We have just lifted the floor carpet in our hallway (bungalow) to have a look at the floorboards. The floorboards are floating I believe. There was straight diagonal lump under the carpet and I assumed someone had nailed on a board to strengthen the horizontal running boards once of which was very squidgy. I have now revealed, 1 rotten floor board, maybe woodworm as I can see the tiny holes, just in the this board and its gone all soft, but diagonally is a strip of concrete. What is this. The boards are cut around the concrete and I dont know where it stops and starts as it dissapears under the wall to our lounge and the otherside continues too under the door frame. Is this a strengthening mechanism for the floor of the house or have I uncovered something else. We were hoping to strip and stain the floorboards in the hallway but maybe not now.