Fluctuating levels of humidity cause the floorboards to swell or shrink slightly. Luckily, it is easy to fix any gaps that open up between the boards.
If a small gap has opened up between the ends of two boards, there is no need to panic. This is fairly easy to fix and the floor will look like new again.
Examine the gap carefully and try to work out which of the boards has moved. This is the side you should work on to knock the boards back into the correct position.
Carefully remove the skirting board using a hammer and chisel. Try not to damage the wallpaper or paint on the wall. Then use a flat crowbar to knock the row of boards where the gap is back into place and close the gap. If the gap is on the other side of the room, making it difficult to see if the board moves when you knock it, you can draw a pencil line across the board and the one next to it. This way you can see if the lines on the two boards move in relation to each other.
When you are finished, all you have to do is glue the skirting board back into place and your floor will be as good as new again.