O gymharu â gwledydd eraill yn y DU sydd wedi cynnal arolygon manwl o'u stad ysgolion, mae gan Gymru lawer llai o achosion o RAAC mewn ysgolion. Canfuwyd RAAC mewn dim ond pum ysgol yng Nghymru, o'i gymharu â 231 yn Lloegr a 39 yn yr Alban. Mae’r pump ysgol yng Nghymru wedi ailagor i’r holl ddisgyblion.
In comparison to other countries in the UK that have carried out detailed surveys of their school estate, Wales has a lot fewer instances of RAAC in schools. Only five schools in Wales have identified as containing RAAC, compared to 231 in England and 39 in Scotland. The five schools in Wales have reopened to all pupils.