A number of issues can go unsuitable when portray grout. First, it takes a really regular hand to color the strains, or else it would stain the encircling tile. Since that is seemingly your first time portray grout, chances are high the strains will come out shaky, making the job look amateurish. Secondly, grout is a porous, sandy materials that is not formulated to be painted. Whether it is discolored, the sealant probably wore off, and the sandy texture is uncovered. This implies the layer you paint will ultimately flake and put on off — whether or not as a result of pounding water from the showerhead or due to cleansing merchandise and scrub brushes — revealing the contemporary grout beneath. The consequence will likely be flaky paint, the place some grout strains are stuffed and others are sanded off, making a hodge-podge mess.
A greater DIY different is to make use of a grout pen, which stains the sandy floor quite than paints it. Nonetheless, whereas that can last more, it would additionally start to put on off over time, making it one other short-term repair. Your finest guess is to resurface the grout as a substitute. This implies you’ll take away and substitute the grout. To take action, scrape off the highest layer; add a brand new, clear layer of grout on high; and seal it to forestall additional staining or harm.