PVF2 Roof Refurbishment, Cut Edge Corrosion Treatment and Gutter Re-Coating — Large Office Building, Gateshead

D&D Coatings’ Northern team carried out a full PVF2 roof refurbishment at a large office building in Gateshead. This included full roof overcoating, cut edge corrosion treatment, lap joint sealing and a complete gutter system re-coating. This project report details the scope of work, the specialist systems and materials employed and the outcomes delivered. All from initial client engagement right through to manufacturer warranty sign-off by DriSilane.

Project Summary

Initial Client Engagement

The building management company responsible for the Gateshead office building approached D&D Coatings following a direct recommendation from their insurers. The insurers had advised that the protective envelope of the building be assessed by a suitably qualified and reputable surveying practice. Acting on that recommendation, the client carried out a web search to identify appropriate industrial painting contractors and we, D&D Coatings were shortlisted as a preferred candidate.

For building owners and asset managers, insurer-led recommendations of this nature are increasingly common. Insurers and risk assessors recognise that an ageing or deteriorating roof coating system represents a tangible liability — not only in terms of water ingress and internal damage, but also in relation to the long-term structural integrity of the roof substrate itself.

Engaging a specialist contractor at the earliest opportunity allows defects to be addressed before they escalate into more costly remedial works or, in serious cases, premature roof replacement! See Assessing Substrate Corrosion Under Insulation for additional information.

Pre-Contract Condition Survey

Following initial engagement, a detailed condition survey of the building envelope was carried out by D&D Coatings’ registered building surveyor associates. The survey followed a systematic inspection methodology, covering all external elements of the building — including vertical wall cladding, rainwater goods, fixings, lap joints, ridge and eaves details and the full extent of the roof plane.

While the external wall cladding and other vertical components of the building were found to be in a well-maintained condition, the survey identified that the PVF2 roof system had reached the end of its effective service life in several key respects. The report highlighted the following principal defects requiring remediation:

• Widespread cut edge corrosion at sheet end laps and gutter overhangs
• Pitting corrosion affecting multiple areas of the profiled steel roof sheets
• Coating degradation and UV-related breakdown of the original PVF2 factory finish
• Deterioration of the internal steel gutter system, with sealant failure at joints and downspout outlets
• General atmospheric contamination and biological soiling across the roof area

The survey findings were documented in a formal condition report, which formed the basis of D&D Coatings’ detailed specification and quotation for the remedial works.

Understanding PVF2 Roofing Systems

PVF2 — also known as PVDF or polyvinylidene fluoride — is a factory-applied, high-performance fluorocarbon coating system applied to profiled steel and aluminium roof and wall cladding sheets during manufacture. The coating is formulated from a 70% fluoropolymer resin and 30% acrylic polymer blend and offers outstanding resistance to UV radiation, acid rain, industrial atmospheric pollution and colour fade. These properties make PVF2 the premium factory finish of choice for commercial, industrial and institutional buildings throughout the United Kingdom.

However, even the most durable factory-applied coating systems have a finite service life. Prolonged exposure to ultraviolet radiation, thermal cycling, wind-driven rain and atmospheric pollutants causes gradual degradation of the fluoropolymer matrix. As the coating approaches the end of its effective lifespan, the factory finish loses its hydrophobic and corrosion-inhibiting properties — and the underlying steel substrate becomes increasingly vulnerable to oxidation.

The cut edges of profiled steel roof sheets are a particular area of vulnerability. Where sheets are cut to length during installation, the factory coating is absent from the exposed edge — leaving the bare steel substrate at the lap joint and gutter overhang fully exposed to rainwater and atmospheric moisture. Over time, this leads to the characteristic rust staining and progressive edge delamination known as cut edge corrosion. Left untreated, cut edge corrosion will migrate beneath the factory coating and, ultimately, compromise the structural integrity of the sheet.

PVF2 Roof Refurbishment — A Cost-Effective Alternative to Replacement

Where a PVF2 roof is exhibiting signs of age-related deterioration and corrosion, full roof replacement is not always the only or most cost-effective option. Provided the underlying steel substrate retains sufficient structural integrity and the extent of active corrosion can be treated, a properly specified and applied overcoating programme can restore the weatherproofing performance of the roof system for a further extended service period — at a fraction of the cost of full replacement!

Specialist on-site roof coating systems such as DriSilane ReTrim — which is a solvent-free hybrid polymer coating applied by trained and approved contractors — are specifically formulated to adhere to aged PVF2 substrates. This will deliver long-term protection against water ingress, UV degradation and further corrosion. The use of an approved applicator like ourselves ensures that the work is carried out to the manufacturer’s specification and that the completed installation qualifies for a formal manufacturer’s warranty.

