Having recently moved into a new (resale) house, I looked closely at the grout lines on one of the tiled shower floors and noticed many small gaps in the grout lines with an unidentified orange material in the gaps. I've attached a picture.
Obviously this grout is not in good condition and needs to be replaced; however, does anyone know what the orange material in the grout lines is? It appears to be coming from underneath and is raised into the gaps between the tiles, so occupies some of the cavity where the grout would normally go.
Thanks for any suggestions.