What is the best way to fill this hole in facia board?

[carpet_the_walls]

 

[footprints]

Same as repairing plasterboard, cut a bit of batten to extend about 2 inches either side of the hole, put a hole in the middle with string attached slip the timber in and use the string to pull back hard against the facia then screw through the board (pre drill and counter bore the holes) to pull the timber back firmly against the back of the facia, fill the hole with a bit of scrap wood glued to the timber and then fill, sand, paint etc

 

[carpet_the_walls]

Same as repairing plasterboard, cut a bit of batten to extend about 2 inches either side of the hole, put a hole in the middle with string attached slip the timber in and use the string to pull back hard against the facia then screw through the board (pre drill and counter bore the holes) to pull the timber back firmly against the back of the facia, fill the hole with a bit of scrap wood glued to the timber and then fill, sand, paint etc

Thanks for this, will any piece of wood approximately the right size be suitable for plugging the gap? It is an odd shape.

 

[footprints]

Any bit of wood just a rough shape, you will be filling around it, the wood is just to save filler and bulk it up.

 

[Wayners]

Cut rectangle wood. Lay over hole and draw around. Stanley knife the pencil line. Drill holes and cut out tidy or easier to use multi tool to cut out.
2 pack wood filler and push cut wood in hole. sand and fill.

Could use a mix of PVA and wood dust from drilling holes to make a glue paste Vs 2 pack wood filler..

 

[noseall]

Thanks for this, will any piece of wood

Some ply might be better as a slender piece of timber may split. Use 40mm 4's (screws) or slimmer. Be aware of rafter ends blocking, you may have to orientate vertical.