Large roofs
Commercial flat roof assessment: retain, repair, re-cover or replace
Before committing to stripping a large roof, find out what it actually needs. We survey it, test what is there and set out the route, including full replacement where that is what the evidence shows.
The survey gathers the evidence. The assessment tells you what to do with it.
Only need to know what state the roof is in? That is a roof survey and condition report.
Or call us on 07593 196505
- Specialist flat roofing contractor
- Torch-on felt and liquid-applied systems
- Greater London and South East England
The decision
Before you commit to a full strip-off
The situation is a common one: a large existing roof that has reached the point of leaking, and a proposal on the desk to take the whole covering back to the deck and start again. Sometimes that is exactly the right answer. What decides it, though, is hidden under the surface: whether the insulation is wet, whether the deck is still sound, whether the layers are still bonded to each other, and whether the falls carry water to the outlets.
If those hold up, the roof may need much less than the proposal sets out. If they do not, the proposal may be the honest answer, and then it can be signed with the evidence behind it rather than on trust. The point of the assessment is to know which roof you have before the decision is made, not after the covering is off.
Large programmes reach beyond the boroughs we cover for repairs: an assessment can go anywhere in Greater London or the wider South East, and further afield by arrangement.
Process
How the assessment works
- Inspection. A first look at the roof and a review of whatever documents you hold, from drawings and earlier reports to a contractor's proposal. It is free, and it tells you whether a survey is needed at all.
- Survey. The evidence: measurements, cores through the build-up, moisture readings, adhesion tests and photographs. Its fee is fixed with you before the visit and deducted from the cost of the work if you go ahead.
- Assessment. The decision drawn from that evidence: one of the four routes below, with the reasons for it set out in writing.
A free inspection is always available, and so is a quotation for the work. On a large roof whose route is genuinely unclear, the survey is what decides that route, but it is never the only way to a price. And a tender that comes with a specification is priced from its documents, with no survey asked for.
Outcomes
The four routes
| Route | What it means | When it fits | What rules it out |
|---|---|---|---|
| Retain | The covering stays, with no major works: maintenance and planned inspections keep it going. | The covering still sheds water, the build-up is dry and the faults are minor. | Leaks through the main field, wet insulation, or a covering that has worn out. |
| Repair | What has failed is put right, whether details, outlets, upstands or local areas, and the rest of the covering stays. | The failures are confined to particular places and the field around them is sound and dry. | Failure spread across the roof, or wet build-up over large areas. |
| Re-cover | A new waterproofing layer over the existing covering, in torch-on felt or the liquid-applied system (HYDRONYLON). | Only where the existing build-up is dry, sound and adhered, the falls work and the upstands are tall enough to take the extra layer. | Wet insulation, a deck that has failed, layers that have come apart, or falls that leave water standing. |
| Replace | A strip to the deck and a new build-up, priced and carried out by us like any other route. | The insulation is wet, the deck has failed, the falls are wrong, or the building needs a new build-up. | A build-up that tests dry, sound and bonded, where a lesser route meets the need. |
On the roof
What we check
- Samples of the build-up. Cores cut through the layers, so what is there is seen rather than guessed.
- Moisture in it. Readings across the field, confirmed in the cores, because wet insulation decides more than anything else.
- Adhesion. Whether the layers still hold to each other and to the deck, tested rather than assumed.
- The deck from below. Staining, sag and fixings seen from inside the building, where the underside can be reached.
- Falls and ponding. Whether the falls carry water to the outlets, and where it sits after a shower instead.
- Outlets and gutters. Their condition, their capacity and how they join the covering.
- Upstands, details and rooflights. Heights, terminations, and whether a new layer still leaves room at the thresholds.
- Earlier repairs. What was patched, with what, and whether it held.
- Access and safety. How the roof is reached, what will carry a person and what edge protection the work will need.
The report
What you receive
- A written report, with photographs.
- The findings set out area by area.
- The recommended route, and the reasons for it.
- The alternatives considered, and why they were set aside.
- What must be true for a re-cover to work, wherever re-covering is in play.
- Notes on working in an occupied building: access, noise, hot works and phasing.
The report belongs to you. It can go straight to your consultant or your main contractor, and it is written to be read by them as much as by you.
Roles
Working within your project team
- Owner
- Consultant
- Main contractor
- Pluvian, specialist roofing package
We work inside the team you already have and do not need to take the project over. Where a main contractor runs the site, we come in as their roofing subcontractor, as set out for waterproofing packages under a main contractor. Where the building has to keep working while the roof is done, the phasing is set out for roofs over buildings that stay open.
Surveyor
Who carries out the survey
Surveys are led by Kamil Hala, who founded Pluvian and whose trade has been flat roofs since 2018. More about him is on the about page, and the certificate the company holds is listed on the accreditations page.
Questions
Frequently asked questions
Can every roof be re-covered?
No. A new layer only works over a build-up that is dry, sound and still bonded. Laid over wet insulation, a failing deck or layers that have let go, it seals the problem in under a fresh surface and the roof fails again from below. Testing what is there is how we know which kind of roof it is.
Will you tell us if the roof needs replacing?
Yes, and we price that too. Replacement is one of the four routes, not the one we steer away from. If the insulation is wet, the deck has failed, the falls are wrong or the building needs a new build-up, the report says so plainly and the replacement is priced like any other route.
Do we need a specification first?
No. A roof and a question are enough to start. If a consultant later writes a specification, the report gives them the evidence to write it from; if a tender already comes with one, we work from those documents instead.
Is the assessment free?
The inspection is. The survey behind the assessment carries a fee, which we agree with you before anyone visits and deduct from the cost of the work if you go ahead, and the assessment is delivered with it.
Can you work under our main contractor?
Yes. The survey can be commissioned by you or by them, and the roofing can then run as a specialist package inside their programme, with the method statements, attendances and handover documents a main contractor expects from a subcontractor.
What is on the table for this roof?
The building, a rough roof area and whether a replacement proposal has already arrived are enough to start. Drawings and earlier reports can come with the enquiry.
We need a little more before we can send that: the organisation, your name, an email address and a phone number, the postcode of the roof (or tick Several sites), and what is happening with the roof.
Please check the postcode of the roof: it should have letters and numbers in it.
Please take the link out of your message - photos can be attached with this form.
Sorry, that did not send. What you wrote is still here, so press send again when you have a signal. If it will not go, ring 07593 196505 or email office@pluvian.uk.
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Looking at your roof or your documents and pricing the work is free. A written condition survey with testing carries a fee, agreed before the visit and taken off the price of the work if you go ahead.
No specification yet? That's fine. We can start by looking at the roof and working out the right route.