Concrete and Floor Coating Standards in Industrial Facilities, and Consumption Calculation
Most floor coating failures originate in the concrete, not the paint. Moisture control, laitance, surface profile, and how consumption is actually calculated — including site allowances.
Where Do Floor Coating Failures Come From?
The large majority of failures in industrial floor coatings do not stem from product quality. Site experience shows a consistent picture: the overwhelming share of problems originates in the concrete itself and in the preparation stage.
The reason is straightforward. The floor is the most demanding surface in a building. Forklifts run over it, pallets scrape it, chemicals are spilled on it, temperature changes, and moisture comes from beneath. The smallest shortcoming in preparation that a wall would tolerate returns as delamination within months on a floor.
The basic rule: A floor coating can never be stronger than the concrete it is applied to. A flawless application over a weak or contaminated surface lifts together with that surface.
Three Mandatory Checks Before Application
1. Moisture check
This is the most critical and most frequently skipped step. If the concrete is taking up moisture from beneath or within, the epoxy film traps it; the accumulating vapour pressure blisters the coating and separates it from the surface.
Moisture comes from two sources. The first is the construction water in the concrete itself — a newly poured slab must not be coated before curing is complete. The second is capillary moisture from the ground; where there is no damp-proof membrane under the slab, that moisture is continuously replenished and never stops.
Where there is doubt, carry out a moisture measurement before application. As a practical preliminary check, tape an impermeable sheet tightly to the floor and see whether condensation appears beneath it after a period. If it does, do not proceed with the coating.
2. Surface strength and laitance
At the very top of a concrete surface sits a thin, weak film of cement brought up during trowelling. If that layer is left, the epoxy bonds to the laitance rather than the concrete and lifts with it under the first load.
Laitance must be removed mechanically. Chemical etching is not an adequate alternative and is not recommended for industrial work.
3. Surface profile
For the epoxy to key in, the concrete must have a certain roughness. On a surface finished as smooth as a mirror the coating finds no mechanical grip. The preparation method is chosen according to the thickness of the coating to be applied:
| Method | Profile produced | Suitable system |
|---|---|---|
| Diamond grinding | Low–medium | Thin film, paint-type coating |
| Milling | High | Thick coating, heavy repair |
| Abrasive blasting | Medium–high | General purpose, large areas |
Whichever method is used, dust must be removed afterwards with an industrial vacuum. A brush does not lift the remaining fine dust, and that dust translates directly into loss of adhesion.
System Selection
| Use | Load profile | Suitable system |
|---|---|---|
| Warehouse, light traffic | Pedestrian + light pallet | Primer + thin film epoxy |
| Production area | Forklift, continuous traffic | Primer + medium build epoxy |
| Heavy industry | Heavy load, impact | Thick epoxy or mortar system |
| Food facility | Washdown, hygiene | Non-porous, disinfectant-resistant system |
| Car park, exterior | UV exposure | UV-resistant topcoat required |
The limit worth knowing about epoxy systems is their sensitivity to ultraviolet light. On surfaces in permanent sunlight epoxy yellows and loses gloss. That is an aesthetic change and does not remove the protective function, but where appearance matters outdoors a UV-resistant topcoat should be planned.
Consumption Calculation: From Theory to Reality
Consumption is the line item most often got wrong in quotations, and the cause is nearly always the same: using the theoretical spreading rate directly.
Theoretical consumption is calculated on the assumption that the product is applied to a perfectly flat surface, with no losses, at exactly the intended thickness. None of those conditions occurs on site.
To arrive at real consumption, three separate allowances are added on top of the theoretical figure:
- Surface absorption allowance: Porous, ground concrete draws a significant amount of product into itself on the first coat. This allowance is felt most in the primer coat.
- Surface roughness allowance: The deeper the profile, the more material is needed for the same apparent thickness.
- Application loss allowance: Material left in equipment, dried in the container, overrun at edges. This allowance is lower for roller application and markedly higher for spray.
The calculation is built in this order:
First establish the net area — deduct machine plinths, columns and areas not to be coated from the gross floor area. Then calculate the theoretical quantity required per coat and multiply by the number of coats. Finally add the allowances above.
Worked example — shown only to illustrate the method; real values must be taken from the product technical data sheet:
| Step | Example value |
|---|---|
| Gross floor area | 1,000 m² |
| Deducted areas | 60 m² |
| Net area | 940 m² |
| Number of coats | Primer 1 + topcoat 2 |
| Example theoretical rate | 1 L / 8 m² for primer, 1 L / 5 m² for topcoat |
| Primer theoretical | 940 ÷ 8 = 118 L |
| Topcoat theoretical | (940 × 2) ÷ 5 = 376 L |
| Absorption + roughness allowance | Held higher for the primer |
| Application loss allowance | Low for roller, high for spray |
The square-metre figures in the table are examples. When preparing a real quotation, the spreading rate from the product's own technical data sheet belongs in those places, and the allowances should be set according to site conditions. On a freshly ground, porous floor the primer allowance is markedly higher than on an older, more closed slab.
Mixing and Pot Life
In two-pack epoxy systems, resin and hardener must be mixed exactly to the ratio given by the manufacturer. Mixing by eye is the most common and most expensive mistake in epoxy work.
Insufficient hardener leaves the surface permanently tacky; that condition cannot be corrected and the coating has to be removed. Excess hardener produces brittleness and surface defects.
Mix with a low-speed stirrer, scraping the bottom and sides of the container. Mixed material has a limited working time; once it expires the material heats up in the container and begins to set. Never prepare more than can be applied within that window.
Putting Into Service
Curing is progressive and the sequence must not be short-circuited. The surface becomes walkable first, then takes light load, and reaches full chemical resistance last. Starting forklift traffic or chemical contact too early leaves permanent marks and loss of adhesion in a film that has not finished curing.
Frequently Asked Questions
When can newly poured concrete be coated?
What has to be waited for is the condition of the concrete, not a date. Cement hydration must progress and free moisture must leave the slab, and that period varies considerably with slab thickness, ambient temperature, ventilation and whether there is a membrane beneath the slab. Coating too early produces two problems at once: alkali at the surface attacks the binder in the coating, and escaping moisture blisters the film from beneath. The decision should be made by measurement, not by calendar.
What happens if laitance is not removed?
The coating bonds to the weak cement film on top of the concrete rather than to the concrete itself. Everything looks fine for the first months; the problem emerges when forklift traffic or point loading begins. The coating lifts in sheets together with the laitance beneath it. This is a cohesion failure rather than an adhesion failure, and the only remedy is to strip the floor completely and prepare it again.
Why does consumption always come out higher than calculated?
Because the calculation is usually made on theoretical spreading rate with no site allowances added. The theoretical figure assumes application to a perfectly flat surface with no losses. In reality porous concrete absorbs product on the first coat, the profile of a ground surface demands more material for the same thickness, and material is left in equipment and containers. A quotation prepared without those three allowances comes out short almost every time.
Can epoxy flooring be used outdoors?
It can, but the limit on appearance needs to be understood. Epoxy is sensitive to ultraviolet light; on surfaces in permanent sunlight it yellows and loses gloss over time. That change does not remove the protective function and the coating continues to hold its mechanical and chemical resistance. Where colour and gloss matter outdoors, however, a UV-resistant topcoat should be planned.
When should a floor coating be renewed?
Renewal should happen before wear reaches the concrete. When the surface dulls, traffic patterns become pronounced and colour is lost, the coating is approaching the end of its protective life; at that stage cleaning and a topcoat refresh are usually enough. Once wear has gone through to the concrete or delamination has started, the work is no longer renewal but complete replacement, and it costs many times more.
