Jeffrey J. Kosowsky wrote:
There are several round "holes" in our stone masonry foundation
presumably from old pipes that have been subsequently removed. The
holes are about 2 inches in diameter and extend through the foundation
just below the level of the sill.

I would like to fill in these holes but was wondering what is
best/easiest?

Do I mix my own concrete? (if so, what type?)
Is there a good patching premix?
Any other suggestions?

I would not suggest concrete. The mortar and many of the stones used in
those old foundations is much softer than concrete and many of the products
used today. Mixing the hard setting concrete could damage what you already
have.

I don't have any suggestions for specific materials. Maybe someone else
will have some good suggestions.

--
Joseph E. Meehan

26 + 6 = 1 It's Irish Math