Project Mobilisation

D&D Coatings’ detailed survey, specification and programme of works were signed off by our Managing Director Paul Drinkwater, submitted to the client and accepted without delay. The client expressed satisfaction with the clarity of the scope document, the transparency of the pricing and D&D Coatings’ straightforward approach to project delivery. The agreed contract price included the installation of scaffolding, full supply of all coating materials, specialist consumables and personal protective equipment — with no hidden additions or provisional sums.

The project team was mobilised under the direction of Project Director Gary Wright. The team was made up of three experienced coating technicians drawn from D&D Coatings’ Northern division. Prior to commencement of any works at height, the perimeter scaffolding installation was subjected to a formal inspection and sign-off by D&D Coatings’ Health and Safety Executive Craig Wilmore. This was in accordance with the requirements of the Work at Height Regulations 2005 and the company’s established safe systems of work. All plant, equipment, materials and personal protective equipment were confirmed on-site and in readiness before works started.

Roof and Gutter Wash Down

In accordance with D&D Coatings’ standard pre-treatment protocol, all works commenced with a thorough pressure wash of the complete roof area and gutter system. High-pressure washing was carried out using D&D Coatings’ Bimson Petrol-Powered Pressure Washer — a robust and reliable unit suited to the high-output demands of large commercial roof washing operations.

The wash down phase served several prep functions. It removed accumulated atmospheric contamination and industrial particulate soiling. Pressure washing eliminated biological growth — including algae, lichen and moss — that had established across the aged coating surface, dislodged loose, friable and flaking coating material, and cleared debris from within the steel gutter channels. This process exposed the full extent of the defects requiring treatment. Thorough surface cleanliness at this stage is a requirement for effective coating adhesion and long-term system performance. No primer or coating system can compensate for inadequate substrate preparation.

Surface Preparation and Corrosion Treatment

With the wash down complete and the roof surface allowed to dry, the D&D Coatings team undertook a comprehensive programme of mechanical surface preparation across the full extent of the roof area. This phase of the works was critical to the long-term performance of the overcoating system and was carried out with the rigour and attention to detail that specialist corrosion treatment demands.

The survey had identified numerous rust spots and areas of active pitting corrosion distributed across the profiled steel sheets. Each affected location was individually treated by grinding and wire brushing to remove all surface rust, corrosion products and loose or weakly adhering coating material — exposing the sound, clean steel substrate beneath. Additionally, all sheet end lap joints and gutter overhangs exhibiting cut edge corrosion were mechanically abraded to the same standard, ensuring that no active corrosion was permitted to remain beneath the new coating system.

This level of pre-treatment is non-negotiable in any specification that carries a manufacturer’s warranty. The integrity of the overcoating system is entirely dependent upon the quality of substrate preparation — and our D&D Coatings team applied the same systematic approach to every detail area, regardless of scale or accessibility.

Coating Application

Coating works followed the preparation phase in a logical and structured sequence, with each stage of the application programme building upon the last to deliver a fully continuous and warranted system.

Spot Priming with Everbuild Black Jack 902

All areas of bare steel exposed during the grinding and mechanical preparation phase were spot-primed using Everbuild Black Jack 902. This included each individual rust and pitting corrosion spot across the roof sheets, the exposed steel at all sheet cut edges and lap joints, all fixings and fastener heads and the complete internal gutter system — including gutter downspout outlets, gutter joint details and gutter edge returns.

Everbuild Black Jack 902 is a solvent-based bituminous primer and waterproofing compound with proven compatibility with metal substrates. It provides excellent adhesion to prepared steel surfaces and forms a tenacious, flexible and moisture-resistant base coat that inhibits further oxidation and prepares the substrate to receive the subsequent coating layers. Brush application was employed throughout the priming phase to ensure full coverage and penetration into surface irregularities, fixings and detail areas.

Lap Joint and Detail Sealing

With all priming works completed, the team carried out a comprehensive programme of lap joint sealing across the roof. All sheet-to-sheet overlaps, gutter joint connections, ridge capping joints, ventilation boxing and cowl flashings were sealed to ensure continuity of the waterproofing system at every transition and detail area. Attention to detail at this stage is crutial to the long-term performance of the overcoating system. Unsealed or poorly sealed lap joints are among the most common entry points for water ingress in commercial roofing. Any weakness at this stage would represent a significant hidden risk to the building owner.

DriSilane Roof Coat Full Roof Application

The principal coating phase comprised the application of one coat of DriSilane Roof Coat across the full extent of the prepared and primed roof area. DriSilane is a solvent-free hybrid polymer roof coating system, formulated specifically for application to aged metal and PVF2 roof substrates. It delivers a flexible, UV-stable and weather-resistant membrane that restores the long-term waterproofing performance of the roof and provides sustained resistance to the full range of atmospheric and environmental stresses that commercial roofs in the north of England are routinely exposed to.

