I jus completed my renovation. However, i discovered that my kichen floor trap is choked with cement. I verifed by putting my hand into the floor trap and i can feel solidified stones inside. Water is still able to flow, but very very slowly. Is it common for contractor to dump cement waste into the floor trap? I tried to remove some of them, but as i reach lower, i feel the cement has solidified into one big stone and i can't remove it. Is there any effective way to solve this problem? (dissolve the cement w/o hurting the pipe?) I am getting the contractor to come back to solve this problem. But i wonder what can he do to effectively remove all the solidified cement stuck in the trap below. TO make things worst, the floor trap is consealed under my kitchen cabinet and it is hard to reach. Last night i called a plumber to come n try to clear it. He used an electric auger snake but failed. He said the cement has solidified until very solid hard and the only way is to remove and change the entire pipe. Is it true? anybody got such experience?