How do I attach vertical blinds to drywall with a half inch space then a concrete wall behind it. They are heavy
Here's what I would do.
Make a standoff spacer to bridge the space between the concrete and drywall surface.
Make the spacer out of a piece of small PVC tube, or better, aluminum tube, say 3/8ths or 1/2&quot; diameter at most, cut to match the distance from the concrete to the outside drywall surface.
Drill through the drywall into the concrete with a masonary drill to accept a Tapcon screw. Make sure the drilled hole is deep enough (maybe half an inch longer than the screw's reach) and work the bit in an out to clean as much dust as possible from the hole.
Enlarge the hole in the drywall to accept the spacer. Use something for a depth gauge that you can push in against the concrete and mark the drywall surface, pull it out and measure the distance, and cut the spacer to that length. Install the Tapcon through the bracket and spacer into the concrete.