In line with the manufacturer’s recommendation and specification, the DriSilane Roof Coat was applied by airless spray. Spray application when carried out by D&D Coatings’ experienced spray technicians, delivers a more uniform and consistent film build across the profiled geometry of a metal roof, rather than brush or roller methods alone. It also achieves greater coverage efficiency over large roof areas, ensuring that the full extent of the coating programme could be completed within the agreed programme whilst maintaining the film build standard required to qualify for manufacturer’s warranty.

Gutter Re-Coating — DriSilane ReTrim

In parallel with the roof coating programme, the complete steel gutter system was re-coated using DriSilane ReTrim, applied following the Everbuild Black Jack 902 primer coat. DriSilane ReTrim is a heavy-duty, solvent-free hybrid polymer coating system designed specifically for the protection and refurbishment of external steel and aluminium rainwater gutters. It provides a thick, seamless and flexible protective membrane that is highly resistant to standing water, UV exposure and thermal movement — the three primary mechanisms of deterioration in exposed steel gutter systems.

The ReTrim finishing coat was applied by brush to the complete internal and external faces of the steel box gutters, incorporating all gutter joint details, downspout outlets and gutter edge returns — producing a continuous, pinhole-free protective film across the full extent of the rainwater drainage system.

Risk Management and Programme Challenges

All commercial roofing projects involve an element of programme risk arising from weather conditions and site-specific operational constraints — and the Gateshead project was no exception. D&D Coatings’ project management approach is specifically designed to anticipate, mitigate and manage these risks without compromising the quality of the finished installation or the continuity of the client’s business operations.

The principal site-specific challenge at Gateshead concerned the spray application phase of the roof coating works. The office building’s car park — situated immediately adjacent to the building and beneath the roof perimeter — remained in active use throughout the contract period. To eliminate any risk of overspray contamination to vehicles, D&D Coatings scheduled all airless spray operations exclusively for weekend working, when car park occupancy was substantially reduced. This approach reflects D&D Coatings’ standard practice on occupied commercial sites — where the normal business operations of building occupants and tenants are given equal priority to the programme requirements of the coating works.

Weather conditions also presented the usual programme challenges associated with working at height in the north of England during the winter months. Periods of heavy rainfall and high wind speeds necessitated temporary suspension of works on several occasions. Coating operations were not resumed until ambient conditions — including temperature, relative humidity and wind speed — were within the manufacturer’s specified application parameters for both the DriSilane Roof Coat and ReTrim systems. This discipline, even though it presents challenges for our teams, is fundamental to the delivery of a warranted installation: applying any coating system outside its prescribed application conditions risks compromised adhesion, inadequate film build and premature system failure.

Manufacturer Inspection and Warranty Sign-Off

With all coating and sealing works completed and the access scaffolding retained in situ, a formal final inspection of the completed installation was conducted by a DriSilane-appointed inspection representative. The scaffolding was deliberately retained at this stage to allow the inspector full and unobstructed access to all areas of the roof and gutter system — ensuring that the inspection could be carried out to the same standard of coverage as the works themselves.

The inspection encompassed a comprehensive technical assessment of the completed coating system, including:

• Film build consistency across the full roof area
• Surface finish quality and system uniformity
• Continuity of the coating membrane across all detail areas — including ridge caps, lap joints, penetrations and ventilation details
• Integrity of the cut edge corrosion treatment at all sheet end laps and gutter overhangs
• Quality and completeness of the gutter re-coating works, including outlet and joint details

The installation was confirmed as compliant in all respects and the DriSilane Manufacturer’s Warranty was formally issued to the client upon completion of the inspection. The issue of a manufacturer’s warranty on a refurbished roof system represents a significant and tangible asset for any building owner or asset manager — providing documented third-party confirmation of the quality of the installation and a defined period of protection against system failure attributable to material or application defects.

Project Outcome

The Gateshead PVF2 roof refurbishment was completed on programme and to the client’s full satisfaction. All areas of cut edge corrosion and pitting corrosion were effectively arrested, the gutter system was restored to a fully waterproof and protected condition and the full roof area received a continuous, warranted coating finish — reinstating the weatherproofing performance of the building envelope for an extended service period.

The client confirmed their satisfaction with both the quality of the completed works and the professional conduct of the D&D Coatings team throughout the contract period. Receipt of the DriSilane Manufacturer’s Warranty — issued following the formal independent inspection — provided the client with documented assurance of the long-term performance of the installed system and a clear record for their asset management and insurance files.

This project is a further demonstration of D&D Coatings’ capability in delivering technically demanding PVF2 roof refurbishment programmes on occupied commercial sites — and of the value that a properly specified, professionally executed overcoating programme can deliver for building owners, asset managers and facilities teams facing the challenge of an ageing or deteriorating factory-applied roof coating system.