Finding a Roof Leak: Evidence, Diagnosis and Lasting Repairs

What to Do if Water Is Coming In

Water near electrics, a bulging ceiling, falling material or suspected movement requires appropriate urgent assistance. Keep people away from the affected area and do not disturb ceilings or wet electrical fittings to investigate.

Do not climb onto the roof or enter an unsafe void to find the source. HSE explains that roof work requires planned access and precautions even for short inspection tasks, and surfaces should not be assumed safe to stand on. ^{[1] [2]}

For an active problem, use our emergency roof-leak action plan. If there is an immediate safety concern, deal with that before trying to find the cause.

What to Tell Us About the Leak

Let us know when the water appears, what the weather is like at the time and where you first notice it. Tell us about any recent roof repairs, new windows, plumbing work or changes to heating and ventilation, too.

If you can take photographs safely, a few pictures of the same area on different dates can help us see whether it is getting wet again or whether an old stain is still visible. There is no need to remove finishes or disturb materials to investigate.

On small screens, scroll the table sideways to view every column.

You do not need to diagnose the problem before contacting us. These details simply help us plan the inspection.

Why the Stain May Be Away from the Leak

Water can enter higher up the roof and travel along a timber, membrane or junction before reaching your ceiling. That means the defect may be some distance from the mark you can see indoors.

When we inspect a leak, we look at the roof outside as well as the signs inside your home. We will explain why we think a particular area is responsible and how the proposed repair should help.

Older buildings can be particularly difficult to assess. Historic England's 2026 damp guidance recommends looking at the wider picture rather than relying on a single reading. If the cause is still uncertain, we will explain what we have found and what needs further investigation. ^[3]

Where We Look on a Pitched Roof

We check for damaged or slipped tiles and slates, but also look closely around chimneys, valleys, adjoining walls, ridges and roof windows. A fault at one of these junctions can cause a leak even when most of the roof covering is sound.

On a slate roof, for example, a failed fixing may allow an otherwise usable slate to slip. We need to establish whether the leak comes from that area or a nearby junction before recommending the repair. ^[4]

We will explain the relevant findings and what they mean for your roof. If we recommend wider work, we should be able to show why a local repair would not be enough.

What We Check on a Flat Roof

On a flat roof, we look at the waterproof covering, edges, raised junctions, openings and outlets. We also consider the structure beneath it and how water drains, because a surface defect and poor drainage can occur together.

The NFRC's summary of BS 6229:2025 highlights roof falls, level surveys and handover records. In practical terms, we need to understand why water is collecting before deciding whether a surface repair will solve the problem. ^[5]

Any repair needs to suit your existing roof. EPDM rubber, GRP fibreglass and felt have different product requirements, so the same repair compound will not provide a lasting solution on every covering. ^{[6] [7] [8]}

Leaks Around Chimneys and Roof Windows

If you have a stain near the chimney, we check more than the lead flashing. The surrounding roof, mortar, brickwork and moisture from the flue can all be relevant. We need to identify the cause before recommending repointing or new leadwork. ^[3]

Around a roof window, we check the window itself and how it joins the roof. Flashing, underlay, insulation and the internal seals all do different jobs. VELUX's installation guidance shows why these connections need to work together. ^[9]

Read the dedicated chimney leak guide or roof-window guide for more detail about the problems we look for in these areas.

Do Not Confuse Condensation with Rain Entry

Moisture that appears during cold weather without rain may have a different cause from a leak that starts in a downpour. Room moisture, heating patterns, insulation and ventilation can all be relevant.

Energy Saving Trust explains why moisture and ventilation need attention before more roof insulation is added. Extra insulation alone may leave a damp problem unresolved, even if the room feels warmer. ^[10]

You can have condensation and a rainwater leak at the same time. If we find one problem, we still consider whether it explains everything you have noticed and tell you if further checks are needed.

What a Roof Inspection Can Tell You

Some defects are visible during an inspection; others are hidden beneath the covering. Photographs can help, but closer access or carefully opening an area may be necessary. We will discuss any additional investigation with you before it goes ahead.

If testing is suggested, ask what it can establish and how the area will be protected and made good. Please do not try a hose test, puncture the covering or disturb a junction yourself. Testing needs a suitable method and someone competent to carry it out safely.

If you need a written report, agree this before the visit. It should explain what was checked, what we found, any areas we could not see and the next steps. Our roof inspection guide explains what to discuss when arranging a visit. ^[1]

Why Repeated Patches Sometimes Fail

A patch can fail because it has missed the source, used an unsuitable material or repaired only one of several defects. Sometimes the surrounding roof has deteriorated too far for a small repair to last.

Tell us what has already been tried, whether it helped and when the leak returned. Previous invoices and photographs are useful. They help us decide whether the original diagnosis needs another look.

Widespread deterioration can make replacement the sensible option, but several unsuccessful patches do not automatically mean you need a whole new roof. Our repair-or-replacement guide explains how we weigh up the options with you.

Agree the Repair and the Follow-Up

Your quote should set out the area to be repaired, materials, access arrangements, work included and any limitations. We will discuss how any hidden damage would be recorded, priced and agreed with you. Citizens Advice also recommends getting quotations and agreements in writing. ^[11]

Keep the invoice and any photographs after the repair. Ask when to review the area and whether it needs time to dry before you redecorate. An old stain can remain after a leak is fixed, so tell us if you see fresh moisture or the mark starts growing again.

For roof leak detection and repairs in Newcastle, Gateshead or Sunderland, send us your postcode, a few details about the leak and any photographs you can take safely. We can then discuss the next step with you.