Industrial Roof Coating FAQs
We have produced this FAQ page to help specifiers and contractors with instant answers.
We are also available by telephone on 0121 709 5352 between 9:00am and 5pm weekdays to answer any questions personally.
Metal Roof Coatings
Liquasil provides two metal roof coatings, Metalseal and Liquasil Lite.
Metalseal is usually the specifiers choice since it has BBA Approval.
Liquasil Lite is for use where budget is paramount. This is fire rated to Broof(t4)
Asbestos Roof Coatings
Our Asbestoseal system was the first purpose-made asbestos roof coating to gain BBA Approval.
We dropped this accreditation in 2024 because in many cases, clients prefer to replace the roof and increase the thermal performance.
Gutter Liners
Liquasil’s liquid gutter lining system is called “Gutterseal” comprising 3 components.
A liquid gutter liner has many advantages over certain types of physical liners, but it’s important to understand the differences.
General
Liquasil’s range of silicone roof coatings are formulated exclusively by us.
Made in the UK to exacting standards, you can be certain that they perform like no other coating systems.
Our team is made up of specialist surveyors, not sales people.
Metal Roof Coating Questions
How Long Do Roof Coatings Last?
Service life depends on the system, preparation and environment, but in general:
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Silicone roof coatings – typically designed for 25 year service lives when correctly specified and installed
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Liquid gutter liners – commonly aligned with 15+ year refurbishment expectations
We always distinguish between “paint job” coatings and fully specified systems. Liquasil’s systems sit firmly in the latter category.
For system-specific information, see our metal roof coating and liquid gutter liner pages.
Can I Coat Over Plastisol?
Our metal roof coatings have been designed for use on aged Plastisol coated metal roof sheets, because they are most commonly used on UK industrial roofs.
Plastisol degrades over time and will first fade, then begin to craze and crack before completely delaminating from the galvanised substrate.
It is important to understand that if the Plastisol has degraded to the point where the surface is becoming crazed, that it may come away from the surface as the roof is being pressure washed.
If this does start to happen, it will need to be removed as far as is reasonably practicable before over-coating, because new coatings do not stick down old finishes.
Liquasil will normally recommend a site inspection or at least adhesion tests before specifying over-coating of other types of finishes. More detail is available on the metal roof coating page.
What is a Protective Coating?
A metal roof coating is classed as a protective coating, meaning that it provides protection to the metal substrate to;
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Control corrosion at sheet edges, laps and fixings
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Extend the useful life of the roof without changing the underlying structure
- Provide protection against UV damage
- Repel & resist water
Liquasil’s metal roof systems are silicone-based and were designed by building surveyors specifically for industrial metal roofs.
What About Solar Panels?
We are often asked if metal roofs should be coated before installing solar panels and often, it is best practice.
This is because solar companies provide long-term guarantees on their installations and will often insist that roofs are brought into repair prior to the panels being installed.
This is because removing and refixing solar panels to attend to roof maintenance is very expensive and could invalidate a guarantee.
If the metal roof surface is already degraded, it will only worsen with time, so it’s best to treat cut edge corrosion as a minimum, but also consider a full metal roof coating before installing solar panels.
We discuss this in more detail on the metal roof coating page and in our guidance for solar projects.
What Is BBA Approval For?
BBA certification gives specifiers an independent assessment of performance, durability and suitability when coating metal roofs. You’ll find more detail on the metal roof coating page and in our BBA certificates.
Liquasil’s Metalseal system was the first specialist metal roof coating to achieve BBA Approval in the UK and our Flexlap system was the first stand-alone cut edge corrosion treatment.
BBA Approval comes at a heavy cost and this is factored into the price. If you need a more budget-friendly option, we offer our Liquasil Lite metal roof coating which does not have BBA approval, but is fire rated to Broof(t4).
How Does Liquasil Compare?
There are only a few companies that offer a BBA Approved metal roof coating suitable for use by professional specifiers.
When discussing comparisons with competing systems, there are two main things to consider:
- Performance
- Cost
Liquasil’s silicone roof coatings are designed to last and have been designed by building surveyors to meet the exacting needs of specifiers.
