We've built a fireplace with a chalkboard-painted flue in our living area. We use the top of the fireplace as a display space, but the render shows watermarks from vases and drinks. Is there a finish we could use that is both heat-resistant and washable?

This is a handy display area, but you do need to seal the fireplace's porous render to avoid those telltale rings. A good option would be to apply a heat-proof paint such as Murobond Paints Cement Paint in a warm neutral shade to complement your kitchen. Let it dry for about seven days, then seal the surface with a clear acrylic sealant. "You could just use the sealant where marks are liable to show," says Rowena Judd, Marketing and Colour Specialist at Murobond Paints. Murobond Paints; 1800 199 299.