I built a surround, mantel and overmantel using MDF, various moldings and honed travertine tiles (filled). I don't know how to post pictures, but, if you e-mail me I'd be glad to send you some. To answer your questions: You can install the travertine directly on the drywall using fortified thinset (don't buy the pre-mixed kind). Just make sure the drywall is well anchored, I drove some extra drywall screws into the studs before installing the travertine. I didn't seal my tiles, but, the honed finish is smoother than what you have. The reason to seal before grouting is that the sealant acts as a grout release and makes it easier to clean the grout from the tiles. With rough tiles I've found it helps to keep a water spray bottle handy which you can use to flush out any grout that gets in the holes before it sets. 1/8" spacing is good, however, if your tiles have rough edges you may have to go to 3/16". On the hearth you need plywood for strength and then you should put down some wonderboard or hardiboard. This is because code usually requires at least 1" of non-combustible material on the hearth (check your local code to be sure what the requirement is). You meet the requirement by calculating the thickness of your tile plus the thickness of the thinset (1/8' - 1/4") plus the thickness of the cement board. You should err on the high side. Hearths can get pretty hot, so the thicker the non-combustible layer the better (it acts like an insulator). Also remember to check your local code on the required clearances from the firebox opnening to the mantel and surround. In most jurisdictions this is 12" (for non-combustible materials). I used some corbels that are closer but I bought some made out of molded stone that are non-combustible.

I just assumed it was required to have tile in front of the fireplace until my floor guy asked what I wanted in front of the fireplace. He thought the wood would look better. I started asking around and couldn't find anything that said I was required to have tile in front. I still thought wood seemed odd until I saw a picture of RTWilliams fireplace and it changed my mind. I ended up going with wood and I love it! RTWilliams fireplace my fireplace

Histokitch said the pattern is as follows: It's called a raking stretcher bond in bricklaying. Running bond is the name of the traditional subway tile look. In raking stretcher bond, each brick overlaps the one below (or above) by 1/4. It makes sense that Bill knows it as a 3/4 brick joint, which is an apt description. Malhgold - Will do!! SW - I will definitely check pricing through Heath directly, and through the Ann Sacks dealer in Vancouver. I live in Canada which makes things trickier.

When you are talking about heat-resistant, period tile, soapstone comes to mind. It's hard to find soapstone tile, but Humming Bird Soapstone is one place that advertises it: https://www.hummingbirdsoapstone.com/