A warehouse with a leak does not stop trading while the roof is fixed. A shop, a surgery, a school or a production line keeps going too. The people inside carry on with their day, and the roof above them is opened, repaired and closed again. That works well when it is planned and badly when it is not.
The risks are plain. Something falls through an opening and lands on a person or a pallet. Dust and noise disrupt the work below. Rain gets in through any gap while a section of roof is open. A tradesperson wanders into an area they should not. Each of these can be prevented, but only if someone has thought about them before the scaffold arrives.
This guide explains how occupied-building roof work is organised. It covers the duties the Construction (Design and Management) Regulations 2015 place on the people involved, how a roof is repaired in phases, with each opening closed before the crew leaves, how the space below is protected, what to settle about asbestos before work starts and what the people inside should be told. It answers a question owners often ask: can the roof be repaired without stopping work inside?
Can the building stay open?
Usually yes, and most roof jobs are arranged to make that possible. The real question is which parts of the building stay in use and which have to be emptied for a spell.
What decides it
The kind of roof work comes first. Patching a covering from above leaves the interior largely undisturbed. Replacing sheets or roof lights opens the roof and puts the space below at some risk. Taking the whole roof back and re-covering it is the biggest disruption of all. The use of the building is the second factor: a storage hall holding sturdy stock tolerates more than a clean room, a kitchen or a ward. The layout is the third, since a building with a ceiling void or lining under the roof is easier to protect than an open shell.
Where the building cannot stay open
Some areas do have to be vacated for a time. The floor directly under an opening is one, and the space under a roof light being swapped is another. A room that cannot tolerate dust is a third. In those cases the work is slotted into a shutdown, a weekend or a quiet period, and the affected area is emptied or covered. Our answer on repairing a warehouse roof while the business stays open deals with the common case.
Asking the right questions
The survey identifies what can stay and what cannot. We then agree with you, in writing, which areas stay in use and what protection each receives. That agreement is the foundation of the plan.
CDM duties for the client and the contractor
The Construction (Design and Management) Regulations 2015 apply to roof work on a commercial building, and they spread duties across the client and the contractors. Knowing who owes what avoids arguments later.
The client
The owner or occupier who commissions the work is the client. A client must see that sensible arrangements exist for managing the project and must pass on what is known about the building: asbestos information, earlier surveys, drawings, hazards. A commercial client cannot hand its duties to the contractor as a homeowner can, because the domestic-client rule covers only work on a person's own home that is not part of a business.
One contractor or several
Two or more contractors on a project means the client makes two appointments under regulation 5(1): a principal designer, and a principal contractor. A project with a single contractor puts a different job on that firm: preparing the construction phase plan, under regulation 15(5). If we are the only firm on your roof, the plan is ours to write. If a scaffolder, a specialist and ourselves are all engaged, someone has to coordinate, and the client must make sure the appointments happen.
What the plan holds
The plan sets out the safe method in order: access, fragile surfaces, edge protection, protection for the people below, welfare, emergency arrangements and the asbestos position. It is written around your roof and shared before work begins, then revised if the survey or the site changes things.
Our answer on what CDM means for commercial roof work goes through the duties in more detail.
Phasing: opening only what can be closed
The most useful discipline on an occupied roof is also the simplest. Each opening is closed again before weather or the working day can undo it.
Working in bays
The roof is divided into sections, usually along natural lines such as the purlin spacing or the extent of a slope. One bay is stripped, repaired and made weathertight before the next is touched. Temporary covers protect any bay left overnight. This makes the job a little slower than clearing the whole roof in one go, and it keeps the building dry.
Sequencing around the building's use
The order of the bays can follow what is happening below. Work above loading doors is set for quiet periods. Work above sensitive equipment is timed for when the equipment is covered or moved. Noisy tasks are fitted to the hours that affect people least. We agree the sequence with you or the building manager before starting.
Weather planning
Rain on an open roof is a real threat to the building underneath. We watch the forecast, keep tarpaulins and temporary covers ready and stop to close up in good time if conditions turn. Dates stay provisional because the weather owns the programme, and each day you are told what is open, what is closed and what comes next.
