Cement headache

It seems our builder didn’t really know what he was doing when he built a new cement countertop for our prep bowl. It was treated with one coat of facebrick and stone sealant, yet it doesn’t look as if it’s been sealed at all – it has a powdery coat and the top hasn’t dried out! What can I do to fix and seal it, or will I have to paint over it and forget about a cement finish?

Joanne Sykes, marketing and sales director at Cemcrete, replies The good news is that you can rectify the problem without too much hassle. Apart from the surface discolouration, the countertop appears well finished in the photograph: it’s flat and level with good corners. We suggest you first remove the sink and fittings and protect the walls with masking tape and plastic sheeting. Then follow these steps: 1 Sand off the existing sealant, then allow the counter to dry out completely; this can take one day per millimetre. To test if any moisture is still present, place a clean tumbler upside down