my dad has a brick curb between his lawn and sidewalk that needs replaced. The curb is only two courses tall. The first row runs parallel to the sidewalk, the 2nd is perpindicular to the first. The problem is the footing underneath is junked. How deep does the new footing need to be poured? A mason said 12", but that seems like a bunch for two rows of brick.
Just tore out some of the existing footing, guessing it goes back to when the house was built in 1915, and it's only about 3" thick. Obviously, it didn't hold forever, but that is a long time. Is it really going to make much difference if we dig down 10-12" vs. just replacing what was there??
The mason, who is a neighbor/friend of mine, says he'll lay on whatever, but that going at least a shovels depth on the footing is best, but the deeper the better. While I don't argue that, I do question if it's really necessary on what we are having done. Only thing this is doing is somewhat holding the earth behind it back and being decorative.
I've included a picture to help give an idea of what we are re-doing and it will be mortared joints.
The rule of thumb in my area for a footer is 3' below grade
A frost footer is 18'
That said if the brick are dry laid a 12" base of stone is fine
Do a 6" base of 2b Clean ( 3/4 ) stone with a cover. This creates a Drain area so lifting is minimized
Then a 6" base of 2a modified stone ( 2bs with Limestone quarry dust mixed in) Tamp the last 6 Inches. This acts as a floating footer.
Even though the brick lasted for many years laid in Mortar I recommended a Dry laid brick OR an Engineered stone "E. P. Henry"