Fire-Resistant Coatings Applied to Perfectly Prepared Steel
Commercial Shot Blasting offers a complete intumescent painting service for structural steel, fire escapes, and industrial metalwork. We shot blast to Sa 2.5, apply certified intumescent coatings, and provide full DFT documentation for fire resistance ratings from R30 to R120.
We assess the steel, confirm the required fire resistance rating (R30, R60, R90, R120), and agree the coating system and DFT specification.
All steel is shot blasted to Sa 2.5 or Sa 3 to remove mill scale, rust, and old coatings and create the correct surface profile for maximum adhesion.
An approved zinc-rich or epoxy primer is applied immediately after blasting to prevent flash rusting and provide the correct base for the intumescent topcoat.
The intumescent basecoat is applied in controlled passes to achieve the specified DFT for the required fire resistance rating. DFT is measured and logged.
A protective sealer or decorative topcoat is applied over the intumescent layer for weather resistance and the required finish colour.
A full DFT survey is carried out and a coating report issued, ready for building control or fire engineer sign-off.
For a smooth handover, the steel, blast work, primer and intumescent system all need to be planned together—not handed from trade to trade at the last minute.
We need the fire-performance requirement, steel condition, access, the specified coating system and compatible primer, the preparation requirement and any checks the project needs. The manufacturer’s guidance and your project specification set the final system and film build.
Freshly prepared steel needs protecting at the right point in the job. On the HB Tunnelling warehouse project in Doncaster, we blasted the steel, applied primer straight after and then moved into intumescent coating as one coordinated job. We will build the right sequence around your coating system and programme.
Before blasting: Mill scale, rust, weld spatter — all must be removed before intumescent application
After blasting: Sa 2.5 clean metal; 40–75 µm profile for intumescent primer adhesion
Intumescent coatings require Sa 2.5 surface preparation as a minimum. Any mill scale or rust beneath the intumescent layer will cause delamination during a fire event, rendering the fire protection ineffective. Shot blasting is mandatory before intumescent application on structural steelwork.
See how a five-person specialist team delivered abrasive blasting, immediate primer protection and intumescent fire-protective painting as one coordinated scope for the HB Tunnelling Doncaster warehouse refurbishment.
Keeping surface preparation and fire protection together reduced handovers between trades and supported continuous progress through the refurbishment programme.
View the HB Tunnelling Doncaster end-to-end delivery case study.
Intumescent paint expands under heat to create an insulating char layer around steel, maintaining structural integrity for the specified fire resistance period — typically R30, R60, R90, or R120.
Intumescent coatings require strong adhesion to perform correctly. Shot blasting to Sa 2.5 removes all contaminants and creates the surface profile needed for maximum mechanical adhesion.
We can achieve fire resistance ratings from R30 to R120 depending on the steel section factor, the coating system specified, and the required DFT.
Yes. We measure dry film thickness on every coated member and provide a full coating report with product data sheets, batch numbers, and thickness readings for building control.
Our mobile units deliver intumescent painting — fire-resistant coatings for structural steel services across 35 counties in the UK. Select a county to see all the towns and areas we cover.
Contact Commercial Shot Blasting for professional intumescent painting — fire-resistant coatings for structural steel services nationwide.
Phone: 07970 566409