Wood works, always. It adjusts itself to the moist-content in your home: expands when there is an increase and shrinks when there is an decrease. That's the reason why we recommend to leave a sufficiently wide expansion gap around the whole perimeter of your wooden floor - it gives your floor 'room' to move - and it will, no matter which installation method you use.
Cupping of a floor happens when the floor absorbs so much moist it fills its expansion gap completely - or is 'stuck' in one spot due to very heavy furniture, faulty installation method - and has to go somewhere - up.
Excessive circumstances can happen to everyone: a leak, a flood etc, but those are temporary circumstances. 9 times out of 10 it's a case of 'removing' the cause and the cupped floor will settle again to its normal state.
However, we frequently get the question: "Should I sand down a cupped floor?"
The picture underneath explains what will happen then (click on the picture to see its full size).
It will 'look' fine temporarily, but as soon as the normal house climate is restored the floor will 'crown' - forever!
Best solution to resolve cupped floors: find the cause first e.g. leak, heavy downpour causing more moist than normal in the void beneath the wood floor, new appliance in the room or connecting area that causes more moist than normal - think of a tumble dryer, dish-washer etc - sudden and hefty increase in air humidity outside due to the seasons.
Some of the causes you can resolve, some you can't - or not easy or quickly. But if you don't know what causes the cupping then you can keep having the same problem over and over again.
To reduce the strain in your wood floor that is causing the cupping-effect: remove beading or skirting along one side of the room that runs parallel with the direction the floorboards are installed - wood hardly expands lengthways - and saw or chisel off a small strip of the last row. You'll be amazed how little you need to cut off this way for the floor to 'settle into place again - so start 'tiny', you can always redo the procedure.
A circular plunge-saw comes in very handy in these cases - quick and simple.