Engineered Stone Benchtop Sagging

Hi,

I have engineered stone over my breakfast bar and it is sagging.

Does anyone know if this can be rectified or if it needs to be replaced? It has a metal bar beneath for support but that also seems to be sagging a little.

The stone is about 20mm thick and I have the installer coming out to look at it during the week but wanted some advice before getting them to look into it.