Commercial roofing quotes: FAQs

Because they are rarely quoting the same scope. One firm strips a wet deck and rebuilds a warm deck to a Part L U-value with a 25-year single-point manufacturer guarantee; another overlays the existing roof, leaves the condensation problem in place, and offers a workmanship promise. The headline numbers look comparable and the work behind them is not. Ask every quote for the system, the build-up, the falls design, the guarantee type and term, and what it excludes, then you are comparing like with like.

As an indicative guide, supplied and fitted: industrial re-cladding around £70 to £140/m², commercial flat-roof re-roofs around £90 to £180/m², pitched re-roofs around £90 to £220/m², overlay and over-roofing around £45 to £110/m², and life-extending coatings around £20 to £55/m². Gutter lining is priced per linear metre. The real driver is the build-up the deck, falls and loads demand, not the headline material, so a defensible number comes from a survey, not a rule of thumb.

Repair where the failure is localised and the deck, insulation and falls are otherwise sound. Refurbish — overlay, over-clad or coat — where the substrate is sound and dry but the covering is tired, and you want to defer capital cost honestly. Replace where the insulation is wet, the roof ponds because it was never laid to fall, the deck is failing, or reactive patching has become an annual cost that never fixes the fault. The honest test is whole-life cost, and a proper survey gives you all three numbers.

A survey-based specification, not just a rate: the existing build-up and deck type, the system proposed and why, the falls and drainage design (to BS 6229:2025 on a flat roof), the U-value and whether a Part L upgrade is triggered, the guarantee type and term, the access and safety plan for working at height over a live building, the phasing, and a clear list of what is included and excluded. If a quote is a single rate per square metre with none of this, it cannot be compared or defended.

Often yes, but only after a survey confirms the roof can take the load and has enough life left to justify it. A ballasted or fixed array adds roughly 15 to 25 kg/m² of dead load in typical conditions — more, up to around 30 kg/m², on exposed or high-wind roofs — plus wind uplift, and it sits on the roof for 25 years or more. Putting an array on a tired roof means lifting it again to re-roof underneath within a few years, so where solar is planned the right sequence is to survey and, if needed, re-roof first.

In the general case, no. Commercial roofing is capital works and planned maintenance, and there is no public grant scheme that pays to re-roof a commercial building. Any site advertising a 'roofing grant' should be treated with caution. The legitimate financial angles are tax treatment, 20% VAT that a VAT-registered business recovers, and capital allowances on the insulation element of a warm-deck or insulated-panel upgrade — all matters for your accountant.

Usually yes, for anything beyond a minor repair. Re-covering more than 50% of the roof surface, or renovating more than 25% of the whole building envelope, is notifiable and triggers a Part L thermal-element upgrade. Where your installer is CompetentRoofer-registered, the work can be self-certified and a Building Regulations Compliance Certificate issued for your records instead of a separate Local Authority Building Control application.

Over-roofing lays a new covering over the existing one — over-sheeting a profiled metal roof, or overlaying a sound flat roof — without a full strip. It is faster, cheaper and less disruptive, and it keeps waste out of landfill. It is honest only where the substrate is sound and dry and the structure can take the added load. Over an already-wet or condensation-damaged roof it simply hides the fault, so it must be a survey decision, never a default.

On a large profiled-metal roof the most common source of an unexplained internal leak is not the sheets but the gutters — failed valley or box-gutter joints, laps and outlets — and cut-edge corrosion at the sheet ends. Both are far cheaper to put right than a re-clad. A gutter lining or cut-edge treatment often solves a leak that has defeated repeated sheet repairs, which is exactly why a survey looks at the whole roof, not just the reported drip.

Less than most owners fear, when it is planned properly. Most commercial roofs are re-covered bay by bay while the building stays operational below, with the noisier work phased to holidays, evenings or quiet periods. Working at height over a live building is managed under the Work at Height Regulations 2005 with edge protection, fragile-roof precautions and a rescue plan. A good quote sets out the phasing and the plan for keeping you trading.

The guarantee to ask about is a single-point or insurer-backed manufacturer guarantee, issued because a manufacturer-approved installer fitted the system to specification. It covers materials and workmanship for a defined term — commonly 20 to 30 years on a flat roof, longer on cladding. Ask for the number of years, exactly what is covered, and whether the cover survives any one firm ceasing to trade. Never accept anything described as a lifetime guarantee, because a guarantee is always bounded by a term.

It depends on the system and how well it was installed. A single-ply or reinforced-bitumen warm-deck flat roof runs around 25 to 35 years; a new insulated metal or composite cladding system 30 to 40; a pitched slate or tile roof 40 to 60. A coating extends a sound metal roof by 10 to 20 years without upgrading it. The guarantee term is a separate, shorter figure, and the two should never be confused.

We connect you with a surveyor who assesses the roof and sets out repair, refurbishment and replacement options with honest costs and remaining-life estimates. Send the building type, the roof size and what the roof is doing now through the quote form, and we respond within one working day. There is no obligation and no site visit is needed for an initial view.

Any commercial building from before 2000 must be surveyed for asbestos before intrusive roof work under the Control of Asbestos Regulations 2012. Legacy asbestos-cement sheets and rooflights, asbestos insulating board at soffits and upstands, and some old bitumen products can contain asbestos. Where present it is managed, and where required removed, by a licensed contractor — it is designed into the programme, not discovered halfway through.