This is a very common problem with Blockmould process. Customers have more moisture inside the blocks than the outer layer. This problem is coming mainly the steam flow and program set up on the machine. Akkaya latest blockmoulds are Frame Effect Free! You are welcome to see a recent blockmould from Akkaya in Venice /Italy. We will be glad to make a presentation in our customer for you. Raw material Eni-Versalis AM 7000 AE density 10g/l.