It is precisely thses hdb appointed contractors that put up such high prices after bidding high prices to ge the sand, debris clearing contract from hdb, so they need to recover their costs! Imagine you do only kitchen base, you probably use less than half of a big bag of sand costing about $50 a full bag. Add a few bags of $6 a bag of cement which your ID or wet works contractor pays, and these hdb contractor just them up only and clear the balance materials after completion and they charged you $900. It is not cheaper and your government did not subsidised your sand. Why some id dont care or keep quiet before you sign on the reno contract for such small jobs? It is because there is no hacking and their hacking contractor covers sand and haulage. So for haulage, they would have to engage their hacking company to make several trips to bring up materials, provide sand, clear debris and it cost them money, so they simply dont tell the owner first or say hdb regulations, haulage and sand must be provided by hdb appointed contractor on the notice at the lift which is a lie. And passed this $900 costs to the innocent house owners who have to pay a lot more. So go with contractors that does their own hacking and wet works with own workers to avoid these high hidden costs. If you cannot find such contractor, pm me.