Carry out setting out

Setting out is how you transfer a building’s position from the drawings onto the ground — boundaries, building lines, square corners and footing positions, all marked with pegs, profiles and taut string lines. Get it right and every trade that follows works from true lines; get it wrong and the error gets dug, poured and built into the job.

Plan view — the first building line is set back from the boundary; a 3-4-5 triangle squares the second line off the corner peg.

1Plan and prepare

Read the drawings first. Study the work instructions, plans and specifications before you touch a peg, and plan the sequence of work — what gets set out, where, and in what order.
Plan for compliance. The work has to satisfy laws and regulations, relevant Australian Standards, WHS and environmental requirements, manufacturers’ specifications and your workplace’s own procedures — plan around them, don’t bolt them on later.
Select and check your gear. Tapes, string lines, levels (spirit, water, laser or optical), hammer, nails, pegs and timber for profiles. Confirm everything is serviceable; report and tag out anything faulty.
PPE for each part of the task — not one set for the whole day. Eye protection when nailing, gloves when driving pegs, hi-vis and sturdy boots throughout.
Walk the site. Locate underground and overhead services (a Before You Dig Australia enquiry before driving pegs), assess hazards and apply risk controls — including the signage and barricades the job needs.

2Show the site boundaries

Find the survey pegs at each corner of the site. They’re placed by a licensed surveyor and are your only true reference for where the block starts and ends.
Verify before you trust. Check the pegs against the site drawings. A missing, loose or disturbed peg means stop and report — only a licensed surveyor can re-establish a boundary mark.
String the boundaries. Run string lines between the survey pegs so the site boundaries are clearly and accurately shown, matching the site drawings.

3Set out the first building line

Get the setback from the drawings — the distance from the building line to the boundary, or to an existing building.
Rough it in first. Work out the approximate position and length of the line, and the building clearances at each end, from the drawings and the survey pegs.
Build pegs and profiles clear of the future excavation. Each profile must be level across its own crossbar and level with the other profiles — and wide enough to carry marks for the full footing width, not just the wall line.
Nail and string. Drive nails into the profile crossbars at the exact line position, then run a taut string line between them, in true alignment (parallel) with the boundary.

4Set out right-angled corners

Mark the corner with a peg on the set building line, measured true from the adjacent boundary — this peg anchors the whole layout.
Triangulate the right angle. Use the 3-4-5 rule (Pythagoras: a² + b² = c²) off the corner peg. Any multiple works — 3.6 m / 4.8 m / 6.0 m — and the bigger the triangle, the more accurate the angle.
Profiles and string. Install the new profiles at approximately the same level as the existing ones, then set a taut string line on the right-angled alignment.

5Install the other building lines

More profiles, same level. Install profiles for every remaining building line, level with the profiles already established.
Measure, mark, nail. Take the dimensions from the drawings, mark them accurately on the crossbars and drive a nail at each mark.
String every line taut to its nailed locations. A sagging line is a wrong line.

6Check the building lines for square

Measure the diagonals. A rectangle is square when its two diagonals are equal — but only once you’ve confirmed the side lengths are correct first.
Know the tolerance cold: 3 mm over a minimum diagonal of 10 m. Adjust the lines until the diagonals agree within that.
L- and T-shaped buildings: break the shape into rectangles and check each rectangle’s diagonals separately.
Final check. Re-check every measurement against the drawings before anyone digs or pours.

Assessment heads-up

To be assessed as competent you’ll set out one L-shaped and one T-shaped building on a site with fall, to the 3 mm / 10 m tolerance, covering pads, slabs, strips and piers. Practise on a slope, not just a flat yard.

