Ely Roofers carries out commercial roofing across Histon, and we know that for most building owners, understanding the likely cost is the first thing they want to get clear.
Commercial roofing costs vary considerably, and any contractor who gives you a firm price over the phone without seeing the roof is guessing. That said, having a realistic sense of the typical ranges before you call anyone puts you in a stronger position. The figures below reflect typical current UK rates for commercial work. Every job is different, and a site survey is always needed for an accurate price.
As a rough starting point: flat roof replacement using a single-ply membrane or EPDM on a commercial building typically costs between £70 and £130 per square metre, including materials, labour, removal of the old covering and perimeter detailing. Built-up felt systems are generally at the lower end of that range. Profiled metal sheet re-roofing on a warehouse or agricultural building typically falls between £25 and £60 per square metre for the sheeting alone, with the total cost depending heavily on whether the existing structure and purlins are sound.
These are indicative figures. The actual cost of your roof in Histon will depend on a set of specific factors, each of which is explained below.
The most obvious cost driver is size. Larger roofs cost more in total but are generally cheaper per square metre because the fixed costs - scaffolding, plant hire, materials delivery, set-up and break-down time - are spread over a greater area. A 500 square metre roof will cost significantly more overall than a 100 square metre one, but the rate per square metre tends to fall as the area increases.
Measuring a commercial roof accurately requires being on it. Satellite measurements and ground-level estimates are frequently wrong, particularly on roofs with rooflights, plant rooms, varying levels or complex perimeter shapes. Always base your budget planning on a measured survey.
The deck condition is one of the biggest unknowns before a survey and one of the most significant cost variables. If the existing deck - whether it is timber boarding, concrete, metal decking or a screed - is sound, the new roofing system can go straight on (or the old covering stripped and replaced). If the deck is damaged, wet, rotten or structurally compromised, those repairs must come first.
Wet insulation discovered during strip-off also adds to the cost. Saturated insulation boards cannot be left in place - they add dead weight, provide no thermal value and create a reservoir of moisture beneath the new covering. Replacing insulation on a large roof can add £15 to £40 per square metre to the total, depending on the specification.
This is why it is genuinely not possible to give a reliable price without inspecting the roof. A survey that uncovers a compromised deck early saves the client from the worse scenario: discovering the problem after the new membrane is half-installed.
Different materials have different costs, and the gap between the cheapest and most expensive options is significant. As a general guide:
The right system is not always the cheapest one upfront. For a building you plan to own for 20 years, paying a modest premium for a longer-lasting system often works out cheaper in the long run than replacing a felt roof twice in the same period.
Access to the roof has a direct cost implication. A single-storey building with clear, level ground around it is the easiest scenario. Costs increase with:
A flat roof without adequate falls will pond water, and ponding water shortens the life of any roofing system. Where the falls on an existing roof are poor, the most effective solution is tapered insulation - boards cut to a slope that directs water to the outlets. Tapered insulation adds material cost and takes longer to install than flat boards, but it is the correct long-term solution.
Outlets themselves are often in poor condition on older roofs - blocked, corroded, or simply undersized for the roof area they are meant to drain. Replacing outlets is not expensive in isolation, but it requires the surrounding membrane to be cut back and re-detailed, which is additional labour.
On some commercial roofs, particularly metal sheet buildings, it is possible to lay new sheeting over the existing covering rather than stripping it first. This is sometimes called over-roofing or over-cladding. It is faster and creates less waste, which can reduce cost - but it is only appropriate where the existing structure can carry the additional load and where the existing deck is not wet or structurally compromised.
For flat roofs, over-roofing with a new membrane is possible in some circumstances but is not appropriate where the existing deck is damaged or where moisture is already trapped beneath the old covering. Burying wet insulation under a new membrane simply creates a larger problem for later.
The only reliable way to know what your commercial roof will cost is a survey followed by a written, itemised quote. A quote that just says "flat roof replacement - £X" without breaking down the scope gives you very little information and leaves you exposed to disputes or additions later.
When comparing quotes from different contractors, make sure you are comparing the same scope. A lower price that excludes deck repairs, outlet replacement or proper perimeter detailing is not genuinely cheaper - it is incomplete.
We will assess the roof properly, explain what we find and give you a written quote that sets out exactly what is included.
No obligation · We usually respond within 2 hours
Storm damage, active leak, damaged ridge - we aim to be on-site within 24 hours.
