You cannot restore every wood floor by simply refinishing it. If your wood floor has become warped or if several of the planks have become damaged, you will typically need to replace the entire floor, as finishing will only brighten an already-damaged surface. On really old floors, you may see the tongue where the boards come together, or your boards may lack adequate thickness. Floors like this are definite candidates for replacement, as refinishing is purely cosmetic. Denver Hardwood Floor Install
Cupped floors, also called washboarding, develops gradually across the width of the wood strip where the edges of the hardwood planks raise up and the center of the board sinks down. The cause of cupped floors is a moisture imbalance where there is more water on the bottom side of the wood plank than on the top. The only cure is to balance the humidity levels in your home, and to give the surface time to return back to normal. After the floor has stabilized, you can have a professional sand it flat and re-finish it to perfection. Hardwood Floors
To fix a buckled floorboard, you need to be able to access the floor from below. The way to tackle this problem is to put weight on the buckled area from above — a cement block works well. Then install a 1 1/4-inch screw in the buckled flooring from below. Allow the screw to penetrate only halfway into the flooring, or it may come up through the finished surface. Driving the screw through the subfloor and into the flooring pulls the flooring down against the subfloor and gets rid of the buckled spot. Denver Hardwood Floor Install
Eliminate any problem spots to make the subfloor level. Sand minor humps down with a hand-held or orbital sander to make the subfloor level. To fill any dips or low spots, use a leveling compound (also known as floor patch). Mix up the compound according to package directions, fill in the dips, then pull your straight piece of lumber back and forth over the spot to flatten and level it with the rest of the subfloor. Denver Hardwood Floors
Awesome explanation! When I say heat pump to people, it's amazing how often their eyes glaze over...even though most of them have had refrigerators and air-conditioners their whole lives and have never asked themselves how they work. Same principle! Compressor and expansion valve (and the heat-holding capacity of a phase change; another confusing one for people). thanks for helping educate!
Engineered wood flooring has other benefits beyond dimensional stability and universal use. Patented installation systems allow for faster installation and easy replacement of boards. Engineered wood also allows for a floating installation where the planks are not adhered to the subfloor or to each other, further increasing ease of repair and reducing installation time. Engineered flooring is also suitable for underfloor and radiant heating systems. Hardwood Floors
Another common hardwood floor malady is the development of gaps between planks. The most common causes of gaps between the boards is Mother Nature. Wood shrinks as it dries out, and it expands when it gets wet and humid. That regular expansion and contraction over time is the most common cause of gaps, and is the main reason why most gaps are seasonal in nature. Perhaps your best plan of action is to exercise patience. Denver Hardwood Floor Install
There are some characteristics that are common to each category: solid wood is more frequently site-finished, is always in a plank format, is generally thicker than engineered wood, and is usually installed by nailing. Engineered wood is more frequently pre-finished, has bevelled edges, is very rarely site-finished, and is installed with glue or as a floating installation. 
To fix a buckled floorboard, you need to be able to access the floor from below. The way to tackle this problem is to put weight on the buckled area from above — a cement block works well. Then install a 1 1/4-inch screw in the buckled flooring from below. Allow the screw to penetrate only halfway into the flooring, or it may come up through the finished surface. Driving the screw through the subfloor and into the flooring pulls the flooring down against the subfloor and gets rid of the buckled spot.
Refinishing a floor takes a lot of time. You’ll need to remove all of the furniture from the room. The wood needs to be sanded bare. If you need to make a structural or cosmetic repair, you must do so before staining and coating. During the week that all of this is going on, nothing else can happen in that room. Dogs cannot walk through and sniff everything, children cannot bounce their balls, dust is everywhere, and the smell is enough to kill you. Well not really, but you get the idea. All of this time and trouble is reason enough for some homeowners to prefer having the old floor ripped out to put in something fresh and new. Hardwood Floors