To have the outer length of the house aligned with the 0.0 mark on the grid so that you do not have to keep in mind that part of the length is outside of 0.0.

Maybe you should think about that. The position of every object for a house is in relation to each other, not to a position on the grid. It's just a psychological quirk that we as humans feel more 'comfortable' starting at a known point. It really doesn't matter where you start the first wall of your house. It will be the only object starting at 0.0 and the rest is related to that wall, not to the starting point. You could start your first wall at 122.7,-20.3 and it would change nothing.

If you really want the first wall to start at 0,0 just move it after drawing: half of the thickness to the right, and half of the thickness down. That will position the top left corner at 0,0. From there you work from that first wall and probably not look at 0,0 again.

The only good reason I can think of where positioning the first wall at a specific location is beneficial, is if you have a complex base plan and use the grid coordinates for placing other elements. In that case it is probably more logical to place the center of the wall at 0,0, not a corner.