Hebel blocks or timber frame to support bath

Hi All,

I'm planning on installing an acrylic bath in the corner of a bathroom and this will be part of a bath/shower combo. The walls are brick and thus I'll chase the brickwork to in-set the bath.

I'm planning on using a timber frame to support the bath rim with villaboard skirt but I'm not sure whether hebel blocks may be a better option considering the wet area? The base will be supported by sand/cement.

Any thoughts?

My plumber used hebbel and said it was the best product for the job. but i only took his word for it. seemed pretty tidy and very strong. nice and flat for tiling and one would assume it would insulated the bath some to prevent heat loss??

Hebel doesn't rot, and termites won't eat it.