I was approached by a client who had concerns with efflorescence in his garage. The white powdery residue left from moisture drying out of his concrete had started to fret the concrete surface, leaving it rough. I had some personal experience with this issue and I told him what my thoughts were to reduce or eliminate the problem. In the end it was decided to seal the slab edge and lay plastic down the slab edge and under the paving to shed the water away from the house.
Once the work had commenced I encountered one of the main reasons it was worse in the area of their garage – when the slab was poured the formwork had created a channel which collected water and was trapped, creating a wet area on the slab edge.
My client was ecstatic, more so because after years of trying to get someone to offer him some solutions and it falling on deaf ears or cant help you.