Build-Up Method

Protective Coatings

Protective coatings is the build up method we use most often across bund lining work. Multi coat resin film systems go straight onto the substrate to deliver chemical, mechanical and aesthetic performance in one engineered package. It sits between substrate preparation and reinforced laminate work, and is the default where chemistry is moderate, the substrate is sound and reinforcement is not required.

Definition

How Protective Coatings Works

We treat protective coating as a sequenced multi coat operation, not a single application. Each layer has a defined role, bond, build and protect, and the system only performs as designed when every coat goes on within its window onto a properly prepared coat below. Our standard sequence is:

When Is This Required?

Substrate assessment: concrete soundness, surface profile, moisture content and any contamination from previous service.
Surface preparation: abrasive blasting, scabbling or grinding to expose a sound, profiled substrate the primer can bond to.
Detail repair: cracks, blowholes, broken arrises and localised damage made good with compatible polymer mortar before coating.
Penetrating primer: applied at the manufacturer’s rate and allowed to tack within the recoat window.
First body coat: pigmented, applied by roller, brush or spray to a defined wet film thickness, with falls, coves and details worked by hand.
Inter coat keying: where specified, by light abrasion or solvent wipe to secure adhesion before the next layer.
Second body coat: built to the target dry film thickness, often at right angles to the first coat to control lap lines and pinholes.
Topcoat: chemical resistant, UV stable or slip modified as the duty requires, giving the visible finish and the working surface.
Cure and inspection: before any return to service, handing the bund over only when measured performance matches the specification.

Protective Coating Types

Solvent free epoxy systems: the modern default for most bund duties, no VOC and good build per coat, applied as a primer, body and topcoat regime.

Water based epoxy systems: for light duty work and where solvent and VOC controls rule out other options.

Sprayed polyurea systems: 100% solids, ultra rapid cure, applied in a single high build pass for short outage work.

Novolac epoxy coatings: multi coat builds for elevated temperature and concentrated acid duty.

High solids epoxy systems: slightly thicker per coat than solvent free, where film build at moderate thickness is the priority.

Polyurethane topcoats over epoxy basecoats: the chemical resistance and build of an epoxy body with the UV stability and colour retention of a polyurethane finish.

Vinyl ester multi coat systems: a coating rather than a lay up where chemistry is aggressive but reinforcement is not needed.

Direct to metal (DTM) systems: for steel substrates and water tank lining duties, where the primer bonds to prepared steel without an intermediate barrier.

Protective Coating Performance and Thickness

A typical protective coating in bund service is built to 0.5–2 mm dry film thickness, with the right film build matched to the duty:

Light duty: 250 to 500 microns, for ancillary bunds, plant rooms and lower risk areas with routine spillage rather than continuous chemical contact.
Standard duty: 500 to 1,000 microns, the typical specification for most UK bunds, including hydrocarbon storage, food production floors and general industrial chemistry.
Heavy duty: 1 to 2 mm and beyond, built as a multi coat film for tanker offload aprons, drum decks and aggressive chemical service.

Across every tier, the system delivers a smooth, continuous, chemical-resistant barrier with measurable adhesion, holiday-free coverage and a service life that comfortably reaches 15–25 years on most duties when properly maintained.

Materials

Compatible Protective Coating Materials

All five resin families in our range can be applied as a protective coating; the choice is driven by duty, not application method. We typically apply:

Epoxy Resins

The workhorse for most coating specifications: reliable chemical resistance, sound adhesion to concrete and steel, and a strong balance of cost and performance. The default for most bund lining and water tank lining projects.

Polyurethane Resins

A topcoat over epoxy where UV stability, colour retention or external exposure matter, or a full PU build where flexibility and crack bridging are part of the design case.

Polyurea Resins

Sprayed as a single high build coating where rapid return to service is essential, including live data centre, retail forecourt and short shutdown work.

Vinyl Ester Resins

A multi coat chemically resistant coating where reinforced lay up is unnecessary but acid and oxidiser performance is required.

Novolac Epoxy Resin

For elevated temperature, concentrated acid and aggressive solvent duty where standard epoxy coatings would soften or degrade.

