Unison had argued that the 2.5 per cent rise offered to all staff at the beginning of the year would disadvantage those on low pay. In April, Unison members went on strike at four Quarriers projects, calling for a 3.4 per cent increase or a £600 payment for staff on the lowest grade.
Unison members decided on Wednesday to accept the 2.5 per cent offer after Quarriers management conceded the £400 lump sum payment for the lowest paid. All staff have also been promised a further 2.5 per cent pay increase from October and an extra day's holiday.
The settlement falls 2.1 percentage points below the rate of inflation for many staff. But Unison regional officer Simon Macfarlane, who acted for 600 Quarriers employees - approximately half of the charity's workforce - hailed the settlement as a victory.
"The ballot result is great news as it settles a dispute no one wanted," he said.
Both Macfarlane and Phil Robinson, chief executive of Quarriers, called on local authorities and the Scottish Executive to ensure that charities are paid in full for services they provide on behalf of the state.
Quarriers had argued that it could not meet Unison's 3.4 per cent demand because it was, in some cases, having to subsidise services it was delivering for local councils out of charity funds.