Anyone who tells you they’ll deliver “perfectly square corners” in a Victorian terrace is either lying or about to ruin your skirting.
Old houses move. Walls aren’t plumb, floors aren’t level, and corners are rarely 90°. The skill of a finish carpenter isn’t fighting that — it’s accommodating it. We measure every corner before cutting a single mitre, and we cut to whatever angle the wall actually is, not what we wish it was.
The five-degree rule
If a corner is within 5° of square, scribe one piece in to absorb the angle and run the cut at 45°. If it’s more than 5° out, cut both pieces to half the actual angle — 50° + 38° if the wall opens at 88°. The result reads as “square” even when the geometry isn’t.
This is the difference between work that ages well and work that opens up at the joints inside two winters. Promises about square corners miss the point — what you actually want is corners that look square and stay tight forever.


