The dilapidated state of St David's Secondary School has shocked the County's politicians.
Stephen Crabb MP and Paul Davies AM were aghast when they were shown round the school by head teacher Ray Bevan.
"We were both appalled by the state of the buildings at St David's School," said Mr Davies.
Parts of the school, which has 464 pupils, date back to 1895 but the majority was built in the 1960's.
"There was rain coming into the hall and into two or three of the classrooms," added Mr Davies. "They had re-carpeted a classroom but hadn't been able to fit it up to the wall because the wall was still leaking."
Mr Crabb said: "The staff and governors of the school are clearly trying their best to keep the school decorated to a high standard but the buildings urgently require some serious investment."
Head teacher Ray Bevan says repairs are carried out but they are just sticking plasters when major surgery is needed.
"It's very piecemeal," he said. "The metal windows have rusted through so they've put sealer on the outside to stop the rain coming in rather than replace the windows.
"Where there was a damp wall with plaster coming off they just clad the inside of it. They don't really tackle the root of the problem."
Parent Nancy Stott has a daughter aged 13 at the school whose classroom has just been condemned. "It's a wonderful school and the quality of the teaching is excellent. It's a shame this isn't underpinned with some proper investment in the fabric of the buildings."
The school also has no indoor sports facilities for pupils. "Over the years St David's School has produced some outstanding sporting success stories," said Mr Crabb. "It is sad to see just how limited the opportunities are now for the pupils to enjoy PE throughout the year."
Head teacher Ray Bevan says it is very tough on the children. "The hall is only fit for table tennis so when it rains or we have exams in the hall during PE lessons the pupils end up sitting in class discussing sport, we can only do the theory," he said.
Despite the problems at the school they still achieve excellent results and scored highly in a recent inspection. "We got seven grade ones in our inspection so the quality of education here is superb despite the problems," he added.