I suppose you could put stacked stone below the firebox so it blends in nicely with the surround. (I assume the synthetic stones you are planning to use are noncombustible and can take the heat abutting the firebox.) The challenge will be to remove the hearth without damaging the firebox or anything else to which it is attached. There is always the possibility of a bad surprise. If you haven't done it yet, have the chimney cleaned by somebody who's "certified" (whatever that means), and pump him for information while he's cleaning.

I like this pic from Houzz because it looks like they used a mix of materials, but it's hard to see what is above the mantle. The look is a bit less rustic, they've got the raised hearth and the wood mantle. [Contemporary Living Room[(https://www.houzz.com/photos/contemporary-living-room-ideas-phbr1-bp~t_718~s_2103) by Vancouver Interior Designers & Decorators Claudia Leccacorvi

We finally found a place to rent that has 3 bedrooms and isn't insanely expensive, Yay! I've been playing with the ideas off and on while buying new cars, visiting potential rentals, and working on the house. I talked with the family about converting our 4th bedroom to expand bath and move laundry. My kids were aghast! Where were guests going to sleep? Where were we going to put the desk top (they watch movies on it occasionally, too)? Middle kid thought that it was going to be his room when ready. So, we've decided to keep laundry in the original place. I'm still stealing some of the 4th BR for our MBA, though. The island plan looks fantastic but I kept wanting more storage options once the laundry room had to stay. Also, there is significant cost savings by not digging out concrete for plumbing and installing a beam for the load-bearing wall. Some ideas I had: 1) Widen the existing 32" doorways from garage and into kitchen to 36". Those doors are a huge pain when moving large items through, like the washer/dryer/fridge etc. I can use a barn door or pocket for the kitchen entrance. This will shorten the pantry a bit (measurements are existing on drawing are existing). 2) 1-2 d/w in clean up zone. Bring the existing pass through to counter level so kids can help put dishes away on DR/FR side. Maybe have space for cookbooks under that counter, as well. 3) 30" deep counters 4) Love to keep Mamagoose's 3 panel doors to the patio. With the wall shortened over there, it will bring a lot of light into the house and northern light isn't so bad in the South. I'm not sure what to do with the cabinets between the fridge and sink. I'd like to plan for the future and have some kind of narrow pullout to the left of my 32" all fridge that can be removed if going bigger. The wall on that side can be shortened for french door swing and the pantry remain as sized. Maybe a narrow pantry using cabinetry and store packages of paper towels, grocery bags, etc, above the appliances in the laundry...or in the garage.

If you look at all the caulking and sealant at the big box stores, at least a couple of them will be designed to allow for higher expansion and contraction. Just buy some and squeeze it down into the gap in the floor, and then reinstall the trim. The caulk probably comes in various colors, so don't get bright white that would show up against the floor. It seems that using gray or dark brown would make it nearly invisible. Bruce