Great tip on squaring a room! By starting in the center and measuring off a center/squared line you are able to check all walls off of just the 2 , 90° lines. The object of this video was to show how to square a room....as was demonstrated in our Virtual Workshop program on The Ins and Outs of Layout. In that Virtual Workshop we actually show both ways ( the way you described and the way I demonstrated it in the video) of checking your room for squareness before starting floor tile, or laying out the float strips ( as I was showing in the video) so that the walls are square and parallel to each other. In my experience of mostly commercial tile installation, I find it easier to establish a reference line off my longest wall and then check the others off that line , and square off that main line, instead of establishing a true center/square line and then checking all walls off of it...then going back and snapping the line I will set my strips off of...I feel it saves me a bit of time . I realize I am taking a chance that I may have to adjust my original line , however that doesn't happen too often. Usually these days I use a laser square, which makes this process so much easier. However we feel that tilesetters should know how to do it using the 3-4-5 method, in case your laser breaks or you are in a very large area that makes a laser less than optimal. The Ins and Outs of Layout Virtual Workshop, can be on the NTCA KZfaq channel. Thanks for your comment 👍

Here is the link to the workshop video we mentioned: kzfaq.info/get/bejne/gcBheLSi0drOZ2w.html