I have been asked a question to which I have no direct answer. When someone I know was drilling a hole through an internal wall, more precisely above the doorway between hall and lounge, he hit a solid. The drill is an 8mm masonry drill. It turned out the material is a lump of bonding plaster, so far as he can tell and from the description and a photo I concur. He drilled on but at just over 5cm in he hit a solid of some other material through/into which the masonry drill will not pass. This is within a plasterboard/wooden studs/plasterboard hollow wall, modern construction perhaps 15 years old, between the top of the doorway and the ceiling.
He asked what I thought this was for, I could only guess that whatever this is it is in fact stuff that was literally tipped/disposed of into the void and there was no design purpose involved. I think the solid now in the way is perhaps a piece of wood. Does anyone have a more enlightened view/guess on this ? For info, the house is in Ireland/Eire - I have never been there and have only seen pictures of it.
The total thickness is 15cm and the hole he is drilling is about one third of the total height of the panel up above the door (15cm ?) - i.e. above the architrave of the doorway. This makes me assume he is pst all normal wooden members and should be in a void completely between the two plasterboard leaves. He actually tried in several locations as he kept hitting the bonding lump (still always above the doorway). His intention is for the hole to be where he has now drilled as far as 5cm+. In the absence of advice to the contrary as to some mysterious purpose for this stuff, I was about to advise him to try a wood/steel drill but I will suggest he tries to establish what the less easy material now blocking the drill actually is if he can.