AW-02Work out what's behind the lath and plaster on each sideLath and plaster is thin wood strips nailed to timber, then covered in plaster, so behind it you'll find either solid brick or blockwork (typical on a chimney breast) or a timber stud partition (typical on a dividing wall). Run a stud detector or magnet over each wall and tap along it: a dead, solid sound means masonry, a lighter, hollow sound at roughly 400-600mm centres means timber studs. Drill a small 3mm test hole in an unseen spot; timber dust means a stud, a dull stop after 20-25mm means masonry behind the plaster. Metal stud framing doesn't apply here, lath and plaster predates metal studs, so if a detector picks up steel it's more likely a later plasterboard repair patch than the original wall.