Most commercial roofs do not fail in a dramatic way. A blocked outlet lets a puddle build behind a parapet for a season, a sealant bead dries out along a lap, a fixing works loose in a gale, and eventually water finds a way in above the stock or the server room. Each of those faults is cheap to deal with early and expensive to deal with late. Planned maintenance is simply the habit of looking before the water does. This guide explains what a visit involves on the roofs we see around Basingstoke, what we clear, tighten and reseal, what we leave alone, and what paperwork you should end up with.
What planned maintenance actually is
Planned maintenance is a set of scheduled visits, usually in spring and autumn, where someone who understands the roof walks it, photographs it and fixes the small things on the spot. It is different from a repair call, which starts after water has arrived, and different from a full condition survey, which is a one-off report on the state of the whole roof ahead of a big decision. A good visit sits between the two. It catches wear while it is still wear, and it records enough that the next visitor, and the next owner, can see what changed.
It also protects the people who depend on the roof. A facilities manager answers to a landlord, a landlord answers to a tenant, and a tenant answers to whoever owns the goods under the roof. A dated record of visits, with photographs and a note of what was done, is the simplest way to show that the roof was looked after. If you are unsure who carries the repair duty under your lease, our page on landlord or tenant roof repairs sets out how that usually divides.
The visit is not a licence to spend. We tell you what is routine, what is worth watching and what needs a proper repair, and we separate the three in the write-up so you can budget. If the roof still has a good life ahead, the report states that plainly.
Drainage first: outlets, gutters and parapets
If we could only check one thing on a commercial roof, it would be where the water leaves. Flat roofs on shops, offices and units shed rain through outlets, which are the drain points set into the surface, into box gutters (lined channels that run along a parapet or between two roof slopes) and over eaves into gutters. Every one of these can silt up. Leaves, moss, feathers, windblown plastic and the grit that washes out of an ageing surface all collect at the lowest point and start to hold water.
Standing water is the quiet enemy of a flat roof. It adds weight, it carries dirt and algae that attack the surface, and in winter it freezes and lifts edges and laps. On a built-up felt roof it speeds up the breakdown of the top layer. On a single-ply roof it sits on seams, which are the strongest part of the sheet when new but the first place to open if the weld was poor or the water is persistent. We clear the outlets by hand, lift any grating, check that the pipe below is running, and look at whether the water is leaving or merely thinning out.
Parapets and box gutters deserve a second look. A parapet is the low wall that rises above the roof edge, and it is capped with a coping stone or a metal capping to keep water out of the brickwork. When a coping joint opens or a capping lifts, water runs down the inside of the wall and appears as a damp patch on an upper floor far from the roof edge. A box gutter that is too shallow, or one whose lining has split along its length, can overflow into the building with no sign on the main roof at all. We check the lining, the outlet size and the overflow, which is a smaller opening set higher than the main outlet so that a blocked drain shows itself outside the building rather than inside.
Metal sheeted roofs: laps, fixings and cut edges
Warehouses and industrial units usually have profiled metal sheets or composite panels (two metal skins with an insulating core) fixed to steel purlins, the horizontal beams that carry the roof. The sheets overlap along their sides and ends, and those overlaps, known as laps, are sealed with a mastic strip or bead that dries and shrinks over the years. A visit looks at every line of laps that can be reached safely, noting where the seal has opened, where a sheet has lifted and where a fixing has gone missing.
Fixings matter more than they look. Each screw carries a washer that compresses against the sheet to seal the hole. With temperature swings and wind the sheet moves slightly, and over time a washer can crack, a screw can back out, or a hole can elongate. A gale makes that worse. We replace failed fixings with the right type for the sheet and the steel beneath, and we reseal rather than simply tighten, because an over-tightened screw crushes the washer and leaks sooner than a loose one.
The other long-term issue on steel sheeting is corrosion that starts where the coating has been cut. A sheet is galvanised and then coated, but wherever it was cut to length or drilled, bare steel is exposed at the edge, and rust creeps in under the coating from there. You see it as orange staining along laps and at the bottom edge of sheets, and in wet spots under overlaps and in valley gutters. Our guide to cut edge corrosion on metal roofs covers the causes and the treatment options. At a maintenance visit we look for the early signs, clean back and treat small areas, and record the ones that are spreading so you can plan sheet replacement rather than be surprised by it.
Rooflights are the last item on a sheeted roof. Old translucent sheets of GRP (glass-reinforced plastic) go brittle and chalky in sunlight, and a sheet that looks solid can break under a person's weight. We treat every rooflight as fragile until shown otherwise, and our notes on fragile roofs and safe access explain the rules that apply when anyone goes onto the roof, whether a roofer, a solar installer or your own maintenance staff.
