We are installing bamboo flooring on the main level now. The old hardwood is just too far gone, plus with the holes from when we removed a closet and adjusted the opening for the new back door, there are some awkward areas with no wood at all. There's no way we'd be able to match it and make it look okay. The problems of the old floors are also compounded by uneven settling of the house over the last 90-some years. There are humps and dips that drive us nuts. If you drop a marble by the front door, you can watch it roll down the hall, then it will turn and roll all the way into the dining room before falling into a hole from a broken floorboard.
Installing new flooring over the old gives us the advantage of being able to re-level it all, and have consistent flooring throughout the foyer, kitchen, dining room and living room. We chose a carbonized bamboo that's darker than the natural stuff you see in modern-style homes. The bamboo is steamed to a specific point until it begins to release its sugar, turning it a caramel color that goes through the whole board. Beneficial if/when it gets dinged because the color won't chip or flake off like with stained wood.
Here's Pop spacing out shims in the foyer to level out the hump that runs down the middle of the floor. These are just nailed down to the old floor.
In this view you can really see the difference in elevation.
After the shims are down, Pop and B nailed down a thin sheet of 1/4 inch plywood to help raise the foyer floor up to meet the old kitchen tile. They began laying the bamboo in the transition from the kitchen and foyer, so both areas would be perfectly square and wouldn't have an awkward joint.
It took three very long days to get the foyer, kitchen and dining room done. A tip when working with bamboo flooring: make sure you have a brand new blade in the chop saw. This stuff is TOUGH. By the end of the last day, the brand new blade we bought was shredding the boards.
We are waiting for a decorative trim to come in at the lumber store to do the living room. I think we'll need another new blade when we get started again and get the flooring finished!