I've dealt with plasterboard before and I'm quite sure this isn't, it was much harder to drill through? It seems like plaster. It's just the small void that I'm confused about?
Ok I'm new to the forum but have used it for reference so many time. So here's my first question.
I'm trying to install a Venetian blind to the inside of my kitchen window having just moved.
I've always installed my own blinds either to a baton already installed or into Woden window...