We have a 1907 balloon construction house. We removed some structural walls and installing support beams. This was about three years ago.

We installed new hardwood flooring over the old fir sub flooring on the upper level, and had the maple hardwood refinished on the main floor. This was about two years ago.

For the past year or more I have noticed the hardwood on the main floor shifting... some strips have pronounced space in between the 1.5" strips, while other strips seem compressed together. There are also dips and waves I can feel when I slide my socked foot over the smooth flooring. All this is in-line to where the beam was installed.

On the upper floor, around the same area (beam installed as well replacing a structural wall that was removed) the new hardwood flooring is starting to squeek and move a bit when I walk over it.

I'm concerned, but the guy who installed the beam said if the house was shifting the drywall would be cracking.

Is this most likely the result of the beams having been installed? Should we be contacting a structural engineer? I'm worried that it will cost us a lot of money to hire an engineer, and we already put a lot of money into the house and can't afford to put thousands more out, but at the same time I don't want our house to fall down!

Has anyone else here experienced anything similar? Care to share your experiences?