A roof on a block of flats belongs to nobody in particular and costs everybody something. The freeholder or the right-to-manage company is responsible for it, the managing agent organises it, and the leaseholders usually pay for it through the service charge. When the work is large, the leaseholders have to be consulted before a contract is signed, and that process is known as section 20. The consultation is about money and fairness, but it runs on technical paper: a survey, a specification, and prices from contractors who have all priced the same thing. A weak specification produces weak consultation, wrangling over what was meant and variations on site. This guide is written for managing agents and leaseholders in and around Bath, and it follows a big roof job in the order it happens. Treat it as background reading, since only your lease and a solicitor can say what binds you. Our part is the roof, which sits under our commercial roofing work.
What section 20 is, and why a roof triggers it
Section 20 is shorthand for the statutory consultation a landlord must carry out before major works whose cost is passed on to leaseholders. If the steps are skipped or done badly, the amount the landlord can recover may be restricted, which is why managing agents treat the process with care. The rules sit in section 20 of the Landlord and Tenant Act 1985 and the Service Charges (Consultation Requirements) (England) Regulations 2003. For works, consultation is needed when any one leaseholder's contribution would be more than £250, and if it is skipped the landlord can usually recover no more than £250 from each leaseholder unless the First-tier Tribunal grants dispensation. The notice stages and their timings are detailed, so check them with your solicitor or the managing agent's legal adviser rather than relying on a roofer's summary.
Roofs trigger it because they are among the largest single items of building expenditure. A full renewal of a pitched or flat roof over several flats is far beyond the scale of routine repair, and a scaffold wrapped around a four-storey block adds a considerable sum before any roofing material arrives. A repair that began as a few slates can grow into major works once the survey shows the battens or the lead beneath are in poor condition.
The roofer's role in this is practical. We do not run the consultation. We supply a clear description of the defects, a defined scope and a price that can sit next to rival ones, which gives the people running the consultation something firm to work from. An agent who arrives with a surveyor's report, a photographic record of each defect and a written specification is far better placed to answer leaseholders than one who has a one-line quote.
Establishing what the roof needs
Consultation begins with a question that sounds simple: what is wrong, and what must be done? On a block of flats the answer is often disputed, because some leaseholders see a ceiling stain and want a patch, while others see a covering that has run its course and want it renewed.
A survey settles this with evidence. For the roof itself, we walk every slope and flat area, record the covering and its condition, and photograph the defects in place. We check the lead in valleys, parapet gutters and abutments, look at the chimneys that serve flats below, test the outlets and rainwater goods, and inspect the loft or roof void from inside where it can be reached. The reason for working from inside as well as outside is that water entering at one point travels, and a stain in a top-floor flat may start metres away.
The report should separate three categories. Urgent work stops water entering now. Necessary work will be needed within a short horizon and is cheaper done while access is in place. Desirable work improves the building but could wait. This gives leaseholders a fair picture of what is being proposed, what is being deferred, and why. It also guards against the situation where a patch repair is carried out, the leak returns, and the second visit costs more than the roof would have cost to renew the first time.
If the leaks are emergencies, we make the roof safe first. Making safe is not the same as a permanent repair, and it should be recorded as such so that the consultation is not skipped on the pretext of urgency.
Writing a specification leaseholders can follow
The specification is the document that every contractor prices, and it is the document leaseholders may be asked to comment on. A good one reads like a clear description of the job, with enough technical detail that two roofers cannot interpret it differently.
It should state the covering to be used and why, the treatment of the timbers and deck beneath, the underlay and battens, the lead and its code (the thickness grading of sheet lead), the ridge and verge details, the rainwater goods, and how each junction with a neighbouring roof or wall is to be formed. It should also say what is not included, and how unforeseen defects will be handled. On an older block, rotten rafter ends or wet insulation discovered during the strip are the usual surprises. A provisional sum with a clear rate for extra timber avoids an argument on site.
The covering is where matching matters. A Victorian mansion block in Bath with a natural slate roof should come back as natural slate, not a cheaper substitute, where the block is listed or in the conservation area, and the specification should state it. On a flat roof the choice of system, whether built-up felt, single-ply or another, belongs here too, and our guide to built-up felt roofing describes one of the common options and its weak points.
The specification also records the access arrangements, the working hours that suit residents, how bin stores, car parking and entrances will be protected, and how waste leaves the site. Residents are the audience for much of this. A leaseholder who knows where the scaffold will stand and when the noisy days fall will complain less, and that is helpful to everyone.
