The union are also opposed to working hours being slashed, and staff working "anti-social shifts".
"IDEA is prone to cutting hours of its staff and is now going through a major restructure.
"Staff are right to be concerned about their jobs and the impact on the people they support.
"IDEA has a long serving and loyal workforce who do their best to support the service users. In turn staff expect IDEA to show them the same measure of support. Sadly, that is not happening," Duncan said.
He said workers were due a pay rise last October.
"Staff see their action as moderate and restrained and are determined that service users, the people they support, are looked after during the action. We have given IDEA extensive notice of the action to minimise the impact on service users."
The strike will start at 8.30am and the last for one hour.