Ventilation duct coating and sealing
Refurbish ducts from within – preserve existing structures
TKR coating can seal duct leaks, reduce the entry of contaminants into indoor air and prevent condensation from leaking into surrounding structures. Suitability is assessed based on the condition of the ductwork and the repairs needed.
- Two coats in different coloursThe colour contrast helps verify coverage
- Camera monitoring throughoutApplication is monitored from inside the duct
- Pressure testing when requiredAirtightness is checked as agreed
When should you consider coating?
Sound ductwork may be worth keeping
Internal coating or local sealing is worth considering when the ductwork can be retained and the repairs concern airtightness or the internal surface.
- Duct airtightnessLeaks make ventilation harder to balance and can increase energy losses. Sealing helps control airflow.
- Fibre problemsFibres released from duct surfaces or carried through leaks can enter indoor air. The repair approach depends on the source of the fibres.
- Internal surface durabilityThe elastic coating withstands duct vibration and routine mechanical cleaning.
- Corrosion resistanceThe coating protects the surface against corrosion. Suitability for chlorine-exposed, industrial and marine environments is confirmed for each project.
Video in Finnish.
The method in practice
From a clean duct to a sealed surface
Dust and grease are removed before coating. TKR Gel 2 is applied in two coats, each in a different colour. The colour contrast makes coverage easier to check, and the application is monitored by camera throughout.
The entire duct can be coated, or treatment can be limited to leaks and seams. Full coating in accordance with TKR’s method instructions makes the duct airtight, watertight and antistatic. The coated duct withstands routine cleaning.
- Reducing air leakage and the resulting energy losses
- Preventing fibres and dust from passing through sealed areas
- Preventing condensation from leaking into surrounding structures
- Less demolition when existing structures can be retained
Every project is different
Confirm suitability before work begins
The repair method and coating are selected based on the condition and materials of the ductwork, the problems identified and the operating conditions.
Full coatingThe entire internal surface of the duct is treated to form a continuous, airtight and watertight coating.
Local sealingTreatment is limited to leaks and seams. TKR’s instructions specify extending the coating 100 mm on either side.
TKR duct liningFor complex or extensive breaks, TKR duct lining can be assessed as a repair option. The method uses a shaped liner impregnated with TKR coating.
Antibacterial coatingTKR also offers an antibacterial coating for applications requiring hygienic surfaces. Suitability for use inside ventilation ducts is confirmed separately.
Potential applications
- steel ducts and ducts formed from building materials, such as brick
- structurally sound ductwork that can be retained
- localised leaks or internal surfaces requiring treatment
- hard-to-access structures or protected heritage features
What needs to be assessed?
- materials, damage and whether the duct can be cleaned
- hazardous substances and required qualifications
- chemical exposure, operating conditions and fire safety requirements
- service interruptions and quality assurance
- 01Assess
Duct condition, materials and repair needs.
- 02Plan
Repair method and quality assurance.
- 03Clean
Remove dust and grease from the duct surface.
- 04Coat
Two coats in different colours.
- 05Verify
Camera inspection and pressure testing when required.
Case study
Preserving original structures at Finlandia Hall
The ducts and associated shafts were inspected, cleaned and coated in collaboration with an asbestos contractor. Air sampling verified cleanliness. The solution allowed the original marble surfaces to be preserved.
Key method details
- Coating
- Two-component TKR Gel 2
- Coats
- Two coats in different colours, total thickness 0.5 mm
- Application
- Rotating spray head or targeted spraying; manual application with a brush or roller
- Finished surface
- When fully coated: airtight, watertight, antistatic and resistant to cleaning
- Inspection
- Camera monitoring and pressure testing when required
- Training
- TKR offers material and equipment training for installers
Product data sheet and work stages
Visit TKR’s product data sheets page (in Finnish) and download the ventilation duct coating sheet to support your planning.
Frequently asked questions
Your questions answered
When the ductwork can be retained and the repairs concern leaks or the internal surface. Suitability is confirmed through duct inspections and an assessment of the project requirements.
According to TKR, the method is also suitable for ducts containing asbestos. Suitability, working arrangements and cleanliness checks are planned for each project. At Finlandia Hall, the work was carried out in collaboration with an asbestos contractor.
Coverage is checked using the contrast between the two coating colours. Application is monitored by camera throughout, and airtightness is checked with a pressure test when required.
Yes. According to TKR’s method instructions, coated ducts can undergo routine cleaning without needing to renew the coating.
The next step
Find the right repair method for your ductwork
Tell us the building type, duct material and problems you have identified. A TKR specialist will help assess whether the method is suitable and advise on the next steps.