I bought this house last year. It was built in 2004. We started noticing popping noises from the walls and cealing. Some areas, when we walk, it creates popping noises from the walls too. Particularly, our master bathroom area. The builder called one contractor and he tried to fix the problem by fixing the floor on the 2nd floor master bedroom and master bathroom area. The problem did not get resolved. Second contractor found loose cealing and he tried to fix the cealing with hundreds of screws. It helped a little however we started noticing this popping noise again. It is more in the morning than later. When I go to master bath in the morning... I here cracking sounds from the walls.At nighttime, without any body walking... we hear this popping sounds too. Sometimes, I am sitting in familyroom and I hear popping/cracking sound from the cealing.(our master bedroom is on top of the familyroom). We have same problems with other rooms too. However it is less appearent... may be those rooms are little smaller than master bedroom. Any suggestions... I just called the builder again... we are in California