Single-ply and felt roofs: seams, upstands and surface wear
Single-ply is a factory-made sheet of synthetic membrane, laid across the roof in strips and joined along the edges by heat welding or adhesive. Built-up felt is made of two or more bitumen layers laid on site, finished with a cap sheet that is often covered in mineral granules. They behave differently, so the visit looks at different things.
On single-ply we walk the seams, press along them to check that they are bonded, and look at the corners and the upstands, the parts of the membrane turned up a wall, a plant plinth or a rooflight kerb. Upstands fail by slipping down the wall when their top edge is not held, or by splitting where the membrane was stretched round a corner. We check the termination bar or sealant at the top of each one, and we look at the membrane around every penetration, where a pipe, cable or support leg passes through the roof. Penetrations are where later trades cause damage, so a visit after any plant installation is worth far more than the usual interval.
On felt we look for blistering, which shows as raised domes where moisture or air is trapped, for cracking and for the splits that open along old laps. The mineral granules on a cap sheet are there to shield the bitumen from sunlight, so we look at where they have worn away, usually along walkways and below outlets. Small blisters can often be left under observation. Open splits and lifted laps are repaired, because water behind a felt layer spreads sideways along the layers and appears a long way from the source.
Both kinds of roof carry hidden risk below the surface. If insulation is wet, the roof will lose performance and the deck can start to deteriorate even when the visible layer looks fine. A visit cannot prove the insulation is dry, but it can flag spongy areas, ponding that never clears and damp ceiling stains, which are the signs that justify a closer survey.
What a visit should leave you with
You should come away with three things. The first is a photographed record, with dated images of each outlet, gutter, row of laps and detail that was checked, plus anything that has changed since the last visit. The second is a note of the work done on the day, such as outlets cleared, fixings replaced, sealant renewed or moss removed. The third is a short list of what needs attention next, sorted into repair soon, watch and plan for.
Some premises need more than that. If your building has asbestos cement sheets on the roof, the duty to manage asbestos in non-domestic premises means the roof should be on your asbestos register, with its condition recorded and any disturbance kept to a minimum. We do not carry out work on those sheets as part of a routine visit, and we flag anything that looks damaged. If the roof is due for a decision about its future, our page on repair, overlay or replace shows how that choice is made.
Keep the records somewhere that survives staff changes. A roof file with each visit report, the original specification if you have it, and any guarantee paperwork makes insurance conversations, lease negotiations and sales easier, because the condition of the roof is something you can show rather than explain.
| Roof type | Checked at each visit | Typical small fix |
|---|---|---|
| Profiled metal sheeting | Laps, fixings, rooflights, valley gutters, edges | Reseal laps, replace washers and screws, treat early rust |
| Composite panels | Joints, flashings, ridge, panel edges, fixings | Renew sealant and cover strips, refix lifted trims |
| Single-ply membrane | Seams, upstands, corners, penetrations, outlets | Re-weld or patch seams, reseal terminations |
| Built-up felt | Blisters, splits, laps, granule wear, ponding | Patch splits, reseal laps, renew outlet collars |
| Parapets and box gutters | Copings, linings, outlets, overflows | Reseal joints, clear outlets, repair lining |
How often, and what it costs to do and not do
Twice a year suits most commercial roofs, with the autumn visit timed after the leaves have come down so gutters and outlets go into winter clear. Roofs under trees, roofs with a lot of plant on them and roofs on food or pharmaceutical premises may justify more. A newly laid roof should be looked at after its first winter. The question of interval gets its own treatment in our page on how often a commercial roof should be inspected.
On price, we do not publish a Beacon rate card, because the cost of a visit depends on the roof area, the access, whether a safe system of work needs edge protection or a platform, and what you want in the report. For orientation, one cost guide reports that a drone survey of a commercial roof typically runs from about £750 to £1,000, which is a different service from a hands-on maintenance visit, though a drone can be a sensible way to look at a roof that is unsafe to walk. Your fixed quote follows the survey.
The saving is easier to see when you set a visit against the alternative. The cost of a full commercial flat roof strip and replace comes out in one informal tradesperson answer at about £90 to £180 per m² and sometimes above, a low-confidence figure, but the scale is clear: a roof of a few hundred square metres is a large bill, and wet insulation under a leaking roof often turns a repair into a replacement. A roof that has been looked after tends to reach the end of its life on your timetable, not the weather's.
Starting a maintenance plan with Beacon
We start with a free survey of the roof, with photographs of your own premises, so that the plan is built on what is actually up there. From that we agree the interval, the scope of each visit and a fixed written quote. A sound roof gets a sound verdict from us. Should it show a fault that cannot wait, we say that too and set out the repair separately from the routine work.
Work is carried out with the access and edge protection the roof calls for, and we leave the site clear. Our written guarantee on workmanship runs for ten years and covers the repairs we make. Everything we do for business premises is gathered on the commercial roofing in Basingstoke hub. A visit can be booked on 01256 213956, or by WhatsApp.
