I am planning on laying 200 square foot of 3/4" x 2 1/4" oak hardwood. How do I ensure the first row I lay is straight? I know of the 3-4-5 technique but I am skeptical of any wall being straight or any two walls being square. The way the room is laid out any thing less than perfect will be very noticeable. Any tips or help would be appreciated.

Use the straightest boards in the bunch for the first three rows. The same is true when you near the opposite wall. What's the difference(distance) from one wall to the other on both ends?



I've never used that when starting any strip installation. Forget about the perpendicular wall lines--it's the paralel areas that you want to square up as best as possible.

The room is 13' square. I just don't want a small variance from one end of the starting wall to the other end up "growing" by the time I finish (creating a paralellogram). In your experience how much if any does the floor rack out of square because of minute variations in the width of the hardwood? I am guessing at most a 1/4" over a 10' span. I have done a little research on installation and everyone sees to gloss over the starters. I would think it is critical to get them square - but gauging from the lack of information maybe it's not that important.

Measure the distance from each corner to the corner opposite. If the measurement is the same or very close, you're good to go. If the measurement is 1/2" or more off, then divide that difference by two to split it. That way, you are not having your last row 1/2" out; only 1/4". Snap your chalk line 3" out from your walls and set the tongue on the line and as Ken says, use long straight boards to start with.