Curious to know if a time or depth requirement is used (e.g. plow parking lots and shovel walkways and stairs every 3 inches or every 2 hours etc.).

Fix the source first or your just putting a bandaid on the damage and its just going to damage new stuff.If this is a long run gutter, looking at increasing the downspout size to 6 inch vs the 4 inch that appears to be in the picture.

Louis climate well, but brick has an R value per inch of roughly 0.20 / inch. 

For two inches of thickness, you're probably looking at 6 pounds per sq ft as a very rough rule of thumb.

They're only a little more than a 16th of an inch thick.

Tore out some walls, finished out a basement, and replaced every inch of the home.

As the old saying goes “if you give them a inch, they will take a mile.”

Then, I was told that 6 months ago that someone had visited the site, and discovered there was at least a couple inches of standing water in the crawl space. 

Prophesy such returns.Put your faith in the two inches of humusthat will build under the treesevery thousand years.Listen to carrion – put your earclose, and hear the faint chatteringof the songs that are to come.Expect the end of the world.

We did a full interior gut to the studs renovation, full exterior renovation, dug out the basement and gained about 7 inches, fully finished the basement, added a bathroom in basement, and added a 4th bedroom on second floor.