Thread: concrete surface problems

Efflorescence is pretty common with concrete products, and also clay pavers. The natural salts come through the surface and there's not much you can do in most cases bar either waiting for it to disappear or getting something like "Anti-Eff" which gets rid of it. This can be bought at paving suppliers

Although I have seen some concrete slabs have a whitish powder on top and a weak surface from being too wet during screeding and thus having a higher water content being weaker once set.