Thank you for your help. Here are the after pictures excluding decorative accents. Wall paint BM Palladian Blue, floor tile 12"x3" grey marble polished porcelain, accent wall tile 24"x12" white marble polished porcelain with white marble stone pencil border.

I heard back from Schluter. Here's my question and their answer: Question: Can the uncoupling membrane be installed directly over existing ceramic tile? This is a basement - the tile is installed over the concrete subfloor. Tile is in good shape - just ugly. We don't want to remove it. So if the membrane can be installed over top, what type of thinset should we use to bond the membrane to the existing tile? Answer: If the following requirements are met, we expect this type of installation to be successful. However, given the wide range of potential existing conditions, this application is not covered by a specific detail in the Schluter-DITRA Installation Handbook and is therefore not covered under warranty. In principle, DITRA can be installed over existing tile. In general, the following minimum requirements must be met for a successful installation. The substructure must be adequate, per the DITRA Installation Handbook (e.g., joist spacing, plywood thickness, etc). The existing tile must be well bonded; any loose tile must be removed. The tile must be cleaned before the DITRA installation to remove any bond breakers. The DITRA can be installed in a similar fashion to what is called out in detail D-V-T in the DITRA Installation Handbook. (I looked this up, and it's referring to installing over vinyl.) Option 1. Use a rapid-setting modified thin-set mortar suitable for bonding to existing tile to install the DITRA Option 2. Skim coat the tile with a modified thin-set mortar or suitable cement-based embossing leveler, allow it to dry, and install the DITRA with unmodified thin-set mortar For further details please see attached Ditra installation Handbook

Yes, it’s called quarry tile, and the application is called broken quarry tile. As Ripped Jeans said, take pieces with you to try to match. I’ve seen it at HD, but it was darker red than yours. A good tile place should be able to help you, or you can look online for any that someone might be selling after a reno. It was popular in the ‘50s, too. I love it. Glad you’re keeping it. :) This mixed color one is circa ‘50s (just showing for fun): ETA: One I saw, but cannot vouch for this seller ... just posting as an example: https://www.etsy.com/listing/869748968/ceramic-tile-quarry-tile-6x6-red-beige?ga_order=most_relevant&ga_search_type=all&ga_view_type=gallery&ga_search_query=quarry+tile&ref=sr_gallery-1-1&from_market_listing_grid_organic=1&frs=1&col=1

@Millworkman Thanks. That thought about adding another layer (and maybe getting less heat) did cross my mind. I'm not too concerned about it though as we cook a lot and are generally hot natured people (we keep our heat pretty low in the winter). Plus the kitchen is fairly small (less than 200 square feet and that includes a broom closet and small walk in pantry). I'm sure the proper way to do it would be to rip it all out but I worry about damaging the heating system. Is a little heat better than the risk of no heat? Ha!