Hole in window sill/floor

rf87_2

Hello
I hope someone has some advice for me
We had a leaky gutter which caused a hole in the french doors window sill (obviously left too long!) Gutter has now been fixed and hole sealed from outside so the area is all dry. Thinking to use wood filler and paint but is it too big for this? Other thing I can think of is buying a wickes window sill or mdf board and cutting to fit? 
What is the best thing to do here?

Mutton_Geoff

Presumably that is a floor, not "windowsill". I would not put MDF on the floor by an opening door. In any case, you might watch to lift that section of ply to see what's underneath it (still wet and rotting is my guess). Let it all dry out, lay a sheet of membrane (thick  black plastic) then put down new WBP (marine ply) or see if you can't match the flooring to suit what you already have, eg some timber flooring planks, perhaps at 90 degrees to existing to make a feature of the doorway in a kind of "same but different" sort of way.

knightstyle

neighbour had similar problem, they filled the hole with step repair mix and then stuck some left over laminate flooring over the whole cill. looks good still after two years.

Mutton_Geoff

knightstyle said:

neighbour had similar problem, they filled the hole with step repair mix and then stuck some left over laminate flooring over the whole cill. looks good still after two years.

May have worked hiding that issue but the screw visible in the OP's post has popped. The door frame looks like it has rot. I'd still say do the job properly and replace that £3 worth of ply if nothing else. Pause half way through the job to let the floor substrate dry out.