Our products match and often exceed the performance of those avaiable from our competitors, but usually at a significantly lower price point.
Because our systems are single-coat application, labour costs are lower.
If you don’t require BBA Approval, our Liquasil Lite roof coating is very competitively priced against newer, unproven roof coatings, but with better performance and the proven support of the qualified Liquasil team.
Cleaning & Preparation Questions
Should I clean the roof before coating?
Yes. Correct and thorough cleaning is essential for any coating system. It removes:
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Dirt and loose & flaking materials
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Moss, algae and other biological growth
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Contaminants that would otherwise prevent adhesion
The roof also needs to be dry before primers and coatings are applied. Our metal roof cleaning guide sets out the key steps.
Can I just pressure-wash a metal roof?
Roof cleaning should be factored into a planned and preventative maintenance program in any event and has the advantage that any defects that are beginning to appear, can be identified dealt with quickly.
Bear in mind that aggressive jet washing should be avoided if you suspect that the existing finish is unstable, as this will remove the finish, though if that’s the case, the roof is in need of recoating.
Your need for a roof coating is usually determined by factors such as dilapidations claims, new tanancy agreements and building refurbishment.
Does cleaning alone extend roof life?
Cleaning a metal roof certainly helps to removing corrosive deposits and biological growth that trap moisture, but it does not replace proper defect repair and coating.
In many refurbishments, cleaning is the first step, followed by targeted repairs and then a full coating system.
Industrial Gutter Lining Questions
Why are industrial gutters problematic?
The simple answer is that it’s usually due to the sheer size of industrial roofs and the amount of water that is collected by them.
Gutters tend to collect a lot more silt and organic matter because often, gulls and other birds are nesting on the roof, so the roofs become heavily soiled and this washes into the gutters during rainfall.
Metal gutters are also affected by thermal movement and this can cause the seals at the gutter joints to fail.
What is Liquasil Gutterseal?
Gutterseal is Liquasil’s liquid gutter lining system. It uses:
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SWT Primer – to stabilise and prevent corrosion on metal surfaces
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Non-Sag Sealer – to seal joints, fixings and local defects
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Liquasil One – to create a fully bonded, seamless gutter liner
This is explained in more depth on the liquid gutter liner page.
Do I need a physical or a liquid gutter liner?
A physical liner introduces a new gutter inside the existing gutter, usually with clips and joints.
A liquid liner bonds directly to the existing substrate and becomes part of it, with no mechanical joints to maintain.
The right choice depends on gutter design, condition and project constraints.
Liquasil can advise which is more appropriate based on survey information but usually where the gutter is very heavily rusted and perforated, a physical liner is probably more appropriate.
If a gutter is more complex, containing numerous angles or if access is limited, a liquid lining is probably recommended.
Specifications, Warranties & Projects
Can I specify Liquasil products for dilapidations?
Yes. Our products and systems were created to meet the expectations of dilapidations surveyors.
The Liquasil team was formed out of a building surveying practice, so we know dilapidations better than any other coatings manufacturer.
Did you know that Liquasil has presented metal roofing and cut edge corrosion CPD sessions for an on behalf of The Royal Institution of Chartered Surveyors?
Our metal roof coating and liquid gutter liner pages cover typical use cases.
Are Liquasil products guaranteed?
Liquasil systems are supplied with product warranties when they are installed:
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In accordance with an agreed Liquasil specification, and
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By suitably trained and approved contractors
Metal roof systems typically offer 20–25 year product warranties, while liquid gutter linings typically offer 15 years. Project-specific terms are confirmed in writing.
Can I get a project-specific roof coating specification?
You can email survey reports, photographs and basic project information to Liquasil, and we’ll provide a project-specific specification based on the roof construction, condition and client requirements.
Photographs need to be high quality and contain close-ups of defects and the substrate condition.
Site Inspections
Our team of roofing surveyors is able to attend site visits to support surveyors and building owners considering specifying Liquasil products on refurbishment projects.
Dilapidations inspections are excluded from our free survey service, but we are able to assist for a standard roof survey fee. Please ask for details.