Centreline Measurements

Question 1

Centre Line Measurement

Answer 1

The measurement of the net length of a wall along its centre line, excluding any duplication at corners.

Question 2

NRM2

Answer 2

New Rules of Measurement 2, used for measuring brick or block walls net in square metres along the centre line.

Question 3

Perimeter Calculation

Answer 3

Add twice the thickness of the wall at each corner to the internal dimensions to get the perimeter.

Question 4

Figured Dimensions

Answer 4

Dimensions given explicitly on a drawing that should be used for calculations instead of scaling.

Question 5

Scaling Drawings

Answer 5

Used when figured dimensions are not available, but should be checked for accuracy.

Question 6

Internal vs External Dimensions

Answer 6

Figured dimensions can be given for either the internal or external faces of walls, and either can be used for calculations.

Question 7

Mean Girth

Answer 7

The average length of the walls measured from internal or external dimensions, adjusted for wall thickness.

Question 8

Calculating Centre Line

Answer 8

Add half the wall thickness for each external corner to internal dimensions, or deduct for external dimensions.

Question 9

Complex Shapes

Answer 9

Apply the same centre line calculation principles to complex building shapes.

Question 10

Corner Calculations

Answer 10

Add the thickness of the wall for every external angle in excess of internal angles to get the mean girth.

Question 11

Foundation Measurement

Answer 11

Use the mean girth for calculating foundation trenches, concrete footings, and forming cavities.

Question 12

Perimeter of Cavity Walls

Answer 12

Calculate the perimeter for each component: outer skin, cavity, and inner skin.

Question 13

Check Drawing Scale

Answer 13

Ensure CAD drawings are correctly scaled and calibrated before measurements.