When scripting, making new bricks and positioning them in a certain vector. The brick will either (if there is another brick in that position) will just move up over the position you wanted.
Is there a scripting method to preventing shifting positions when you make bricks.
I don't completely understand your question, but I take that if you create a new brick and it intersects with another brick it will "spawn" on top of that brick.
You can fix this by using the following code:
part.CFrame = CFrame.new(Position)
This Position is just where you intended it to be (vector). This CFrame constructor (creator) makes a CFrame for you on that Position. It basically converts a vector to a CFrame.