Need a solution for a hole in the floorboard

[cowprint]

One of the floorboards in my son's bedroom has a fist-sized hole. It's in a high-traffic area and can be felt through the carpet.. We've recently taken up the carpets, and I took this photo. Before we put the new carpets down we'd like to sort it out. Can it just be filled with something (if so, what?) or would we need to replace the whole board?

What about a thin metal plate screwed down, a little larger than the hole?

You might be able to cut around the hole and infill with wood. If you don’t want to go to this effort, put a metal plate over it. To make if totally even, you can put hardboard over the whole lot then a decent underlay.

It's a floorboard. Take it up and screw down a new one.

Looks like it has been butchered by a plumber with an axe.

Measure it. It's probably four inch x three quarters square edge.

But 100mm x 18mm will be near enough.

When you look at your measure you will see why.

Replace the whole board, not just the broken bit.

Buy two of these
www.screwfix.com/p/roughneck-electricians-bolster-3-x-11/63668
And lever it up bit by bit along its length

New board or put some expanding foam in. It will swell up then when it's dry just cut it flush with the floorboards using a Stanley knife.