Please be aware that green or red algae will soon form in a birdbath that holds water. Algae will not destroy mosaic but it does tend to stain the grout. To remedy this, simply change the water regularly and clean the birdbath using a washing up brush and if necessary, a bathroom cleaning product like Cif. Your bird bath will look like new again! However, please don't forget to rinse well after cleaning as birds both drink and bathe in the water!

I cannot guarantee that the grout will withstand frost. It's better to be safe than sorry; I recommend that you store your birdbath in your shed, conservatory or garage if the temperature drops below zero.