BLD/Roofing/TBT-BLD-020

Damp Proofing and Tanking

Building & Structural Works › Roofing › Damp Proofing and Tanking

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Damp proofing and tanking protect below-ground structures from water ingress using membranes, coatings, and drainage systems.
Tanking products include bituminous coatings, cementitious slurries, liquid-applied membranes, and sheet membranes.
Many tanking products contain solvents, bitumen, or chemical compounds that are hazardous to health when inhaled.
Application in enclosed basement areas creates high vapour concentrations requiring forced ventilation and RPE.
The COSHH Regulations 2002 require assessment of all tanking chemicals before application work begins.
Hot-applied tanking systems involving heated bitumen create burn hazards and flammable vapour risks.
Surface preparation using grinding, chasing, and grit blasting generates dust requiring extraction and RPE.
Tanking membranes must be applied to clean, dry surfaces — contamination causes adhesion failure and water ingress.
Working in confined basement spaces combines chemical exposure with restricted access and poor ventilation.
BS 8102 provides the UK code of practice for protection of below-ground structures against water from the ground.

Chemical exposure	Solvent-based tanking products cause respiratory damage and central nervous system effects in enclosed spaces.
Fire risk	Hot-applied bitumen and solvent-based products are flammable — fire risk is high in confined basement areas.
Legal compliance	COSHH 2002 requires exposure assessment and ventilation controls for all tanking chemical application work.

Don't

Complete a COSHH assessment for every tanking product before application work begins
Ensure forced mechanical ventilation is running in basements before starting application
Wear RPE with organic vapour cartridges when applying solvent-based tanking products
Provide fire extinguishers at the work location when using hot-applied or solvent-based systems
Monitor air quality in enclosed areas for VOCs and ensure levels remain below exposure limits
Prepare surfaces by removing contamination and ensuring they are clean and dry before application
Wear chemical-resistant gloves and coveralls to prevent skin contact with tanking chemicals
Allow adequate curing and ventilation time before follow-on trades enter tanked areas
Brief all workers on the chemical hazards and emergency procedures before each application
Inspect completed tanking for defects and carry out water testing where specified

DON'T apply solvent-based tanking products in basements without forced mechanical ventilation
DON'T work with tanking chemicals without RPE specified in the COSHH assessment
DON'T use naked flames or hot works near solvent-based tanking products during application
DON'T eat, drink, or smoke in areas where tanking chemicals are being applied or curing
DON'T allow other trades into freshly tanked areas until ventilation has cleared all vapours
DON'T apply tanking membranes to damp, dirty, or contaminated surfaces — adhesion will fail
DON'T heat bitumen beyond the manufacturer's recommended temperature during hot application
DON'T store tanking chemicals in basements overnight where vapours can accumulate
DON'T ignore headaches, dizziness, or nausea during application — these indicate overexposure
DON'T puncture completed tanking membranes with fixings without approved detail and repair

See also: Basement Waterproofing Safety | COSHH Awareness

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