On-Site Intumescent Coatings

Controlled Intumescent Application for Installed Steel

We apply intumescent coating systems to installed structural steel on new-build, refurbishment and remedial projects. Work is planned around the accepted specification, steel schedule, access, programme and manufacturer documentation, with agreed application and inspection records.

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Video Guide

How On-Site Intumescent Coating Works

This short video explains how intumescent coatings are applied to installed structural steel, including surface preparation, airless application, site-condition checks, WFT readings and final DFT inspection after sufficient drying.

Watch the On-Site Application Guide

Close-up of rusted and corroded structural steel with visible rivets and flaking paint.

Steel Assessment

Steel Condition Informs the Preparation Method

Before application, we review accessible steel for corrosion, mill scale, contamination, damage and existing coatings. The findings are considered against the accepted specification and selected system documentation to agree the required preparation.

Where coating identity or compatibility is uncertain, the issue is raised with the project team and product manufacturer before overcoating.

Application Method

Airless Spray for Controlled Film Build

Where suitable for the selected product and site conditions, airless spray is used to apply planned coats across accessible faces, edges, connections and complex profiles. WFT readings help the application team control wet coat build during the work.

Planned coverage of accessible steel faces and details

WFT readings taken at defined intervals

Application method selected to suit the product and site

Application and Site Conditions

Controlled Application Under Live Site Conditions

On-site application is planned around the selected product, accessible steel, other trades and changing site conditions. Required ambient and substrate conditions are checked against the product documentation, with agreed application controls recorded during the work.

01

Coating Application

Airless Application and WFT Checks

The selected system is applied in planned coats and passes across the accessible surfaces included in the agreed scope. WFT readings are taken during application to guide coat build and identify areas requiring adjustment.

After sufficient drying or curing, DFT measurements are used to assess the applied dry-film build against the accepted member schedule.

02

Application-Condition Checks

Conditions Checked Against Product Requirements

Ambient temperature, substrate temperature, relative humidity and dew point are checked at the stages required by the selected product documentation and agreed project QA plan.

Recorded readings form part of the agreed application records, alongside relevant product, batch and coating-thickness information.

Application Conditions

Required Conditions Checked During Application

Ambient and substrate conditions can affect application and curing. Required readings are taken before and during the work, then compared with the selected product’s published application limits.

Ambient temperature checked at agreed intervals

Substrate temperature checked before application

Relative humidity and dew point recorded where required

Recorded readings are included in the agreed project QA records for review alongside the product, application and coating-thickness information.

Hand wearing a black glove holding two digital meters displaying temperature and humidity readings indoors.

Worker in protective gear and respirator spraying white intumescent fireproof coating on metal beam in industrial setting.

Coating Thickness Control

WFT Checks During Application, DFT After Drying

WFT readings are taken during spraying to help control wet coat build and identify areas requiring adjustment. After sufficient drying or curing, DFT readings are checked against the accepted member-specific schedule for the steel included in the inspection scope.

Suitable gauges checked before use
WFT readings recorded at planned intervals
DFT measured after sufficient drying or curing

Indoor construction site with exposed concrete ceiling, white brick walls, yellow ladder, ventilation duct, and scattered tools on the floor.

Containment and Ventilation

Controls Planned for the Work Area

Spray zones, access restrictions, ventilation and containment are planned through the project RAMS and COSHH assessment. Controls are selected around the product, work area and people who could be affected, including nearby trades and occupants.

Ventilation controls selected for the product and work area

Adjacent surfaces and work areas protected as required

Controls reviewed when site conditions change

Two workers in high-visibility gear and helmets operating red Skyjack scissor lifts inside a large industrial warehouse.

Access and Coordination

Suitable Access Planned for Each Work Phase

MEWPs, scaffolds or other suitable working platforms are selected according to the task, steel geometry and site conditions. Application is sequenced with the principal contractor and other trades around agreed access and exclusion arrangements.

Access method matched to the task and environment

Application sequenced with other site activities

Operative positioning and rescue arrangements planned

Health & Safety

Worker wearing protective suit, gloves, and mask spray painting a white fireproof coating on ceiling beams.

Inspection and Project Records

Checks Recorded Through the Application Process

Agreed checks are completed at defined stages of the work. Records may include preparation, product and batch information, application conditions, WFT and DFT readings, repairs and deviations, giving the project team a clear handover record for the application scope.

Surface Preparation for Structural Steel

Steel condition, contamination, existing coatings and the selected system determine the preparation required. We review the available information and accessible surfaces, then agree a suitable method before application.

View Preparation Methods