Advantages

Advantages of Protective Coatings

Faster programme than reinforced lay-up, with multi-coat application typically completing in days rather than weeks
More cost-effective per square metre than reinforced laminate or trowel-applied mortar systems, with whole-life cost favourable on most standard duties
A wide chemistry palette, allowing the same application method to deliver very different chemical performance by changing the resin
Excellent surface finish, including hygienic, slip-resistant or aesthetic options
Easy to inspect, easy to maintain and straightforward to repair locally without disturbing the rest of the bund
Suitable for almost any bund geometry, including walls, floors, coves, sumps and detail areas
Compatible with most existing substrates, provided preparation is done to the specified standard

Limitations

Protective Coating Limitations

No reinforcement, the coating relies on the substrate for mechanical performance, and a poor substrate cannot be saved by a thicker coating
Less mechanical strength than reinforced lay-up or trowel-applied mortar systems, with point loading and impact more likely to cause local damage
Vulnerable to inter-coat adhesion failures if recoat windows are missed or surfaces are contaminated between coats
Thinner than reinforced systems, which is fine for most chemical duties but inadequate where permeation across decades of service is the design case
Substrate movement beyond the system’s crack-bridging capacity will eventually telegraph through the coating
Aggressive acid duty at high concentration is sometimes better held by a vinyl ester lay-up, even where a coating would technically perform

Get Expert Lay-Up Advice

Need a lay-up specified for a demanding bund?

Speak to Reschem about the right laminate build-up, resin choice and inspection regime for aggressive chemical duty, confined structures or long-life containment assets.

01773 748 895 Enquire Now

Protective Coatings

When to Choose Protective Coatings

We specify a protective coating build up when the duty matches. The typical decision criteria are:

Moderate chemistry

Hydrocarbons, dilute acids and alkalis, food and beverage CIP and most utility side duties.

Sound substrate

No structural movement or live cracking that reinforcement would have to address.

Programme matters

A multi coat system fits a planned outage window where lay up would not.

Cost constrained

The duty does not justify the extra capital of a reinforced or trowel applied system.

Conventional geometry

No need for reinforcement around irregular features or structural integration.

Consistency wanted

A known, well understood build up specified, applied and maintained the same way across multiple bunds.

Renewable surface

Recoating or planned refresh is part of the asset management approach, with the coating treated as renewable rather than once and done.

Applications

Protective Coating Applications and Industries

Protective coatings is the build up most operators meet when they first specify a bund lining, and we deliver it across every sector we work in:

Oil, Gas and Petrochemical

Fuel storage bunds, plant rooms and tanker offloading aprons where epoxy and polyurethane multi-coat systems are the established default.

Chemical Processing

Utility and ancillary bunds, dosing skids and reagent stores where chemistry is moderate and reinforcement is not required.

Food & Beverage

Production floor bunds, CIP areas and ingredient stores where hygiene-led, easily cleaned coatings are the design case.

Sewage and Waste Water Treatment

Reagent stores, plant rooms and lower-risk treatment plant bunds outside the most aggressive BSA zones.

Power Generation and Transmission

Transformer bunds, generator compounds and plant rooms across DNO, transmission and renewables sites.

Agriculture & Aquaculture

Fertiliser bunds, fuel oil compounds and lower-risk farm assets where coating chemistry handles routine spillage.

Nuclear Facilities

Qualified, BS 4247-compliant coatings on active-area floors, support areas and lower-risk inactive bunds.

Prep

Protective Coating Surface Preparation Requirements

Prepare concrete by abrasive blasting, scabbling or diamond grinding to ICRI CSP 2 to 4 depending on the system, removing all laitance, oil, grease and unsound concrete.
Prepare steel by abrasive blasting to SA 2.5, primed within the manufacturer's window before flash rust forms.
Check moisture is within the resin's envelope, normally under 4% by weight, by hygrometer or calcium chloride test.
Keep it clean: every coat goes onto a clean, dust free surface, with abrasive waste fully extracted before the next material is opened.
Detail repair before priming, reinstating cracks, blowholes and broken arrises with compatible polymer mortar.
Confirm temperature is within the specified range and at least 3°C above dew point, monitored across the day.

Protective Coating Quality Assurance and Testing

Visual inspection during application, between coats and at handover, to confirm coverage, colour, appearance and absence of defects.
Wet film thickness measured with a wet comb during application, so corrections are made while the material is still workable.
Dry film thickness measured post-cure with calibrated gauges (magnetic for steel, ultrasonic for concrete) at representative points across the bund.
Holiday (spark) testing of the finished system to identify pinholes, voids and discontinuities that visual inspection cannot pick up.
Adhesion pull-off testing at agreed locations, confirming bond strength to the substrate against the design value.
Pre-handover hydrostatic (wet) test of the bund, where the operator's specification or environmental permit requires it.

Frequently Asked Questions

Protective Coating FAQs

How much disruption should businesses expect during protective coating application?

Most coating projects are delivered with moderate, time-boxed disruption typically several consecutive days for substrate prep, application and cure, rather than the weeks that lay-up systems require. Rapid-cure polyurea systems can compress this further where the operator can absorb a single short, intense outage.

How long does each stage of the protective coating application usually take?

Are protective coatings suitable for bunds exposed to standing liquids or frequent washdowns?

Can protective coatings be used as a long-term standalone bund lining solution?

How well do protective coatings handle thermal cycling and temperature extremes?

Can protective coatings be used in confined or hard-to-access bund areas?

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