★Know this cold

Standards and quality: the Australian Standards your job specifies for setting out and measurement, plus your workplace’s quality policies — what tolerance applies, and how checks are recorded.
Safety: WHS requirements for the task — site induction, a SWMS where the work requires one, correct PPE, services located before driving pegs, and safe use of hand tools when building profiles.
Line, level and plumb: line is straight alignment between two points, level is truly horizontal, plumb is truly vertical. Every structure on the job depends on all three.
The maths: Pythagoras and the 3-4-5 rule for right angles, equal diagonals for square, working in millimetres and converting between mm and m without slipping a zero.
Reading the drawings: the site plan gives boundaries and setbacks; the footing/slab plan gives the positions and sizes of pads, strips, slabs and piers; the datum gives your level reference.
Flat, sloping and steep sites: always measure horizontally, never along the slope — hold the tape level and plumb down, and step-tape long runs. On fall, cut profile stakes longer on the low side so all crossbars sit at a common level, transferred with a laser, optical or water level.
The process order: plan → boundaries → first line off the setback → square corner by triangulation → remaining lines → diagonal check. Each step relies on the one before it.
Site isolation: it’s your responsibility to keep other workers, plant and the public off the set-out — signage, barricades and communication protect both people and your lines.

Devices — capabilities and limits

Device	Best for	Watch out
String line	A straight reference between two points over long runs	Must be taut; sag or wind movement gives a false line
Long steel / fibreglass tape	Set-out dimensions and diagonal checks	Keep it taut, level and kink-free; measure horizontally on slopes
Spirit level	Short-range level and plumb	Only as accurate as its length; check it by end-for-ending
Water level	Transferring level over distance and around corners	Slow; air bubbles in the hose ruin the reading
Laser level	Fast level transfer across a whole site, one operator	Needs regular calibration checks; use a detector in bright sun
Optical (automatic) level	Precise level transfer with a staff	Needs correct set-up and usually a second person on the staff

!Where people slip up

Measuring along the slope

A tape run down a fall reads longer than the true horizontal distance, so the building comes out oversized. Hold the tape level and plumb down to the mark — step-tape long runs on steep ground.

Checking diagonals before checking lengths

Equal diagonals only prove square if the side lengths are already correct — a layout can have matching diagonals and still be the wrong size. Confirm every dimension against the drawings first, then check the diagonals.

Profiles at different levels

If the crossbars aren’t level with each other, every height you transfer and every plumb-down on a sloping site is out. Level all profiles to a common height with a laser, optical or water level before you string a single line.

Trusting a lonely survey peg

Pegs get knocked by deliveries and machines. Verify pegs against the site plan before you build off them, and if one is disturbed or missing, stop — only a licensed surveyor can re-establish a boundary mark.

One unlabelled nail per profile

Weeks later, nobody remembers if that nail is the wall face or the footing edge. Mark and label the footing width and building line on every profile so the excavation goes to the right line.

A–ZMini-glossary

Setting out: Transferring the position of a building from the drawings onto the ground using pegs, profiles and string lines.
Survey peg: A marker placed by a licensed surveyor at the corners of the site, defining the legal boundary.
Profile (hurdle): A horizontal crossbar fixed to stakes, set clear of the excavation, that carries nails marking the building and footing lines.
Building line: A string line representing the face of the building, set out from the drawings.
Setback: The required distance from the boundary (or an existing building) to the building line, taken from the drawings.
Datum: A fixed reference point from which all levels on the site are measured.
Fall: The slope of a site — the difference in ground level from one point to another.
Line, level and plumb: Straight alignment, true horizontal and true vertical — the three references all construction depends on.
Triangulation / 3-4-5 rule: Using a triangle with sides in the ratio 3:4:5 (from Pythagoras) to set out an exact right angle.
Diagonal check: Measuring both diagonals of a rectangle; equal diagonals confirm square corners — to 3 mm over a minimum 10 m diagonal in this unit.
Pad, strip, slab and pier: Footing types: an isolated pad under a point load; a continuous strip under walls; a concrete slab floor; a pier — a column-like footing, often on sloping sites.
Taut: Pulled tight with no sag — the only acceptable state for a string line.
SWMS: Safe work method statement — the document setting out how high-risk construction work will be done safely.

That’s the lot

Nine sections, one tolerance to remember — 3 mm over 10 m. Revisit anything from the jump list, and when it has all soaked in: