Paint and Coatings: Where Specification Determines How Long It Lasts

Paint is bought by area and judged by how it looks in three years. The factors that decide the difference.

Paint is the most visible finish and the one selected with the least technical attention. Its performance depends on the system rather than the colour, and the difference between a coating that lasts and one that does not is mostly in preparation and specification.

What this number does and does not include

This covers paint and coating systems on internal and external surfaces. It excludes the substrate construction, which determines much of the outcome and is a separate decision.

Surface preparation

Cleaning, repair and priming of the substrate, which determines adhesion and therefore life.

• Pushes it up: Poor substrates, previous coatings requiring removal and contaminated surfaces.
• Brings it down: Nothing worth reducing. Preparation is where coating failures originate.
• How to control it: Specify preparation explicitly and inspect it before painting. This is the least visible and most consequential part of the work.

Primer and system compatibility

The base coat that bonds to the substrate and provides the surface for subsequent coats.

• Pushes it up: Specialist primers for difficult substrates.
• Brings it down: Using a complete system from one manufacturer rather than mixing products.
• How to control it: Use a single manufacturer's system so compatibility is established, rather than combining products that were not designed together.

Number of coats and coverage

The applied thickness, which determines both appearance and durability.

• Pushes it up: Deep colours requiring additional coats, and textured surfaces consuming more material.
• Brings it down: Realistic coverage rates rather than optimistic ones.
• How to control it: Specify coats and check material consumption against the area covered, since thin application is invisible and shortens life.

External coating specification

Systems designed for exposure to sun, temperature variation and dust.

• Pushes it up: Higher performance systems and colours prone to fading.
• Brings it down: Colours and systems chosen for this climate rather than for appearance alone.
• How to control it: Ask the manufacturer what performance to expect in this climate and specify accordingly, since general purpose external paint degrades faster here.

Access for application and renewal

Getting to the surface, which for external work at height is a significant cost.

• Pushes it up: Multi-storey buildings and surfaces requiring specialist access.
• Brings it down: Nothing, though the cost should be counted in the renewal cycle.
• How to control it: Include access cost when comparing coating systems, since a longer lasting system saves the access cost as well as the material.

Costs that never appear on the first page

• Renewal cycles including access, which recur for the life of the building.
• Remedial work where coatings fail prematurely due to preparation.
• Colour matching for repairs, which is difficult once the original has weathered.
• Protection of adjacent finishes during application and renewal.

Keeping the budget honest

Compare coating systems on cost per year of service including access, not on cost per litre. A system lasting twice as long at 30 per cent more cost is substantially cheaper, particularly at height.

• At specification, confirming the system suits the substrate and exposure.
• Before application, inspecting preparation.
• During application, checking consumption against coverage rates.
• At renewal intervals, assessing performance against expectation.

If you are procuring materials for a project, Domira can specify, source and verify them against the standards your drawings actually require.