I hired someone to create a hole in the concrete block wall for a window. However instead of using a saw he used a sledge hammer and created a larger hole then necessary with a very uneven edge.
Now I need to patch the concrete block with concrete cement to the desired rough-in opening for the window. I am using two pieces of wood on each side to help me fill in the cement along a nice even edge. However along the top edge, I need to fill in the block wall holes with solid concrete but it's upside down so how can I do it? I imagine anything I put up will fall down right the way. Any tricks?
Thanks,
MC