In general, all tile and plank layout should be done to maximize the size of the pieces along both the starting wall and the finish wall. in general, unless you have at least 3/4 of a unit at the end wall, you wan to cut both the starting and ending rows to have a more balanced appearance. (Even with 3/4 of a full plank, you may still want to divide the difference for a more symmetrical appearance).
Assuming fairly square walls, you figure out the size of the edge strips as follows:
- Compute how many full units fit across the room.
- Compute the extra width beyond the full units.
- Add that to the width of a full unit.
- Divide by 2. This is the width of your starting row and finishing row. (Your full rows
will be one less than the maximum total you first computed.)
Examples:
Room is 10'2" feet wide and tiles/planks are 1 foot wide:
1. Maximum full units is 10
2. Extra width is 2"
3. Extra plus one unit is 1'2" (14")
4. Half of that is 7". (Starting and ending rows are 7" each, 9 full units in between)
and
Room is 10'10" wide and tiles/planks are 1 foot wide:
1. Maximum full units is 10
2. Extra width is 10"
3. Extra plus one unit is 1'10" (22")
4. Half of that is 11". (Starting and ending rows are 11" each, 9 full units in between.)
In general, flooring will be finished with a molding over a gap left around the perimeter (usually 1/4" to 3/8" depending on the flooring material). This gap is needed to accommodate shifting of the flooring materials due to seasonal shrinking and swelling.
The door transition needs to be adjusted to reflect the door saddle or other capping mechanism. A gap is needed at that transition as well as the wall edges. You could use either A or B if the door transition cover will give at least a 1/2" cover of the edge.
There are two ways to install flooring in areas of different heights. The cheapest and easiest method is to install transition pieces or thresholds between the areas of different heights. These transitions are available in different matching shapes and heights for most laminates. Common use is to join carpeted, tiled or other floors, to new flooring height.
The second method is to install new sub=flooring of a correct thickness over lower floors to make all the floors match in height. This is a bit more expensive and will add a day or so to your labor costs, and possibility require some extra trim work. Having all the floors at the same level will make for a nicer looking install, especially between larger rooms with wider passages.
Best Answer
Guessing that the luan subflooring is only 1/4" thick I would strongly suggest that you remove it. Since the existing carpet squares are glued down to it I suspect it would be way more work trying to remove all the glue and prep its surface to a suitable condition for the laminate flooring.
If you tried to leave the luan subflooring any type of transition that you attempted to use would most likely be noticable to some people to say the least. In addition the transion zone would place stress on the snap together joints of the flooring causing them to not stay nicely closed.
I am not a big fan of laminate flooring in the first place but suggest that it wants to be laid down on a surface that is flat and continuous.