Build-Up Method

Lining and Levelling

Lining and levelling is the build up method we use to bring an out of spec substrate back to a planar, properly falling surface before any chemical resistant lining goes down. It is the foundation of most bund lining work, turning a tired, patched or out of level slab into a substrate the rest of the build up can perform on. Without it, even the best topcoat is fighting a losing battle.

OVERVIEW

How Lining and Levelling Works

We treat lining and levelling as a sequenced restoration, not a quick fix. Each stage is completed and verified before the next, the goal being a substrate the chemical resistant lining can be applied to with confidence. Our standard sequence is:

When Is This Required?

  • Survey and assessment: measured fall checks, ponding tests and crack mapping, with the reason the substrate has gone out of spec identified, not just the symptom.
  • Surface preparation: abrasive blasting, scabbling or diamond grinding to remove laitance, contamination and unsound concrete down to a sound, profiled substrate.
  • Crack and defect repair: opening live cracks, reinstating broken arrises, infilling blowholes and repairing localised damage with compatible polymer mortar before levelling.
  • Bonding primer: applied to the prepared substrate and allowed to tack within the manufacturer’s window.
  • Resin screed: self smoothing or self levelling, poured and worked across the bunded floor with falls set by spinner bar or preset datum points.
  • Trowel applied mortar: built up locally where greater thickness is needed to correct deeper irregularities or rebuild damaged areas.
  • Fall verification: a level survey or water stand check confirming the surface drains to the design point with no ponding.
  • Cure and prep: of the levelled layer, ready to receive the chemical resistant lining specified for the bund.

Lining and Levelling Types

Self smoothing resin screeds: pourable, low build epoxy or polyurethane applied at 1 to 3 mm to correct minor irregularities and produce a planar finish.
Fall correction screeds: placed and trowelled to a defined gradient to re-establish positive falls towards a sump or drain where the bund has lost its profile.
Patch and feather repairs: localised levelling targeted at specific defects rather than the full bund, sequenced into a planned outage.
Self levelling underlayments: heavier build systems at 3 to 10 mm, where the substrate has larger profile defects or shallow ponding to correct.
Trowel applied epoxy mortars: heavily filled, high build systems at 6 to 25 mm for deeper repair, broken arris reinstatement and structural levelling.

Lining and Levelling Performance and Thickness

Lining and levelling layers sit between 1 mm and 25 mm depending on what they correct. The levelling layer is not the chemical barrier: it is judged on planarity, falls accuracy and bond strength, while chemical resistance comes from the lining on top. Each variant suits a different level of correction:

  • Self smoothing finishes: a planar, true to falls surface at low build (1 to 3 mm).
  • Self levelling underlayments: moderate fall correction and surface defects (3 to 10 mm).
  • Trowel applied mortars: anything heavier, including step changes, broken arrises and full local rebuild (up to 25 mm).

The levelling layer itself is not the chemical barrier. Its performance is judged on planarity, falls accuracy and bond strength, while chemical resistance is delivered by the lining applied on top of it.

Materials

Compatible Lining and Levelling Materials

Material selection depends on the lining specified for the rest of the bund. The levelling layer must be chemically and mechanically compatible with whatever sits on top. We typically apply:

Epoxy Resins

The workhorse for levelling screeds and mortars. Compatibility with epoxy topcoats and a reliable bond to concrete make it the default across most bunded flooring.

Polyurethane Resins

For PU screed levelling where thermal cycling and substrate movement are part of the design case, particularly under polyurethane topcoats in food, beverage and external bunds.

Polyurea Resins

Rarely used for levelling in pure form, because the rapid cure profile fights the longer working time needed to place and finish a levelling layer. We apply it as the topcoat over an epoxy or PU base.

Vinyl Ester Resins

As chemically resistant levelling mortars on aggressive acid duty, where the levelling layer has to share the chemistry of the FRP or vinyl ester topcoat above.

Novolac Epoxy Resin

For high temperature levelling where the bund operates above the working envelope of standard epoxy mortars.

