Steel Structure Painting

The structures we paint

We paint load-bearing metal structures and steelwork on industrial sites, in place, often while operations continue. The goal is to protect the steel against corrosion; appearance and colour coding follow.

• Industrial building frames: columns, beams, roof trusses, bracing and process buildings.
• Walkways, stairs, platforms and handrails.
• Conveyors, conveyor galleries and transfer towers.
• Overhead cranes and crane runways: girders, rails, brackets and trolleys.
• Pipe supports and pipe racks (corrosion protection).
• Stacks, ducts, towers and pylons.

The service is for industrial sites only. Work is carried out by our crews and qualified subcontractors, under one quote and one inspection file.

Spot repair, overcoat or full removal

The choice between spot repair, overcoat and full removal is based on the condition of the existing paint, measured rather than judged by eye. Rust extent is rated to ISO 4628-3 or ASTM D610, then adhesion and existing film thickness are checked.

• Spot repair: rust limited to isolated points, sound paint elsewhere. The rusted areas are prepared, primed and topcoated, and nothing else.
• Overcoat (spot repair plus full coat): more widespread rust but paint still well bonded. After spot repairs, a compatible full coat evens out the protection. The old film must be able to carry the weight and stress of one more coat.
• Full removal: general rusting, flaking paint or poor adhesion. Everything comes off and a new system goes on.

Zone-by-zone repainting is often the best option: full removal where condition requires it, overcoat elsewhere. Our article on maintenance painting of steel structures sets out the method.

Surface preparation and paint system

Preparation and system are chosen together: a zinc-rich primer needs blast-cleaned steel, while a surface-tolerant primer can go on power-tool-cleaned steel.

• SSPC-SP 2 (hand tool cleaning): scrapers and wire brushes, for minor touch-ups where nothing else is possible.
• SSPC-SP 3 (power tool cleaning): powered brushes and discs, for spot repairs and areas near sensitive equipment.
• SSPC-SP 11 (power tool cleaning to bare metal): removes everything and leaves a profile, where blasting is not allowed but a good primer is required (power tool cleaning).
• SSPC-SP 6 (commercial blast cleaning): common for epoxy systems in moderate exposure.
• SSPC-SP 10 (near-white blast cleaning): for zinc primers and severe environments (abrasive blasting).

The system follows the site's ISO 12944 corrosivity category. Outdoors, the common build remains a zinc primer, an epoxy intermediate and a polyurethane topcoat; in a dry interior, a simpler system is enough. The thickness of each coat comes from the manufacturer's data sheet. For other system options, see our reference page on protective coatings.

Steel structure painting procedure

Painting a steel structure follows six steps, planned with operations.

• Survey: condition rated by zone, access, equipment below, possible shutdown windows.
• Quote and plan: method by zone, system coat by coat, access, containment, schedule coordinated with your shutdowns.
• Set-up: access, protection of equipment and product, containment of abrasive and overspray.
• Preparation: degreasing, preparation to the specified grade, dust removal.
• Application: stripe coat on edges, welds and bolting, then full coats, with dew point and steel temperature monitored.
• Inspection and records: thickness readings, condition logs, photos, data sheets and batch numbers.

Inspections and standards

Each coat is checked before the next, and the results go into the close-out file.

• SSPC-PA 2: dry film thickness measurement, with the number of readings and the tolerance the standard sets per area (dry film thickness).
• ISO 12944: corrosivity category and system selection (ISO 12944 explained).
• SSPC-SP 2, SP 3, SP 11, SP 6 and SP 10: preparation grade checked before each primer.
• ISO 4628-3 or ASTM D610: rust rating at the initial survey, used as the baseline for future inspections.

Ambient conditions (air and steel temperature, relative humidity, dew point) are logged every shift.

Access, safety and site conditions

On a steel structure, access and safety often weigh more than the paint itself. They are settled at the survey.

• Access: lifts, scaffolding or rope access, depending on height, ground conditions and congestion.
• Work above running equipment: nets, tarps and protective decking to catch debris, abrasive and drips; coordination with production shifts.
• Overhead cranes: lockout of the crane and its power supply, stops on the runway, coordination with operators.
• Containment: temporary enclosures for abrasive and overspray, heated in winter when the product requires it.
• Old lead-based paint: common on older frames. It calls for testing before the quote and specific measures, handled by our lead paint removal service.
• Shutdown planning: what cannot be done in operation (hot areas, above sensitive lines, moving parts) is grouped into the shutdown, with our project management service when needed.

Pricing: by quote

Steel structure painting is priced by quote. The factors that drive it:

• The area and the shape of the members: a lattice takes longer than a solid beam.
• The condition of the existing paint and the share of full removal.
• Access: height, lifts, scaffolding, rope access, work above equipment.
• The system and the preparation grade.
• The work window: in operation, during a shutdown, at night, in winter.

Send photos, approximate dimensions and the location with your quote request: we reply within 24 business hours.

Where we work

Induscoat provides steel structure painting in Montreal, across Quebec and in Ontario, working from LaSalle:

• Montreal and Montérégie
• Quebec, for the province as a whole
• Abitibi-Témiscamingue
• Côte-Nord
• Saguenay–Lac-Saint-Jean
• Mauricie–Centre-du-Québec
• Ontario

When this service is not the right answer

Painting is not the right answer once the steel has lost section: deep pitting, thinned members, or attacked connections and welds. Paint protects what is left, it does not restore lost strength. We stop, show you the condition, and the repair goes through our maintenance and rehabilitation service before repainting.

For equipment, tanks and machinery rather than structures, our industrial painting service is the better fit.

Typical Problems We Solve

• Rust spreading at connections, welds and the base of columns
• Old paint flaking off structures above running production lines
• Uncertainty between spot repair, overcoat and full removal
• Older frames that may carry lead-based paint

What You Receive

• Condition survey by zone with rust rating to ISO 4628-3 or ASTM D610
• Technical quote stating the method by zone, the system coat by coat and access
• Dry film thickness readings per SSPC-PA 2 and ambient condition logs
• Close-out file with data sheets, batch numbers and before and after photos

Timeline

Standards & Certifications

• ISO 12944: corrosivity categories and paint system selection
• ISO 4628-3 and ASTM D610: rating of rusting on painted steel
• SSPC-SP 2, SP 3, SP 11, SP 6 and SP 10: surface preparation grades
• SSPC-PA 2: dry film thickness measurement

Industries We Serve

• Mining: concentrator buildings, conveyors and transfer towers
• Steel and metallurgy: crane runways, process buildings, stacks
• Energy: steel structures, towers and pipe racks
• Manufacturing and warehousing: building frames, mezzanines, walkways

Service FAQ

Technical guides

• Maintenance painting of steel structures
• ISO 12944: corrosivity categories and system selection
• Power tool cleaning: SSPC-SP 3, SP 11 and SP 15
• NACE No. 2 / SSPC-SP 10 surface preparation
• Dry film thickness: definition and measurement

Related applications

Concrete industrial use cases where this service is applied.