Question: I was just cleaning the fireplace and noticed that there are some small spaces between the brick and the grout (like a small crack) in the fireback area. It's like the brick slightly separated from the grout. Can smoke or CO go into this space (its not very wide, maybe a 1/16th or 1/32nd wide)? Do I need to have the brick re-grouted or can I buy something to fill the spaces? Thanks! Answer: A fireplace drafts upwards, so there is little chance of spillage into these cavities. They sell a product in caulk tubes which can fill these spaces. Try a fireplace store or a hardware store.