You're measuring from the actual opening of the fp and not the outer perimeter of the insert, right? May give you more room to play with.

My hearth is 13" from floor to bottom edge of insert. I was worried about mantle being too high also (tv above). Not sure what our insert instructions say, but code dictates a shorter distance of 7" non combustible. That'll put the wooden mantle right around 5' from floor.

I would recommend drawing your design on graph paper until you get the balance of the elements you like. If you like the one pictured, then measure the size of the firebox and compare it to the size of the other pieces. I just did a simple graph overlay (not perfect as the fireplace is on a slant) and it looks like the outer layer is about 1/4 of the width of the firebox (2 boxes wide compared to just under 8 boxes wide.) So, for example, if the firebox is 32" wide the outer sides are about 8" wide. You can be more accurate by printing the picture and measuring with a ruler. Use those ratios with the size of your own firebox, and draw to scale until you get a design that pleases you.

I have 10 ft ceilings. I feel that the ideal height for the top shelf of the fireplace is between 50-54. Planning to put a big mirror or artwork above. The fireplace will be in the living room, so it's more for looks than function. I was measuring wrong, but anyway I like having it all marble because it's safer in terms of passing inspections as well as not worrying about the shelf becoming dark from smoke. I think I should keep a hearth 4-6" off the floor. My bottom layer will be bigger than the corresponding sides. Do you think that's OK or does it need to be all the same?

My fireplace cut out opening is 42 wide by 21 1/2. There is 16" off the floor to the bottom of the cutout. Any design ideas? I need to order tomorrow :(

Can I continue the picture frame surround all around the fireplace or will it look odd? I am loosing my mind. The fireplace is in the wall.

This is the design I came up with using snow white polished marble. What scares me is that my mantle is very wide 69''. The fireplace is 42", had I known I would have went with the 36". Do you think 69 x 55.75 is OK or way off???

Superior fireplaces WRT/WCT3000 series. I unfortunately have the 42" model. Woodburning fireplace.

That's exactly what I want to do. My whole surround will be marble no wood

You are using a white marble surround for a wood burning fireplace?!? I used marble with a wood mantle & over mantle. I was undecided before we moved in if I wanted that FP to be wood burning or gas, so they ran a gas line and we just left it (it was summer, anyway.) We have a wood burning FP on our porch with a gas starter. After that first fall of enjoying the heck out of our porch FP, I was like, OMG...I will NeVER burn wood in that marble FP! Burning wood is such a mess! It is fine with, say, a big, stone FP or something, but I simply cannot imagine all of that sooty mess on pristine marble! I went and picked out some gorgeous gas logs and love flipping that bad boy on when I get a tad chilled! :) Anyway, I know I am not answering your question, but just wanted to make sure you considered what wood would do to your marble!

I have gas connected to it as well. What will it do to my marble?

Take a look at the surround & hearth of any wood burning fireplace. You will see a little or a lot of black soot. Our outside FP is white painted brick, like our house. It is IMPOSSIBLE to keep it looking pristine, wood is generally dirty, and again, the smoke & soot. Now, it doesn't really bother me OUT THERE (and we clean the firebox & hearth pretty frequently) but I can assure you I wanted no part of that dirty wood & soot anywhere near my marble! :) Marble doesn't take kindly to the type of cleansers/scrubbing I do on the outside FP. Now, maybe someone with a wood burning white marble FP will chime in and say I am nuts and their FP has no problems at all with dirt & soot...and I will stand corrected. :) But I wasn't willing to take a chance on messing up my marble. One of my friends has a slate surround...that might be a better choice for wood burning?

This is making me nervous. What are my options? I wanted it to be pretty, but functional.

I think if you go with a gas log you can have all the marble you want without the incessant dust and discoloration that burning real wood brings. I would honestly stick with that. Do you have natural gas or are you on propane?

As for actual heat - the gas log fireplaces do put out good heat. Get a blower if you need one. We had a FP with a blower in our last house and it would cook you right out of there. For this house we didn't get one as we wanted to warm the main areas (open concept) but we like our bedrooms and such cool for sleeping.

Quick google: http://howtocleanmarble.org/clean-marble-fireplace-surround/

It says smoke is corrosive to marble as well. Abick I think I'd avoid the real wood!

Soot stains on a fireplace surround are caused by poor design. The fireplace in the photo either has a flue too small for the firebox opening, inadequate throat and smoke shelf configuration, short chimney, a thick surround at the firebox head, or a tight house without a ventilation air exchanger.

Other than chimney height and air tightness a properly installed "zero-clearance" factory-built fireplace is unlikely to have a soot problem. If you are still concerned, find some nice granite; it will make a more serviceable hearth too.

To me, it boils down to what is most important to you. If having a wood burning fireplace is the most important thing, I'd use granite or slate. If the most important thing is having a pretty white marble FP, I'd use gas logs. There are some amazing looking gas logs that put out great heat. We have been super pleased with ours.

The fireplace i got is wood burning, but it has natural gas connected to it with a key in the wall. Can I purchase gas logs and just use the natural gas without ever burning wood since it seems to be such a risk to the marble surround?

I decided against the all marble mantle. Too much money and not very practical. I will do typical surround using quartzite (not man made quartz) which is easier to clean than marble and a wood mantle with shelf. Should I leave some of the black metal (top and bottom of opening) visible or cover it all with the quartzite right to the opening?