Technical Article

Leaking valley gutters are a common problem on industrial roofs

When refurbishment is required, two of the most widely used solutions are liquid applied gutter waterproofing systems and gutter liners.

Both can be effective, but each has advantages and limitations that should be considered before selecting the most appropriate solution.

Liquid Applied Gutter Waterproofing Systems

Liquid applied systems are installed directly onto the existing gutter surface to create a seamless waterproof membrane.

Benefits:
    •   Seamless finish with no joints or overlaps.
    •   Adheres directly to the existing substrate, so does not allow water to track underneath.
    •   Can accommodate complex gutter details and penetrations.
    •   Allows the condition of the existing gutter to be monitored.
    •   Generally adds very little weight to the roof structure.

Drawbacks:
    •   Surface preparation is critical for long-term performance.
    •   Application is weather-dependent and typically requires dry conditions.
    •   Low temperatures, rain, or high humidity can affect curing and installation quality.
    •   Severely corroded gutters may require repairs before coating can be applied.

Gutter Liners

Gutter liners are typically bespoke formed from a high performance membrane and installed within the existing gutter to create a new waterproof channel.

Benefits:
    •   Can often bridge over minor defects and corrosion in the existing gutter.
    •   Installation may be less affected by minor substrate imperfections.
    •   Provides an immediate physical barrier to water ingress.
    •   Suitable for heavily deteriorated gutters where coating systems may not be appropriate.

Drawbacks:
    •   Water can sometimes migrate beneath the liner if leaks develop elsewhere on the roof and track underneath the system.
    •   Hidden corrosion can continue within the original gutter structure.
    •   Damage beneath the liner may go undetected for long periods.
    •   Can reduce the gutter volume capacity
    •   Joints, seams, and termination details require careful installation and maintenance.

Which System Is Best?

The most suitable solution depends on the condition of the existing gutter and the objectives of the refurbishment project. Liquid applied waterproofing systems are often preferred where the gutter structure remains sound and a seamless, long-term waterproof membrane is required. Gutter liners can be beneficial where gutters have deteriorated significantly and additional protection is needed. A detailed roof survey should always be carried out to assess the condition of the gutters and identify the most appropriate refurbishment strategy.

Conclusion

Both liquid applied waterproofing systems and gutter liners can successfully extend the service life of industrial roof gutters. Liquid systems provide a seamless bonded membrane but require suitable weather conditions and thorough preparation. Gutter liners can offer an effective alternative for more heavily deteriorated gutters, although they can potentially allow water to track beneath the liner and conceal ongoing corrosion. Selecting the right solution requires a thorough assessment of the roof's condition and long-term maintenance requirements.

Talk to the Rooflock technical team today.