The Importance of a Millimetre

Recently I’ve had two experiences of being 20mm out. 1) Width of a timber vanity top. 2) Height of a plantation shutter frame. 20mm is just 2cm so it doesn’t seem like abig deal. In both cases, it made the items unusable for the intended purpose.

In building and construction, the importance of a few millimetrescannot be overstated. A building can fail its inspection if the Surveyor finds that the frame, for example, is outside the allowable ‘tolerance’ by as little as 2mm! 2mm is so tiny it can be hard to read on a tape measure, but what might be 2mm at one end extrapolates over the length and
you’ll find your walls out of square at the other! It’s a pretty big deal.

The Victorian Building Authority (VBA) publishes the Guideto Standards and Tolerances for builders and tradespeople, but you don’tneed to worry about that unless you’re an owner-builder. Nevertheless, when you’re doing DIY for renovations or home improvements, it’s critically important not to think “She’ll be right”.

Measure Twice, Cut Once

This is an old adage and for good reason. Once you’ve made your cut there’s no goingback! If you’ve overcut you may get asecond chance (if you have precision tools), but if you over-cut, well, say good bye to your material.

Accurate measuring will form the basis of everything you do. No matter what it is – whether curtain drop, distance to a socket, length of a tiled wall, or the kitchen dimensions when planning new cabinetry. Small errors could cost literally thousands of dollars!

 

It’s also important to understand what you’re measuring, and to be clear when communicating it. Here are a few common mistakes to avoid and suggestions to get it right:

  • Builders & trades use millimetres (andmetres). An exception to this standardis window treatments. They usecentimetres. Either way, be sure you don’t tell them 236. It’s either 236cm or 236mm.
  • Measuring windows depends if it’s for curtains, blinds, shutters etc, because each will require slightly different
    information. Finished length or drop, the total width (eg: if curtains extend on each side of the window) versus
    internal window frame width. For venetians or shutters you’ll be asked if it’s a reveal (inside frame) or face
    fix (outside frame).
  • When tiling, the box will usually state tile size and square meterage they cover, but it’s approximate. Don’t forget to include the grout spacingwhich can be as little as 2mm and as much as 7mm, depending on the tile type (rectified or not).
  • Length is usually the longest side and is noted first (eg: 350 x 200), but not always. If in doubt, use abbreviation (eg: 350mm L x 200mm W).
  • You know length and width, but don’t forget height and depth. Height is basically distance from the ground, such as a benchtop, and depth is front to rear (eg: how far it protrudes from a wall). But depth is also often used when talking about thickness (eg: a solid timber bench top might be 35mm deep).
  • If you need floor or wall surface, area is measured as Length x Width (eg: 4m x 2.4m = 9.6m2). This will be useful for tiling.
  • If you need to know the volume (eg: for concrete) it’s length x width x height (eg: 12m x 6m x 150mm = 1.08m3).
  • Carpet (and many other items) are sold by lineal metres. So even though carpet covers floor area, it will be sold in lineal metres. You’ll buy 5 lineal metres, which means 5m long x the width of the specific carpet (which will differ between carpet manufacturers). You MUST check to make sure it’swide enough for your space!

A lot of people are eager to move to the installing or doingstage of a project, but careful measuring and planning will make the world of difference to your ultimate success. Be sure to give this step the time it deserves and get it right the first time. Happy renovating.