I took some time to explain to my workers on what I wanted to be done.
One of the thing that I wanted them to do was to reduce the gap between those nesting planks and the ceiling.
If those gaps are not closed or reduce most of the time those birds would not use the affected planks.
After a short discussion the worker told me something simple.
"Pak Harry just buy about 10 wall plugs. We can use those steel band to hold the planks onto the cement roof."
I wonder what they have in mind but after buying the steel wall plugs about 1/4" diameter I saw what they did.
They drill about 3 inches hole in the ceiling and inserted the steel plug into it.
They use the steel band to attach the nesting planks to the plug.
Before anchoring the planks they use a kind of wood to push the nesting plank upward until it touches the ceiling, a kind of lever.
A very simple method and it works.
I think sometime these workers are as good as you are.
They use their experience to tackle a simple problem.
Have a look at some of the way they solved those gaps.