12in 300mm Premium Concrete Rock Face Gravel Boards. Enhance the longevity off your wooden fence panels with our concrete posts and gravel boards. Concrete posts and gravel boards offer the best protection against the elements and are proven to last longer than their timber counterparts. Rock Face gravel boards isolate your panels from ground contact which significantly reduces the chances of them being affected by water damage. Concrete fence posts remove the need for nails, brackets and fixings and will provide highly robust support to your fence panels.