If so clear any old putty and refill the gap with a white putty mix (I know that they say modern paints ect) I normally add a thumbnail of grease to a ball of putty about the size of a tennis ball, this will make it easier to push into the gap.
After you have cleaned the excess away paint it over with primer (immediately) to prevent any drying. As the planks then expand the putty will still be soft enough to push out.
Not a difficult job but a real pain to do! You will find muscles in your hands you didn't know you had.
Good luck Tom
-------------------- I wish I'd been born rich instead of good looking ?