I'm doing a renovation on a 3rd floor condo unit. Our approval from the condo association says that we should use flooring with an IIC of 63 or greater. We believe they were referring to the hardwood flooring. We are removing carpet and installing hardwood. But we are also removing the existing tile and installing new porcelain tile in bathrooms and kitchen. The existing tile had no type of underlay. I'm not aware of any sound problems in this building with the old tile. We've lived here for 5 years and our neighbors below say they cannot hear us.

Its considered standard practice around this building however to install an underlay material underneath new engineered hardwood flooring. But what about the tile? Does it make sense to install an underlay for the hardwood but leave the tile with just the mortar like it was with the previous tile? I'm not sure that anyone in this building has ever replaced their tile but plenty have installed hardwood. I'm not sure anyone has ever thought about the tile issue previously.

Our approval is not specific as to whether the underlay applies to the hardware, tile, or both.

Thanks!

Check with your condo for clarification.

The sub strait should be a solid product. If not, tile will move and grout will crack.

Chuck