Hello! My husband and I have bought a house that we will gain access to at the end of the month. The house's layout is such that one of the bedrooms and the living room with access to the patio are a level down from the kitchen. Currently, there are two steps on one side of the fireplace and completely open on the other side, which poses a fall risk for our youngest child who will soon start walking. We have not yet decided what we want to do there, whether we should put up plexiglass/glass railing, enclose it, or build something custom. In the meantime, we thought we would put up a baby gate there. Now to my question - is there anyone knowledgeable who knows if there is any risk of drilling into the plaster/mortar (yes, what is the material really?)? I assume the chimney flue should be quite a bit away from where we want to mount the baby gate! Does anyone have any knowledge or tips and advice? 
attaching a picture of how it looks and where we think we need to drill!
attaching a picture of how it looks and where we think we need to drill!
Regardless, drilling so close to the edge is not a good idea, there's a high risk of it cracking.
Tricky/dangerous solution, it hardly complies with building regulations...
Tricky/dangerous solution, it hardly complies with building regulations...