Seal 30mm gap under door?

Pull the door off and pin a strip of timber to it?

Ain't gonna matter how pretty it is too much that far down.

You can get concealed retractable ones, but 30mm is pretty big, almost new door territory.

Easiest nearly no-saw opinion might be:

• two 18x18mm dressed pine squares
• one small pot of Selleys No More Cracks Doors & Trims
• nail it, fill it, sand it, paint it

Or you find a friend with a table saw/circular saw and rip 24mm dressed pine down to the door width

A hairline crack will likely show but you'll have to squint to see it

Or live with it. My house is like this everywhere but I have 100 year old doors and matching the Rimu stain will be very hard

New door leaf? Around $60 then a bit of labour to install hinges handle and paint etc

Just get a new door. It will look the best, they are not that expensive and it is a fun DIY project.

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