Civil Engineering Reference
In-Depth Information
90 × 45 pine 3.6 long, 4 of; or
3.6 long 90 × 45 pine, × 4
Where as the tradesperson will record the information as:
90 × 45 MGP10 4/3.6; or alternatively
90 × 45 4/3.6
and he or she will tell the attendant what type material is required.
The '4' is obviously the number of pieces required.
The '/' is referred to as at.
The '3.6' refers to the length of the timber required.
When ordering windows the height of the window is always mentioned before the
width. When ordering doors it is assumed that the doors will be 2040 high unless you
specify otherwise. The other standard height for doors is 2340 - this is 2.34 metres, not
centimetres, as that would be a door with a height approximately the same width as your
thumb.
Centimetres don't exist in the building industry
One of the most common errors in terminology is the use of centimetres. Within the
building industry you need to understand that centimetres do not exist. The use of
centimetres will only bring confusion. As a simple example, if you order timber with
centimetres in mind it will have no bearing on the supplier, as they do not give reference
to centimetres. If you order particleboard sheeting cut to size at 90 × 240 you would be
expecting a piece of material a little wider than a standard door and as high as the ceiling
in a project built home. What you are likely to be supplied is a piece of particleboard
close to the length of your hand and less than half its width. The centimetre
measurements equates to 900 mm or 0.90 of a metre × 2400 mm or 2.4 metres, however,
the supplier is more than likely to consider them as millimetres for they only refer
to millimetres and metres. When interpreted in terms of millimetres it equates to
90 mm × 240 mm.
Second-hand timber
When timber is used in a structural application it must be understood that the use of
second-hand timber is a privilege, not a right. I am sure that many readers will, at this
point, have feelings of dismay and may even wish to reject this statement but I assure you
it is true and I shall explain why. The building code requires that timber used to carry
load in the construction of a house, or any other building for that matter, must have the
capacity to carry the load. If you check the timber specification schedule on your
approved building permit it will have details of various grades of timber which might
present as MGP with a number following for pine, or 'F' with a number following for
other materials. These terms refer to the measurable strength of the material that is to
be supplied.
In the seventies and eighties, trained people visually graded a high percentage of the
timber. They understood that density of the timber and the direction of the grain in
