A paint and coating specification is the document that sets out exactly how a surface should be coated: the products to use, how the surface must be prepared, how many coats go on, how thick they should be and the standards the finished work has to meet. It turns a vague instruction like “paint the steelwork” into a precise, measurable plan that a contractor can price, apply and be held to. For industrial and commercial projects, it is the difference between a coating that lasts for decades and one that fails within a couple of years.
Halls Decorators works to specifications on industrial and commercial projects across Yorkshire, Lancashire and Greater Manchester. We explain what a specification contains, who produces it, and why getting it right protects both the building and the budget.
What does a coating specification include?
A good specification leaves nothing to chance. It typically covers several linked areas, and each one affects how well the finished system performs.
The substrate and its condition
The specification starts with what is being coated: steel, concrete, masonry, cladding or an existing painted surface. Different substrates behave differently, and the current condition, whether it is bare, rusted, previously painted or contaminated, decides how much preparation is needed before any new coating goes on.
Surface preparation
Preparation is where most coating failures are won or lost. The specification defines the standard required, whether that is abrasive blast cleaning to a recognised grade under ISO 8501, power tool cleaning, or degreasing and washing down. If the surface is not prepared to the stated standard, even the best paintwork will struggle to adhere and the whole system is undermined.
The coating system and number of coats
Most industrial systems are built up in layers: a primer to bond to the substrate and inhibit corrosion, one or more intermediate coats for build and barrier protection, and a topcoat for colour, durability and resistance to sunlight or chemicals. The specification names the products, the order they go on in, and how many coats are required.
Dry film thickness
Coatings are specified by their dry film thickness, measured in microns, because thickness directly affects protection. Too thin and the barrier is weak; too thick and the coating can crack or fail to cure properly. Specifying and then measuring the dry film thickness is how everyone confirms the system has been applied as intended.
Application method and conditions
The specification also states how the coating should be applied, by brush, roller or spray, and the conditions it can be applied in. Temperature, humidity and dew point all affect how paint cures, which is why professional spray painting and other application work is planned around the right environmental window rather than pushed ahead regardless of conditions.
Standards and compliance
Finally, the specification references the standards the work must satisfy. For protecting structural steel against corrosion, ISO 12944 is the common reference point. It classifies environments by how corrosive they are, from low-risk interiors through to very high and extreme exposure, and it links each coating system to an expected durability before major maintenance is needed. Fire, hygiene and environmental requirements, including limits on volatile organic compounds, may also be written in.
Why does a coating specification matter?
It determines how long the coating lasts
The single biggest reason to specify properly is durability. A system matched to the real conditions on site, applied to the right thickness over properly prepared surfaces, is what delivers the fifteen or twenty-plus years of protection that industrial buildings need. Guesswork rarely gets there.
It removes ambiguity from pricing and tendering
When several contractors price against the same clear specification, you are comparing like with like. Without one, each quote may be based on a different system, a different number of coats and a different preparation standard, which makes the cheapest price meaningless and often the most expensive in the long run.
It protects warranties and compliance
Coating manufacturers frequently tie their product guarantees to their systems being specified and applied correctly. A written specification, backed up by records of preparation and dry film thickness, is the evidence that the system was installed as required. On projects with fire or safety obligations, it is also proof the work meets the standards it needed to.
It prevents premature and costly failure
Most early coating failures trace back to the wrong system, poor preparation or coats applied too thin. A proper specification designs those risks out from the start, which is far cheaper than stripping back and recoating a surface that has failed after a year or two.
Who writes a coating specification?
Specifications can come from a number of sources. On larger projects a specifier, architect or corrosion consultant may produce one. Coating manufacturers offer detailed system specifications for their products and the environment they will face. An experienced contractor can also advise on and develop a specification, drawing on knowledge of what actually performs in the field. Often it is a collaboration between all three, which is why involving the people who will apply the coating early tends to produce a more practical result.
Working to specification with Halls Decorators
A specification is only as good as the workmanship behind it. Halls Decorators applies industrial and commercial coatings to written specifications, preparing surfaces to the stated standard, applying the specified system to the correct film thickness, and keeping the records that show it was done properly.
If you have a specification you need pricing against, or you want help developing one for an upcoming project, you can contact the team to talk it through.