John Cooper and Wayne Starsmore. Took in 2 bags of sand and a small bag of cement. To clarify, a bag of sand taken in is half a builder’s bag of sand (although I think Adrian adds an extra scoop!) and a small bag of cement is a 12.5kg bag (a normal bag is a full builder’s bag). Two mixes of cement were taken to the bottom. One mix is 1 of the bags of sand made up to a 4 to 1 ratio with Portland cement. More rocks were dug out of the floor and cemented into the walls, first by Wayne and then by John. 2½ hours.