Handover at close of play
When the crew leaves, the roof is weathertight, edge protection is secured and the areas below have been checked. If anything is unfinished, we explain exactly what and how it is protected.
Protecting the space below
Even a careful job generates debris, and an occupied building needs protection beneath the work.
Catch protection and exclusion zones
Nets, boards or a protective deck below the opening catch what falls. Where the underside of the roof is exposed, an exclusion zone keeps people and stock out of the area directly underneath, marked and barriered. Routes through and around the area are agreed so staff know where to walk and where not to.
Dust, noise and fumes
Cutting sheets and removing old coverings creates dust. Hot works release fumes and need a hot-work plan, and in many occupied buildings cold-applied systems are preferred for exactly that reason. Machinery and tools are chosen with noise in mind. In sensitive areas, we cover stock, machinery and fittings, and sometimes seal the underside of the roof with temporary lining.
Fire precautions
Hot-work, welding and torch-on felt call for fire precautions: extinguishers on hand, a fire watch after work stops and a check of the areas below. Smoke detectors in the space below may need to be covered or isolated, and putting them back in service is part of the handover. Raise that with the building manager before work begins.
Special areas
Food areas, clean areas, server rooms and anywhere with pharmaceuticals or sensitive stock need specific measures. We ask at the outset whether any such area lies beneath the roof, and we plan accordingly. Our guide to fragile roof safety describes how the roof side is protected at the same time.
Asbestos before the first sheet comes off
For an occupied building, the asbestos question weighs more than usual, because disturbed fibres reach everyone inside as well as the roofing crew.
The starting assumption
HSE's advice treats a building from before 2000, whether built or refurbished then, as containing asbestos until information shows otherwise. On an older commercial roof the sheets themselves may be asbestos cement, and the soffits, linings and cladding beneath may include insulating board that looks like any other panel.
What the register gives you
The first thing we request is the building's asbestos register. It says what is present, where and in what condition. Where no register exists for an older building, a survey for asbestos is arranged before the roof is touched. MyJobQuote gives around £325 as a typical UK figure for an asbestos survey (September 2026), and a large site costs more.
If asbestos is found
The plan changes. Careful removal of whole asbestos cement sheets is non-licensed work under HSE's rules, while substantial breaking up makes it notifiable non-licensed work. Insulating board work that is more than short in duration can be licensable. Whatever the category, the area below is protected or vacated, any waste goes out double-wrapped under a consignment note, and occupants are told what is happening. An open skip is never used for it.
Our answer on whether you need an asbestos survey before roof work is a good companion read.
Cost, programme and how to start
Working around an occupied building changes both the method and the price, and it helps to hear that early.
What moves the price
Phasing takes longer than clearing a roof in one pass, and protection below has a cost of its own. Out-of-hours work, cold-applied systems in place of hot-applied ones, hoisting, scaffolding and exclusion zones all change the total, as do the roof's area and condition and how we reach it. No single figure applies across buildings. After the survey, our quote comes in writing as a single sum for the agreed work.
Programme
You get a sequence and, where useful, a likely pattern of working. Weather and survey findings can move dates, so what matters is a plan showing the order of work, the areas affected and how you will hear about changes.
Telling the people inside
Staff and tenants should hear what is happening, where, and what they need to do, such as moving vehicles, clearing a bay or avoiding a route. Name one contact for questions. Where several tenants share the building, the landlord or managing agent usually passes on the message and we supply the facts. During the job, a short daily word with the building manager covers what is open and what is shut. Notices at doors and on the floor mark the exclusion zones, and anyone moving into a new area is told before the crew arrives.
Information that helps us
The asbestos register and any earlier survey. Plans that mark roof lights, plant and drainage. Details of sensitive areas below the roof. Opening hours, shutdown dates and limits on noise or access. The names of the people who must be told. With those, the plan is built around the real building. Our commercial roofing page lists the systems we use and the sectors we cover.
