Hi - my family moved into a house ~1.5 yrs ago. It has very beautiful looking brazilian hardwood floors throughout that were installed ~7 years previously. When we examined the house the floors were solid, didn't squeak, didn't notice any issues (this was in summer). When we acquired the house, overtime, we've noticed the floor boards are squeaking more and more. Further evaluation showed some settling in the walls (apparently when the house was built), and some slope in the floors.

We had a company come in to put supporting beams in the foundation. This helped eliminate bounce and reduce some squeak/crunching. However, not all. Further, other areas continue to squeak/crunch. Basically every step there is a "crunch". We find in the winter time this is really bad.

Some basic questions on this:

1) Is it likely the settling, slope in the floor is the main culprit? I do notice some areas where the floor isn't "flat", and there's movement when you step on the board. Note the boards themselves are smooth, no boards sticking up. The finish is very nice.

2) I assume humidity / cold is playing a part here. Anything we can do in winter to alleviate the noise? The temperature in some rooms goes from 60F -> 70F depending if the heater is on.

3) I've noticed some boards themselves aren't perfectly flat (perhaps expected). However, a paranoia item is could we be using incorrect floor cleaner and that is damaging the floor? it could explain how overtime the noise is getting worse... perhaps the floor is absorbing the cleaner? Afaik we are using a high-end cleaner for wood floors, and wiping it off immediately after application.

Any other advice or thoughts folks have would be greatly appreciated. I hate the feeling that we may be damaging the wood and its getting worse year-by-year.

Thanks