Good plan but there's another party who might just raise an objection or two. Having said that, the MTS would offer better Saturday night viewing that X Factor!
I meant thick* My father built/renovated properties throughout my youth. Moistures ebbs into building from the surrounding. Removing it from rising up through floors is the most important he always argued. Basically you dig down but not under the walls foundations a good few inches. Lay down a half-inch of sand to help bed the concrete floor, place ontop of the sand a thick plastic waterproof membrane. Which must lap up the inside of the walls to say skirting board height. Back fill with a good 3 inches deep of concrete & once tempered or tapped with a wooden stick to remove air bubbles. You add a grip pattern or better still. Follow what narrow boat builders do. Leave the surface smooth, add a glue & paint liquid mix. Paint it over flooring once tacky, sprinkle course sand over. Let it dry & repeat the process for a few layers. This provides a grippy surface with the ability to wear down & also be totally removed if required.
