Recurring leaks
Water entering at laps, fixings, details, rooflights, gutters or the field membrane.
Commercial roof overlays
Commercial roof overlays.For suitable existing roofs.
Large-scale liquid and spray-applied overlays that retain suitable existing roof fabric, rebuild waterproofing continuity and reduce disruptive strip-up.
The commercial case
An overlay is not a shortcut around diagnosis. It is a designed refurbishment route for a roof whose retained substrate, moisture condition, drainage and details have been proven suitable.
When overlay enters the conversation
An existing roof may be suitable for an overlay.
Aged waterproofing
An existing covering approaching the end of its reliable service window.
Complex penetrations
Plant, kerbs, outlets and interfaces that make wholesale strip-up disruptive.
Operational pressure
Warehousing, production, education or retail space that needs the building kept working.
Overlay systems
Choose the overlay system from the roof condition.
01
Scale + complex profiles
SprayGrade liquid rubber
Two-component water-based spray membrane for suitable large roof areas and asbestos-cement encapsulation. Manufacturer-backed warranty routes may be available on qualifying projects, with the applicable terms confirmed in writing.
02
Rapid specialist application
HotSpray pure polyurea
Highly reactive, solvent-free aromatic pure polyurea for suitable new and refurbishment roofs, delivered with specialist heated plural-component equipment.
03
Details + controlled phasing
MonoSeal hand-applied polyurea
Hand-applied pure-polyurea waterproofing for complex details, transitions and roof zones where spray application is not suitable.
04
Familiar refurbishment route
Reinforced liquid overlay
Hand- or roller-applied reinforced systems where geometry, detailing density, access or project phasing supports a liquid-applied specification.
The overlay decision
Five checks before installation.
01
Prove the substrate
Identify the existing roof, moisture, adhesion, movement and structural constraints.
02
Remove false economy
Separate defects that can be repaired from conditions that make overlay unsuitable.
03
Compare technologies
Test application method, chemistry, detailing, programme, weather and access against the project.
04
Design every interface
Build laps, fixings, kerbs, outlets, rooflights, edges and gutters into the scope.
05
Install + record
Control preparation, weather, membrane build, inspection and handover evidence.
Warehousing
Manufacturing
Schools
Retail + FM
Clear answers
Commercial roof overlay questions
Suitability, technology selection, asbestos and occupied-building delivery
What is a commercial roof overlay?
A commercial roof overlay retains suitable existing roof fabric and adds a compatible waterproofing system above it. It is a designed refurbishment route, not permission to cover wet insulation, unstable substrates or unresolved structural defects.
Can every commercial roof be overlaid?
No. Substrate stability, trapped moisture, adhesion, drainage, deck condition, existing layers, details, fire requirements and structural capacity must support the proposed build-up.
Which overlay system is best?
There is no universal best system. SprayGrade, HotSpray polyurea, MonoSeal and reinforced liquid systems use different chemistry and application methods. Scale, substrate, geometry, access, weather, occupied-building constraints and the required tested build-up determine the sensible route.
Can an asbestos-cement roof be overlaid or encapsulated?
Sometimes, after asbestos information, sheet condition, fragility, structural support and work classification have been assessed. Suitable roofs may follow a controlled repair and encapsulation route; severely damaged material may require local replacement or removal.
Will the building need to close during an overlay?
Not always. Many overlays are planned around occupied buildings, but access, exclusion zones, odour, noise, overspray risk, internal sensitivity and the work method determine what can remain operational.
Is overlay cheaper than roof replacement?
It can reduce strip-up, disposal and disruption where the retained roof is genuinely suitable. A low initial price is not a saving if moisture, poor drainage or an unstable substrate is simply concealed.
What information is needed for an initial assessment?
Useful information includes the roof type, approximate area, postcode, photographs, known leak locations, previous repairs, building use, asbestos records where relevant and any existing survey or specification.
Commercial overlay assessment