Amateurs do this sort of thing all the time and this is not, not, not an appropriate fireplace repair.
Fireplace boxes get hot and cool down. A lot.
As such things expand and contract and what very often fails in a fireplace are mortar joints.
The cracking and loosening of mortar has to be handled carefully. Trying to remove it with force can also encourage the bricks to shift out of place.
It's best to have a professional repair all this.
Flippers and homeowners are usually not trained.
Repairs have to be done with materials that withstand high temperatures!
Any mortar used must be labeled as "heat resistant" or "refractory." There is a caulking made with silicates for small repairs. It dries very hard.
A professional will carefully remove any loose mortar and vacuum the gaps completely.
Then they spray it all with water and trowel or pipe (like cake decorating) the mortar into the gaps. The mortar is then finished with special edgers to create the desired look. Sometimes they tape plastic over the mortar repairs to make them dry more slowly, and therefore cure to be harder. They are very good at it! A professional knows what materials to use!
What should NOT be used are materials that can burn!
This job "repair professional" used a very soft caulking. I could squish my fingers into it! It wasn't even silicone...
This stuff isn't fireplace mortar. Is it flame proof? Is it labeled to contain the proper fireplace silicates for use in this application! The house has been on the market for weeks - why hasn't it hardened by now?
My recommendation: fireplaces are big deals. They have to be investigated as carefully as possible. This particular fireplace flue had dangerously thick soot and creosote build up as far as I could see. It has not been cleaned in a long time! Had a professional chimney sweep done the work you see here that flue would have been swept also! This "repair professional" (i.e. Flipper) went to the store to find a caulking that looked like it has a mortar color and squirted it in there! And now wants someone to buy it. Get an inspection! Be safe!
Jay Markanich Real Estate Inspections, LLC
Based in Bristow, serving all of Northern Virginia.
Office (703) 330-6388 Cell (703) 585-7560