Cost comparision - Elite Airtight
Customers tend to select a coating strictly on a cost per litre basis without considering the volume solids of the paint. The user of a coating should be interested in the cost of finishing a given unit area and not the price per litre.
The coating user receives value only from that portion of the paint which remains as dried coating film after the thinner has evaporated. Volume solids are the key factor in determining coating economies.
THEORETICAL SPREADING RATE
The theoretical spreading rate is a calculation of the amount of coating, on average, applied to a surface, assuming no losses or penetration into the substrate. To provide a uniform finish on a block wall, filling all the perforations and allowing for absorption, a dry film thickness of 225 microns is required.
The true spreading rate and cost can be calculated as follows:
The leading brand matt emulsion has volume solids of 30% and needs to be applied at a dry film thickness of 225 microns to offer a smooth uniform finish.
Elite Airtight has volume solids of 80% and also needs to be applied at a dry film thickness of 225 microns to offer a smooth uniform finish.
The following table summarises the calculations
| The leading brand matt emulsion | Elite Airtight | |
|---|---|---|
| Solids by volume | 30% | 80% |
| Theoretical spreading rate | 30% x 10 = 300 / 225 microns = 1.33m2/litre | 80% x 10 = 800 / 225 microns = 3.55m2/litre |
| Paint consumption | 1 / 1.33 = 0.75 litres per metre2 | 1 / 3.55 = 0.28 litres per metre2 |
| Cost per metre2 | £3.50 per litre / 1.33m2 per litre = £2.63pm2 | £5.50 per litre / 3.55m2 per litre = £1.55pm2 |
Conclusion
The applicator / specifier / client would generally assume that using the less expensive leading brand emulsion would save them money. Nothing could be further from the truth.
By using Elite Airtight, the saving in materials alone would be £1.08pm2.
This materials saving is only the start. To achieve a 225 micron finish using the leading brand emulsion the applicator would need four coats - Elite Airtight needs just two.
Labour is the most expensive part of any project and those costs would be halved.