Schools are falling into disrepair because of a lack of funds, with teachers reporting mould, damp and holes in classroom walls.
A survey of 1,000 school leaders found four out of five said they lack the funding needed to properly maintain school buildings.
Six in 10 said they were dissatisfied with the state of their buildings, and almost a fifth said there were parts of their school estate which could not be maintained at all.
This included toilets, laboratories, playgrounds and kitchens.
Almost two in five said they had to raise funds to cover estate management and buildings.
Some of those surveyed even said parts of their school were out of bounds because they were not safe enough.
The headteachers’ union NAHT, which carried out the poll, said it showed schools are not receiving enough funding.
The NAHT said capital investment in school buildings has been cut by 50 per cent in real terms since 2010, just when many buildings are reaching the end of their life cycle.
The union called for urgent government investment in school estates, saying an additional £4.4 billion a year was needed to upgrade school buildings.
Paul Whiteman, general secretary of the NAHT, said: ‘The crisis of capital investment in our schools has been brewing for 14 years, and it is now clear for all to see.
‘In the last year, hundreds more school buildings have quietly slipped further into disrepair.
‘Our children deserve to learn in safe, comfortable conditions.’
Cindy O’Sullivan, headteacher of Gosden House School, a state-maintained school in Surrey which supports children with special educational needs, said: ‘Our Grade II listed school building is over 230 years old.
‘The building and grounds are picturesque, but it is also rickety, decrepit, and woefully out of date, with leaky pipes, a sky-high heating bill, blocked drains, and rotting single-pane windows.
‘We don’t have the budget to maintain the building.’
Tim Jones, headteacher of Spring Gardens Primary School in North Tyneside, said: ‘Over the last 14 years, our school, which is approaching its 100th birthday, has slowly been slipping into disrepair as funding for buildings has been cut – we are struggling to cover the cost of basic repairs.
‘It’s simply unfair to expect kids to learn, and feel inspired, in classrooms that are damp and mouldy.’
The union is holding its annual conference in Newport, South Wales at the weekend when it will debate issues including school funding.
A Department for Education spokesman said: ‘Schools and sixth form colleges will benefit from £1.8 billion this financial year to help maintain their buildings, taking the total amount of funding to over £17billion since 2015, and our School Rebuilding Programme is transforming buildings at over 500 schools over the next decade.
‘It is up to responsible bodies, such as local authorities and trusts to make their own decisions on investment in their schools each year.
‘We offer additional emergency support on a case-by-case basis to schools which face significant issues that could risk building closures.’
