not to ruin your day but dark wood... has new roofs and beams and decorative items. Your walls, floors, doors, and most everything will not change. There is a new door but its ginormous and won't replace normal interior viking tall doors, it replaces the 'gate'.
so apart from re-roofing, 95% of your house is most likely to remain untouched (though the % will be higher if you have an epic roof on a 1 story home)

moving from stone to marble is another story. Not only do you have to replace each block, but the blocks are not 1-to-1 replacements in most cases. This is a heroic effort, and basically either do-over or stone by stone it slowly.

here, the roof, wood poles, and arch pieces on the door are dark wood. The door is the standard 'gate', the walls are standard wood, etc. I think the bird decoration is dark wood, while the dragon is normal, and so on.
https://steamcommunity.com/sharedfiles/filedetails/?id=2924987564