Councillors have approved a £21m repair scheme for RAAC-affected homes in Dundee.

Work will be carried out on council-owned properties and in buildings where the local authority retains an interest.

The council has agreed to write to both the UK and Scottish governments seeking financial support and a dedicated funding mechanism for homeowners.

Almost 1,000 homes in the city contain the defective concrete - the highest number in Scotland.

The material was used in flat roofing, floors and walls between the 1950s and 1990s.

The Health and Safety Executive (HSE) said RAAC was now beyond its lifespan and could "collapse with little or no notice".

RAAC stands for reinforced autoclaved aerated concrete.

It is a cheaper alternative to standard concrete, is quicker to produce and easier to install.

It is aerated - or "bubbly" - like an Aero chocolate bar.

But it is less durable than other types of concrete and has a lifespan of about 30 years.

Its structural behaviour differs significantly from traditional reinforced concrete. It is susceptible to structural failure when exposed to moisture as the bubbles can allow water to enter the material.

RAAC is often coated with another material, such as bitumen on roofing panels. But this material can also degrade.