Advantages

Advantages of Lining and Levelling

  • Planar surface so the topcoat goes on at uniform thickness, with no thin spots over high points or thick spots in hollows.
  • Positive falls so the bunded floor drains rather than ponding against a wall, column or drain edge.
  • Bonds into the substrate, integrating with the existing slab rather than sitting as a loose overlay.
  • Extends asset life by fixing the substrate condition, not just the surface finish.
  • Sets a quality reference for the rest of the build up: once the floor is true, every later operation is faster, cleaner and more predictable.
  • Single specification for multi product or historically patched floors, instead of chasing localised failures.
Limitations

Lining and Levelling Limitations

  • Not a chemical barrier: the levelling layer is the foundation; the topcoat holds the chemistry. A bund cannot return to service on a levelling layer alone.
  • Adds programme time: cure is needed between substrate prep, levelling layer and topcoat. Rapid cure systems compress this but do not remove it.
  • Not a structural fix: a slab with active settlement, water table problems or live cracking needs structural remediation before levelling goes down.
  • Moisture limited: the substrate must be within the manufacturer’s envelope, normally below 4% by weight, before any resin levelling is placed.
  • Heavy fall correction: more than 25 mm is usually better handled by trowel applied mortar systems than a self levelling underlayment alone.
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.

When Choose

When to Choose Lining and Levelling

We specify lining and levelling when one or more of these apply:

Lost falls

The floor ponds water against a wall, column or drain edge.

Repeatedly patched

Years of patching and recoating have left a non planar surface that would compromise any new topcoat.

New lining going in

The substrate needs reprofiling before a chemical resistant lining can perform as designed.

Tight shutdown

The substrate has to be brought back to a known specification before the topcoat goes on.

Concentrated defects

Blowholes and historical damage sit in patches, needing local levelling rather than a full recoat.

One specification wanted

Across a bund that previously carried repair patches of different ages and chemistries.

Applications

Lining and Levelling Applications and Industries

Lining and levelling runs across almost every sector we work in, with the heaviest demand where falls and floor planarity are non negotiable:

Food & Beverage

Restoring falls in production bunds, CIP areas and wash-down corridors, where ponding compromises hygiene as much as containment.

Chemical Processing

Bringing multi-product, historically patched floors back to a single specification before the new chemical-resistant topcoat is applied.

Sewage and Waste Water Treatment —

Re-profiling channel falls and digester surrounds where decades of operation have left low spots.

Power Generation and Transmission

Correcting fall to oil-water separators on transformer bunds where historical patching has produced multiple drainage issues.

Oil, Gas and Petrochemical

Re-levelling tanker offload aprons and fuel bund floors after years of mechanical wear.

Agriculture & Aquaculture

Restoring effluent channel falls in silage clamps and slurry bund floors.

Nuclear Facilities

Preparing active drainage trenches and cell floors to a planar, decontaminable specification before the BS 4247-compliant topcoat is applied.

Preparation

Lining and Levelling Surface Preparation Requirements

  • Prepare the concrete by abrasive blasting, scabbling or diamond grinding to ICRI CSP 3 to 5, removing all laitance, oil, grease and unsound concrete.
  • Repair cracks and defects before levelling, opening live cracks and filling them with compatible polymer mortar.
  • Check moisture is below the manufacturer's threshold, typically under 4% by weight, by hygrometer or calcium chloride test.
  • Confirm temperature is within the resin's envelope (commonly 10 to 25°C) and at least 3°C above dew point, monitored across the day.
  • Apply bonding primer matched to the levelling system, evenly, and overcoat within the tack window.
  • Set datum points and falls on site before pouring, giving a clear visual target for the finished gradient.
QA

Lining and Levelling Quality Assurance and Testing

  • Visual inspection during placement to confirm full coverage, no air entrapment and consistent appearance across the bund.
  • Fall verification by level survey or water-stand test, confirming the new surface drains positively to the design collection point.
  • Thickness checks at representative points using witness cores, ultrasonic gauging or pre-set datum pins.
  • Cure verification by hardness or time-and-temperature monitoring, before any topcoat is applied.
  • Adhesion pull-off testing at agreed locations, confirming bond strength to the substrate against the design value.
  • Pre-handover inspection of the levelled surface against the topcoat manufacturer's substrate requirements, so the operator placing the chemical-resistant lining accepts the substrate before they begin.
  • Handover inspection of the levelled surface against the topcoat manufacturer's substrate requirements, so the lining applicator accepts it before starting.
Frequently Asked Questions

Lining and Levelling FAQs

Self-smoothing screeds correct surface irregularities up to around 3 mm, self-levelling underlayments handle 3–10 mm, and trowel-applied epoxy mortars carry up to roughly 25 mm in a single application. Anything beyond that is normally addressed with a trowel applied mortar system or, where structural fill is needed, a polymer-modified concrete repair before the levelling layer goes on.

Our Work

Featured Case Studies

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