We just bought a house in southern Spain and we decided to turn the upstairs guest room into a large bathroom.We started by digging up the tiles. The tiles are about 400mm squares and when we lifted them up, we found these strange concrete squares underneath. The tiles we're putting down look like long pieces of wood, so I'm worried about the tiles having no support in the channels between the concrete "squares". I'm sort of glad that the channels are there for plumbing: it's going to be easier to run supply and waste lines in those channels; but how do I fill them in to prepare the floor for tiling?Also because it's a wet room I probably need an underlay, right? via /r/DIY https://ift.tt/2Ml0fWP
