We are building raised flower beds around our home using cinder blocks (and mortar). The footings have to be below the frost line, which is 42 inches. The contractor wants to dig down 27 inches and then every 4 feet drill holes down to a total depth of 48 inches. He would then pour the concrete so it filled the holes and then be leveled off so there would be a flat surface 19 inches below grade He would then place the concrete blocks on this flat surface and building up. I have never heard of this method of laying footings. Will it work or will the frost break apart the concrete between the holes that go down 48".

This appears to be a very complicated expensive way of making raised flower beds. From a gardener's point of view.

You're kidding I hope or very wealthy. Pressure treated 4x 6 or 6x6 would be a lot easier and much cheaper. If they frost heave just reset them.There is no Arsenic in PT wood anymore.

I would see no specific code reasons for a foundation, but this would not stop the settling of the areas between the "holes" and to my opinion cause it to be more chance of uneven. A trencher can easily dig down that deep very fast and easy if you want a real foundation.

But as the others, I have never heard of such things for a flower bed and assumed you were joking about this, but if serious, there is my opinion

I didn't tell give all the details. This is part of a larger project, which we are doing for landscaping purposes. We are replacing a sidewalk and two sets of steps at the same time. And these "flower beds" are tying these things together. We are putting veneer natural stone over the face of the cinder blocks. This project is more for appearance purposes than having a place to put flowers. Yea, its expensive, but we're sick of the way the house looks. I understand we need to have footings below the first line to prevent frost upheaval and the walls shifting and breaking.