I appreciated Rob Arnold's mathematical approach to making ends meet on a very difficult deck to design and lay out ("Pool Decks," March/April 2011). However, I was surprised by his approach to finding the line of the footings. It called for pulling a string from one side of a pool to the other and then plumbing down. I suggest an alternative method, using two tape measures. It's more precise, takes less time, and can be done by one person.

First, locate point A (see illustration below), which is any corner of the pool. Imagine an equilateral triangle whose corners are points C, B, and D. Determine the length of the triangle sides by measuring from C to D (the corners at the top of the pool adjacent to point A), then lock each tape measure at that measurement.

Working on the ground, place the end of one tape measure at point C. Place the end of the other tape measure at point D. Intersect the other ends of the tape measures at point B. The footings will be along line AB. This method works no matter what number of sides the pool has.

For even greater speed, I tack two 2x4 legs to a crosspiece to make a V-shaped jig that mirrors C-B-D. With this jig, I'll mark the footing line at one point and then rotate the jig around the rest of the pool. This is a great time saver that is shockingly accurate.

David Balzer is a deck builder in Rockford, Ill.