; Investors in People and Considerate Constructors
Scheme. We are also members of CITB ConstructionSkills and CECA (Wales).