Roof Evidence & Repair Guide
What roofing photographs should show, what they can prove, what they cannot, and how to read the evidence behind any recommendation you are given.
The images that make a roofing recommendation checkable: the defect close up, its position on the roof, and the surrounding condition.
What roof photographs can and cannot establish about a leak, and why images usually support rather than prove a diagnosis.
What images can contribute to a renewal decision, and which evidence has to come from beneath the covering.
What should be documented before you accept a reroofing recommendation: failure pattern, fixings, underlay and why repair will not hold.
The specific evidence to request when told a roof cannot be repaired, and what a well-founded answer includes.
How existing roof imagery helps a second contractor assess the same evidence, and why it does not replace their own inspection.
How naming the defect and its cause in a quotation protects the homeowner and makes competing prices comparable.
How to compare conflicting roofing recommendations by examining the diagnosis and evidence behind each rather than the price.
The findings that indicate general deterioration rather than an isolated defect, and why the distribution of faults matters.
Why slates that keep slipping usually point to fixing failure, and the evidence that confirms or rules it out.
What nail fatigue is, why it releases sound slate, and what it means for whether a roof can be repaired or needs re-laying.
Why the most obvious defect is not always the cause of the problem, and how to test whether a diagnosis really fits the symptoms.
The short answer
It should show the failure itself — a split, a lifted edge, lead pulled from its chase or a cracked mortar fillet — and enough of the surrounding junction to see where on the roof it sits. A close crop with no context proves very little about the extent of the problem.
A visible split, gap or lifted edge in the flashing, with the junction around it.
Repair soon · Inspection needed to confirm
An image shows that a detail has failed, not how long water has been getting past it or what condition the timber and underlay behind the junction are in. That needs the flashing lifting.
Illustrative example — not a record of a completed job
Ask for one close image and one wider image of the same detail before agreeing to replace a whole flashing run.
The short answer
A slipped slate sits lower than its neighbours, often at a slight angle, sometimes overhanging the course beneath or caught on the gutter. From the ground it shows as a dark, irregular shadow breaking an otherwise even line. The slate itself is frequently undamaged — the fixing has let go.
One slate out of line and lower than the course around it.
Repair soon · Inspection needed to confirm
You can see that a slate has moved; you cannot see from the image why. Whether one nail happened to corrode or the whole roof is at the same stage is only settled by examining recovered nails and neighbouring fixings.
Illustrative example — not a record of a completed job
Photograph the whole slope, not just the slate. Whether others have moved is what determines the scale of the work.
The short answer
Look for splits along fold lines, thinning or cracking at stress points, lead pulled out of its mortar chase, edges lifted away from the covering, and repeated mastic patching. A white bloom on the surface is normal oxidation and is not, by itself, a sign of failure.
Cracks along a fold, or lead visibly lifted from the roof surface.
Investigate · Inspection needed to confirm
Surface condition is visible; the state of the timber, felt or mortar bed beneath the lead is not. Lead that looks sound can still be leaking at a lap or upstand hidden from view.
Ask whether the whole run needs replacing or only the failed section, and ask for the evidence behind that answer.
The short answer
It is a reasonable thing to ask for and most roofers are glad to provide it. On work you cannot see from the ground, completion photographs are the only practical way to know what was done. Before-and-after images of the same detail, from the same position, are the most useful pairing.
Completion photographs record what the finished work looks like. They cannot demonstrate how the detail was fixed beneath the surface, so they evidence the outcome rather than the whole method.
Ask for completion photographs when you accept the quotation, not after the scaffold has gone.
The short answer
Look for recognisable context: your chimney, your neighbour's roof, a satellite dish, the colour and coursing of your own coverings. Ask for a wide shot as well as close crops, and ask for the date the images were taken. Generic close-ups with no surroundings are impossible to place.
Tight close-ups with no surrounding roof or landmarks visible.
Investigate
Recognisable surroundings confirm where an image was taken, not when. Ask for the capture date, and treat images with no context as unverified rather than as proof of anything about your roof.
Ask for one wide image per elevation alongside the close-ups. It resolves the question immediately.
The short answer
They help considerably, because they anchor the comparison to the same physical defects. With images in hand you can ask each contractor which of the visible faults their price covers. Differences that looked like pricing often turn out to be differences in scope once the evidence is shared.
Shared images equalise what each contractor has seen from outside. They cannot reveal concealed defects one contractor may have found by lifting coverings, so ask what each did beyond photographing.
Send the same images to each contractor and ask each to state which defects their quotation addresses.
The short answer
Yes. 'Repair roof' could mean two slates or two square metres. A quotation should name the elevation, the detail and the approximate extent, so both sides know what was agreed. It protects the contractor from scope creep as much as it protects you from underdelivery.
A named area defines what was agreed, not what will be found. Roofs sometimes reveal further defects once opened up, so a quotation should also say how additional findings will be priced.
Ask for the area to be described so precisely that someone else could find it on the roof.
The short answer
Yes, and it is common on older roofs. Bituminous felt becomes brittle and tears, particularly where sunlight reaches it at the eaves or where it has been repeatedly wetted. The covering above can look perfectly sound while the secondary barrier beneath has effectively stopped working.
Underlay that tears or crumbles when a covering is lifted.
Investigate · Inspection needed to confirm
Underlay condition cannot be assessed from outside. It is only visible where coverings are lifted or from within the loft.
Ask for underlay condition to be recorded wherever a covering is lifted, even on a small repair.
Reviewed by Aaron, Owner, Elite Roofing Services Cumbria Ltd — last reviewed .
