Single solid wood plank across door way entrance - Expansion gap?

[stoobloo]

I'm going with a 10mm expansion gap around the room, but am currently starting at the door way as I want a full plank to start as you come in to the room - mainly for strength as it will get the most hammering!

The planks will run from left to right of the door way. I've cut the door jamb/architrave so the flooring fits nicely underneath - but for it to look nice under the architrave, and door frame there will be minimal expansion gap - is this going to be a problem, or do I need to cut away more around the bottom of the door jamb/architrave?

 

[Notch7]

If this is a floating floor, I would say you want the same gap

 

[big-all]

in general you would start with a full plank assuming first room you will have no offcuts
now in general the wall and door face will be flush so the edge off the door plank will have to extend around 12mm with tongues removed under the door to sit under the threshold strip hidden under the door' now this requires around 30mm including tongues to be removed from all the planks on that wall this can help with deviations as you have something to trim
always always have full expansion if you can to avoid tenting

i wouldn't worry about narrow bits too much as you have a threashold bar elevated perhaps 6mm 'a fully supported floor under the flooring and say a 10"/250mm foot length to support your weight so minimum point loading