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Vector

For facilities managers

Vector is not an emergency roofer. Vector is your consultant for a permanent fix after the leak diverter.

Water is through the ceiling, the roof above is a green roof or a podium, and a roofer has already had a look. This page is what happens next if you want it fixed once.

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By Ben Hickman, Technical Director  ·  8 October 2026  ·  Updated 8 October 2026
Contributing author, CIRIA C817 (Blue Roofs) · contributing committee member, BS 8102:2022 revision

What we do and what we don't

The immediate response to water in an occupied building is yours: a leak diverter above the ceiling, buckets below, the electrics isolated, the occupants looked after. We do not do that, and a good leak diverter arrangement is usually the right call.

What we do is find out where the roof is actually failing, through the green roof build-up and without stripping it; agree a small, marked opening-up with your contractor; witness the repair; and verify it. If the build-up suits, we can put a moisture sensor in while the roof is open so that the next time water reaches the deck you get a notification instead of a ceiling. If the roof is leaking right now, phone 020 3137 6722; a form is not the right route for that.

The thing nobody wants to hear on day one

The fix is not immediate, and rushing it is the most expensive mistake available. People are understandably panicked and looking for something done now. When the investigation and the clear identification of cause get skipped, what follows is a half-hearted repair in the wrong place, niggles that continue, another repair that is not necessarily the right one, and months of it. Every round makes it harder to tell what actually happened, and every time it rains the occupants expect the worst. Once that goodwill goes, the repair gets harder and the costs climb.

The stain on the ceiling is almost never under the defect. Water travels sideways through a green roof build-up, often ten to fifty metres, sometimes a floor or two down, before it finds a way through. Lifting the planting above the wet patch finds nothing, disturbs sound waterproofing and makes the eventual investigation harder. Do not let anyone do it.

What to send us this week

  • A copy of the roof plan with every point of ingress marked: rooms, ceiling positions, columns, slab joints
  • When it happens: during rain, hours after, only in heavy rain; first time or a repeat; anything it coincided with
  • The as-built details and O&M, so we know what the build-up is
  • The maintenance record, including any previous repairs and who did them
  • Photographs of the ingress and of the roof surface

An initial site inspection is typically a few days away, and a great deal is done before then from the drawings and your record. We will tell you whether a through-build-up survey is viable for this roof before anything is quoted.

What the survey asks of you

The survey needs the roof to be leaking while it is measured. Before we attend, your team recreates the leak by watering the deck, with leak diverters in place below; we give guidance and suggest equipment, sometimes as simple as a timer on a tap. We only want to be on site once the leak is running. Where the people under the roof are not the people responsible for it, get written permission for access and for the watering sorted early; it is often the slowest part.

On the days themselves: two of the Vector team, usually two consecutive days, walking the roof and measuring in a grid. Planting does not normally need to be moved. If it does, we agree it in advance and your team or the landscaper does it.

What you get back

  • A report, typically two weeks after the site days, with a contour map of the roof showing the leak locations and any suspicious areas
  • A call to talk it through and agree where the contractor opens up: typically a minimum of about a square metre per location, enough to repair properly
  • Our attendance when the membrane is exposed, to confirm the defect and witness the repair, so the owner, the roofer, the membrane supplier and the occupants all get the same certainty
  • The option of a moisture sensor in the repaired area, so the roof reports on itself from then on

Roof above an occupied building leaking again?

Send the roof plan and the pattern of ingress. If it is leaking now, phone 020 3137 6722.

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