Some of you may wonder why you should use a chalk line as the reference and just not the wall down the lower side itself. The issue is houses usually aren't square, but the flooring is.
Also above, when you chalk the line through the doorway. It is not a bad idea to check the measurement from this line up to the wall into the living room to check it's squareness to the project. The primary reference line through the doorway can be fudged up or down on one side or the other to make how the floor breaks on the living room wall look right. Believe it or not, a person can easily pick up the boards being off by a 1/2" squareness from one end of the wall to the other.
The walls you should worry about are INTERIOR long walls, not the exterior walls. People look down interior walls, but rarely do they look down exterior walls. The longer the wall, the more variation in plank width can be picked up.
What we are trying to do is make it so when you walk into the front door and look through the foyer door into the kitchen, the whole job is straight as an arrow. We also want this long run to have the planks ripped the same width all the way down the wall going up against the living room wall, which makes all the rips the same width inside the living room itself on that wall.
Depending on how your foyer door breaks with the flooring plank width, the start of the project may need to be with ripped boards along the lower wall as well. We don't care what the lower wall looks like, we want the doorway to look good (and be easy too)
Like I stated above, most houses are out of square to a degree. The non-square can be compensated for by using a chalk line as a reference point instead of the walls themselves.
After this, you'll walk into your friend's homes and be critiquing their flooring installations....lol
Alan
I've not been posting in here enough, making up for it :-)
Q