Tenders, comparison and the preferred contractor
Consultation normally involves obtaining estimates, and the managing agent will want to compare them. The comparison only works if each contractor has priced the same scope. Give every firm the same specification, the same drawings or photographs, and the same access to the roof. Ask for prices broken into the main parts of the job, such as scaffold, strip and disposal, timber repairs, covering, lead and rainwater goods, so that a difference in total can be traced to a specific line.
Do not choose on the lowest figure alone. A price that is far below the rest usually reflects something left out: new battens, lead renewal, a realistic scaffold, or an allowance for repairs when the deck is opened up. Ask what happens if the timbers below are worse than expected, and what rate applies. Ask how long the work is expected to take and what sequence is proposed. For the guarantee, ask what it covers and who gives it. Ours is a 10-year written guarantee on workmanship, and we explain exactly what it covers in the quote.
Where the contract does not go to the lowest estimate or to a contractor the leaseholders nominated, the landlord must give reasons within 21 days of signing it, so make those reasons easy to give. A short comparison note, naming the scope each firm priced and the reasons for the recommendation, is more persuasive than a spreadsheet of totals. Leaseholders are invited to nominate a contractor at the first stage, and the landlord must try to get an estimate from a nominee, which is another reason for a specification that anyone can price.
We give a fixed price in writing after the survey, set out by item. That lets an agent put our figure beside others without guessing what is inside it.
Listing, conservation and approvals
Many blocks of flats in Bath occupy buildings that were built as something else: terraced houses converted, villas split up, or a grand crescent house divided. That affects the roof work in two ways.
First, approvals. Work that alters a listed building needs listed building consent, and the consenting body is B&NES Council. B&NES guidance on listed buildings is blunt. Contact the council first, remember that planning permission and listed building consent are separate, and note that proceeding without consent is a criminal matter. The city is a World Heritage Site, with roughly half of it inside the conservation area, so an unlisted block can still carry constraints. Renewal in the same material is the simpler case. Swapping the covering, adding a rooflight or altering a parapet is worth raising early. Our companion guide on commercial roofs on listed buildings covers the consent side.
Second, Building Regulations. Small re-roofing jobs, under 25 per cent of the envelope and under 50 per cent of the roof, normally sit outside approval. Renewing a whole block roof goes past the roof figure, so approval is required, and the roof's insulation might need improving to meet today's requirements. Separately, a covering 15 per cent heavier or more brings its own approval and a structural look at the rafters. Either B&NES building control or a registered building control approver signs it off, and we take care of the paperwork for notifiable jobs.
Build these steps into the programme. Consultation, consent and approval each take time, and a project that has to wait for listed building consent after the leaseholders have approved the contract is a project in trouble.
Running the job on site
Once the contract is placed, the aim is a roof delivered in the sequence promised, with residents kept informed. The scaffold goes up first, with a protected route past entrances and a covered walkway where people pass below. The roof is stripped in sections, not all at once, and each section is dried in at the end of the working day so that a night of rain does not reach a top-floor flat. That is more demanding than clearing the whole roof, but it is the correct approach on a building where people live beneath.
Every uncovered area is a risk, so the forecast shapes the programme. We watch the forecast, keep tarpaulins and temporary covers on site, and phase the work so that the exposed area never exceeds what we can close in the time available. Where a parapet or box gutter is opened up, its replacement lining goes in before the weather turns, not after it.
Hidden defects need a decision process. When rotten timber or wet insulation is found, the agent should be told the same day, with photographs, and a written instruction should follow before extra work proceeds. This protects leaseholders from surprise charges and protects the contractor from dispute. A site visit by the surveyor or agent at a mid-point, and again before the scaffold comes down, catches most problems while they are cheap to fix.
Finally, access to the roof afterwards. If a solar array, aerial or plant is to be added later, the roof should be built to take it, and our note on solar panels on commercial roofs explains why the order of work matters. At handover the agent receives the guarantee and pictures of the finished details, and the scaffold and rubbish are gone.
After the work: records and the next cycle
A major roof renewal should leave a paper trail. The managing agent needs the final specification as built, the photographs of hidden work before it was covered, the guarantee, and any building control completion certificate. Those documents answer questions years later, when a leaseholder sells and a buyer's solicitor asks about the roof, or when a leak appears and the question is who is responsible.
It should also leave a maintenance plan. Even a new roof needs its outlets, valleys and gutters cleared, and inspected after storms. In a block with no resident caretaker, nobody does this unless it is arranged, and the cost of an annual visit is small beside the cost of the first blocked gutter. We can set out a sensible inspection routine as part of the handover, so that the agent has a defined list of tasks and a date for the next check.
The last point is communication. Leaseholders who were consulted, informed during the work and handed a clear summary at the end are more willing to support the next round of planned works. The roof is a long-term asset, and the best sign of a well-run project is that nobody has to think about it for a long time afterwards.