Plastering & Insulation Formulas

Before reading this article, please make sure you are familiar with Measurement - Parts & Labour in Groundplan.

Parts, labour and the formula used are unique to each project and company, the information below details the example of Plastering 2.4m ceilings being measured on a 2D plans and the formulas used to calculate additional parts and labour.

Plasterboard

When calculating plasterboard, there are a few common scenarios and formula that can be used:

1. Per Meter - If you charge out per Linear meter measured.

Formula: len

Breakdown:
len - the number of meters measured;
ceil(len) - (optional) to show the meters measured by rounding up a decimal value to the next whole number.

2. 6m x 1.2m sheets required - calculate the number of 6m x 1.2msheets required, when the wall height is 2.4 meters.

UOM: sheets
Formula: len * 2.4/ 7.2

Breakdown:
len - the number of meters measured;
* 2.4 - multiplying by the wall height to turn meters into sqm;
/7.2 -dividing by the area of a single sheet (6m*1.2m = 7.2m2);
ceil(xxx) - (optional) to show the number of whole sheets by rounding up a decimal value to the next whole number.

3. Sheets required - calculate the number of sheets required for a 6m sheet length, where 2 sheets are required to cover the wall area when the height is 2.4 meters.

UOM: sheets
Formula: len/6*2

Breakdown:
len - the number of meters measured;
/6 - dividing the length measured by the sheet length;
* 2 -multiplying by the number of sheets needed for the wall height;
ceil(xxx) - (optional) to show the number of whole sheets by rounding up a decimal value to the next whole number.

Cornice

When calculating cornice, here are two common scenarios and formula that can be used:

1. Per Meter - to measure the meterage of cornice required.

Formula: = len

Breakdown:
len - the number of meters of measured;
ceil(len) - (optional) to show the cornice measured by rounding up a decimal value to the next whole number.

2. Cornice in 4.2m lengths - Calculating the cornice, when you purchase the cornice in 4.2m lengths.

UOM: lengths
Formula: len/4.2

Breakdown:
len - the number of meters measured;
/4.2 -dividing by the length you purchase the cornice in;
ceil(xxx) - (optional) to show the number of lengths by rounding up a decimal value to the next whole number.

Insulation / Pink Batts

To quantify the number of bags of 5.8m x 11.6m insulation required.

UOM: bags
Formula: len * 2.4/ 67.28

Breakdown
len - the number of meters measured;
* 2.4 - multiplying by the wall height to turn meters into sqm;
/67.28 -dividing by the area of a roll of insulation(5.4m * 11.6m = 67.28m2);
ceil(len) - (optional) to show the number of bags by rounding up a decimal value to the next whole number.

Total Wall Area

This part is used to quantify the sqm of walls that need to be plastered, commonly used where you have multiple measurements being used to quantify the same parts e.g. 2.4m walls and 2.8m walls

UOM: m2
Formula: len * 2.4

Breakdown:
len - the number of meters measured;
* 2.4 - multiplying by the wall height to turn meters into sqm.

Door & window removal

If your calculations include door and window removal, these would be calculated using additional measurements.

Please see the following article on Door and window removal for formula examples.

The Final Measurement

For additional formula assistance, please see our Measurement Parts & Labour FAQs or click on help and click send us a message to contact one of our team.