What does a commercial roof survey cover in Stroud?

The first job is to establish what is on the roof and how far through its life it is. On a membrane we look at the seams, laps and any splits, blisters or loose areas, then check the surface for wear, particularly around plant and walkways. On built-up felt we look for cracking, ridging and open laps. On metal sheet we look at fixings, side laps and the cut edges, where corrosion tends to start. Our guide to planned roof maintenance explains how those same checks are repeated each year once a programme is in place.

Underneath the covering sit the insulation and the deck, and they matter as much as the surface. A deck that has softened or rusted will not hold a new covering, and wet insulation will not do its job. Where we can, we check from inside the building as well, looking for stained ceilings, daylight at the laps and condensation, which can be mistaken for a leak. Photographs are taken of everything noted, so the report shows the roof as it actually is, with each image tied to a position on the roof plan. That lets a contractor, an agent or a tenant's surveyor find the same spot later without a guided tour.

On a flat or low-pitched commercial roof, drainage is half the survey. Under BS 6229, as manufacturers describe it, a design fall of 1 in 40 is meant to leave 1 in 80 on the finished roof. We look for where water stands after rain: shallow ponds, stained patches, dirt lines and algae all point to a fall that is not working.

Then the outlets. We check each one, along with the gutters, parapet scuppers and downpipes, for blockages, leaf build-up and damage. A gutter set between two roofs, a box gutter, is a frequent source of leaks, and our page on box gutter leaks and linings goes into how they fail. Overflows are checked too, since a secondary outlet is what stops a blocked main one from flooding a unit.

Drainage faults are cheap to fix compared with the damage they cause, and a survey is often the first time anyone has looked at the outlets in years.

Water more often gets in at a junction than across the open roof. A survey walks every upstand, flashing, coping, pipe and cable penetration, expansion joint and abutment to a wall. These are the places where two materials meet and movement opens a gap. Mastic that has dried out, flashings that have lifted and open laps are all recorded with a photograph and a position on the plan.

Rooflights get their own look. Old rooflights in profiled sheet roofs tend to go brittle with age, so a roof that looks solid can hide panels that would give way under a person. We note which panels are fragile, which are cracked and which are crazed or discoloured. Replacement is covered in our page on replacing rooflights on an industrial roof, and the access rules sit in the guide to fragile roofs and safe access, which is worth reading before anyone goes up.

The report marks fragile areas clearly, so that anyone who goes on the roof afterwards, such as a plant engineer or a window cleaner, knows where not to step.

A roof survey is not an asbestos survey, but we note what we see. If sheets look like asbestos cement, the report says so, and the next step is a sample test and a plan before any work starts. Under HSE guidance, sheets that are weathered but whole can be taken off by careful handling without a licence, while badly broken sheets move the job into the notifiable group. Our page on asbestos cement roofs on commercial units sets out the options. MyBuilder's 2026 guide lists a basic asbestos survey at £50 and a fuller one at £200 to £245.

The survey also cannot see everything. We cannot tell the state of a structure hidden above a ceiling from the roof surface alone, and where something looks wrong, we say what further opening-up would be needed rather than guessing.

The report is what you keep. It lists the roof's make-up, the problems found with photographs and locations, and what each problem needs: patch, repair, overlay or replacement. It separates the urgent from the can-wait, so a landlord can budget and an agent can brief a tenant. A good report is also useful evidence if a lease dispute or an insurance claim follows.

MyBuilder's 2026 inspection guide gives a UK range of £150 to £500, with standard inspections at £150 to £250, drone surveys at £200 to £400 and thermal surveys at £300 to £500. A drone is useful on a roof too large or too fragile to walk, and thermal imaging can pick out wet insulation. Which method is right depends on the building.

Afterwards you receive a written quote that covers scaffold or access, stripping, materials, labour, waste and making good. A 10-year workmanship guarantee, again in writing, backs whatever work goes ahead. Our commercial roofing page has more on industrial units, offices and mills.