Even if your spirit level is not very good. Something I was taught very early on in my building career was that spirit levels “tell lies”…. Now that was probably just my old boss talking, after I’d pointed out something he built wasn’t level, but in a way he was right. Spirit levels DO tell lies, about 0.15mm per M usually. Now that only adds up to 1.5mm in a 10m run which is not too much of a worry, but that’s when the level is brand new. After a …
