Bridge Waterproofing Application

Bridge deck waterproofing prevents water and de-icing salts from reaching and corroding the structural concrete.
Common systems include spray-applied liquid membranes, sheet membranes, and hot-applied mastic asphalt.
Many waterproofing products contain solvents, isocyanates, or hot bitumen that create serious COSHH hazards.
Surface preparation using shot blasting or scabbling generates high levels of silica dust and noise.
Bridge deck waterproofing is often applied with traffic management on live carriageways nearby.
Torch-applied and hot bitumen systems involve hot works permits and fire prevention measures.
Product application requires specific temperature and weather conditions — rain and low temperatures cause failure.
Primer coats are often highly flammable and must be allowed adequate flash-off time before overcoating.
Quality control including adhesion testing, thickness measurement, and defect inspection is critical.
Working at the edge of bridge decks requires fall protection, especially on multi-span viaducts.

Chemical exposure	Solvents, isocyanates, and hot bitumen fumes cause respiratory sensitisation, burns, and long-term lung disease.
Fire hazard	Flammable primers and torch-on membranes on a bridge deck with limited escape routes create serious fire risk.
Structural protection	Failed waterproofing allows water and chloride ingress that causes reinforcement corrosion and structural deterioration.

Do

Don't

Complete a COSHH assessment for all primers, membranes, and waterproofing products
Wear RPE, chemical gloves, and eye protection during all application operations
Obtain a hot works permit before using torch-on or hot-applied membrane systems
Allow primer coats adequate flash-off time before applying the next layer
Provide fire extinguishers at the work location throughout hot works activities
Ensure dust suppression and RPE are used during shot blasting or scabbling
Install edge protection at bridge deck perimeters before starting any work
Check weather conditions — apply only within the manufacturer specified temperature range
Test adhesion and thickness of the finished membrane before allowing surfacing
Brief the team on chemical hazards, fire risks, and emergency procedures daily

DON'T apply waterproofing products without completing the COSHH assessment first
DON'T use torch-on systems without a hot works permit and fire watch
DON'T apply membranes in wet conditions or outside the temperature specification
DON'T allow smoking or naked flames near flammable primer application areas
DON'T work at bridge deck edges without guardrails or fall arrest systems
DON'T skip surface preparation — poor preparation causes membrane adhesion failure
DON'T ignore skin contact with primers or resins — wash immediately and seek advice
DON'T overcoat primers before the required flash-off time has elapsed
DON'T carry out shot blasting without silica dust controls and hearing protection
DON'T allow traffic onto the finished membrane before it has fully cured

See also: Bridge Construction Safety Awareness | Bitumen and Tar Products

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