Can You Paint Flagstone . Let the paint dry for a. Change the color of flagstone using a mild concrete stain. Painted Flagstone Floors A DIY Tutorial Dengarden from dengarden.com Can you paint old flagstones? In today's video we can see him painting the flagstone tiles and he has written a little bit more about his process, and how he approaches painting as someone who has never painted terrain before (or at least, before i asked him to!). So i have this beautiful flagstone.which normally i would like but, as you can see, it doesnt match with our house whatsoever.