The party says it will give £10 billion to the NHS to restore hospitals over the next five years, and £7 billion to schools.
Lib Dem spokeswoman Sarah Olney said the funding will be enough to repair “every school in the country”.
“Under Theresa May’s Conservatives, our children are being taught in crumbling schools and our sick and elderly are being cared for in overcrowded hospitals,” she said.
“It doesn’t have to be like this. We will invest an additional £7 billion in our schools. This will allow school budgets to be spent on books, teachers and equipment instead of being diverted to fix leaking roofs.”
The £17bn would come from the £100bn infrastructure fund set out in the party’s manifesto.
This in addition to the £7bn the party has already committed to invest in schools over the course of the next Parliament, in response to rising costs and pupil numbers.
Commenting on the announcement, Lib Dem health spokesman Norman Lamb said: “We have seen with the recent cyber-attack how inadequate the existing infrastructure is for many hospitals.
“Under the Conservatives, money that is intended for capital investment is being diverted to plug holes in day-to-day spending. This cannot be allowed to go on.
“We will invest an additional £10 billion of capital spending in the NHS to fix our run-down hospitals, reduce overcrowding and build and modernise our health service.”