What A Roofer Looks At That You Would Not

Key takeaways

• The inspection usually starts inside, in the loft, not outside on the roof.
• Previous repairs are the most informative thing on any roof, because they mark where it has always failed.
• Sound, feel and colour carry information that photographs do not.
• A proper assessment produces findings, not just a price.
• You can judge the quality of an inspection by what you are told rather than by how long it took.

It starts in the loft, not on the roof

The instinct of a homeowner reporting a leak is to point at the ceiling and expect somebody to climb up outside. The instinct of an experienced roofer is to ask for the loft hatch. From underneath, in daylight with the electric light off, the roof tells you where water has been travelling: dark run marks down rafters, staining that starts high and trails downwards, wet or compressed insulation, and daylight where there should be none. Those marks lead uphill to an entry point. Only once that entry point has been narrowed down does going outside become useful, because at that stage they are checking a specific suspicion rather than looking for something wrong.

The underlay, which decides everything else

The first structural question is what sits beneath the covering. No underlay at all means an older roof where the tiles are the only barrier and any gap is an open hole. Bitumen felt means a mid twentieth century roof where the underlay has a shorter life than the covering and may already have failed. A breathable membrane means recent work and a roof with a functioning secondary barrier. That single observation changes the urgency of everything else, and it is why an assessment carried out entirely from outside is missing the fact that most influences the recommendation.

Battens, fixings and the sound of a slate

In the loft, the battens are visible between the rafters and their condition can be tested by pressing: sound timber resists, softened timber does not. Nail points show as rusted tips coming through, and heavy corrosion across many of them says the fixings are near the end of their life whatever the covering looks like. Outside, a slate lifted and tapped rings clearly when it is sound and thuds dully when it has begun to delaminate. That sound is how the reusable proportion is judged on a strip and relay, and it is not something that can be assessed from a photograph or from the ground.

Reading the mortar

Mortar carries a surprising amount of information. Colour and texture indicate age and mix, and a patch that differs from its surroundings marks a previous repair. A hard grey cement pointing on an old soft building tells you somebody has repaired it with the wrong material, which predicts where the next cracking will appear. Recessed joints mean erosion has been going on for years. Fresh looking mortar high on a chimney on an otherwise weathered stack means work was done recently, which prompts the question of why. None of this requires equipment, and all of it comes from having seen a great many roofs.

Previous repairs, which are the best evidence available

The most informative features on most roofs are the attempts already made to fix them. A patch of mastic around a flashing marks a junction that has leaked before. A cement fillet where lead should be marks a shortcut somebody took, probably decades ago. Mismatched tiles mark where units have been replaced, and their distribution shows whether failures were isolated or spread. A previously repaired valley suggests a valley that concentrates more water than it was built for. Roofers look for these first because a roof that has been repaired three times in the same place is telling you exactly where it will fail again.

The junctions rather than the field

An experienced eye spends very little time on the open middle of a slope and a lot on the edges and junctions, because that is where roofs actually fail. Ridge and hip bedding, the verge at each gable, every abutment against a wall, both sides and the back of any chimney, valleys, the eaves detail and how the underlay dresses into the gutter, and around every roof window or dormer. A quick assessment that covers the junctions is more useful than a long one that covers the slopes, and it is a reasonable question to ask afterwards: which junctions were looked at, and what state were they in.

The line of things

Roofs are regular, so irregularity carries meaning. A course line that waves rather than running straight suggests the batten behind it has dropped or the fixings have let go. A ridge that dips indicates structural movement rather than a covering problem. A tile sitting slightly proud of its neighbours has been lifted and dropped back, probably by wind, and has lost its seating. A gutter that is not parallel to the eaves has lost a bracket or the fascia behind it has softened. None of these are damage in the obvious sense and all of them predict where damage is coming.

What is not on the roof

A good inspection also looks at the things around it. Where the downpipe discharges, and whether that gully runs. Whether the ground has been built up against the wall. Which way the property faces and how exposed it is, since that changes what specification is appropriate. What trees overhang and what they drop. What the neighbouring properties look like, since houses built together age together. Whether an extension or conversion has introduced junctions the original roof did not have. All of that context shapes both the diagnosis and the recommendation, and none of it is visible if somebody only looks at the tiles.

Photographs, and why you should expect them

You are commissioning an assessment of surfaces you cannot see, which makes photographs the actual deliverable rather than a courtesy. Expect images of each junction, of anything identified as a defect, and of the general condition of the covering, and expect them to be explained rather than simply sent. Photographs also give you something to compare against next time and to show to a second contractor without them having to set up access again. A roofer who takes them as a matter of course is telling you something about how they work, and one who cannot produce any is asking you to take a recommendation entirely on trust.

The difference between findings and a price

This is the clearest test of whether an inspection happened. A price on its own is a proposal. A price accompanied by findings, meaning the state of the underlay, the condition of the fixings, which junctions were examined and what was wrong with them, is an assessment. Where two contractors describe the same roof and differ only on cost, you have a genuine choice in front of you. Where their descriptions do not match, you do not have two prices for one job, you have evidence that only one of them examined the building. Asking every contractor what they found, before asking what they propose, is the most useful question available to a homeowner.

How long it should take

There is no correct duration, and both extremes are informative. A visit lasting a few minutes with no loft access and no photographs has produced an impression rather than an assessment. Conversely, a long visit is not proof of thoroughness. What matters is coverage: inside and outside, junctions specifically, the underlay established, and an account of what was found. On a simple estate roof that might be thirty minutes. On a large house with several levels, valleys and a parapet gutter, it is a considerably longer job, and a quote produced for that building in a quarter of an hour is not based on having seen much of it.

What a roofer will not be able to tell you

An honest assessment has limits worth knowing about. Nobody can tell you exactly how many years a roof has left, because that depends on weather nobody can forecast and on failures that are progressive rather than scheduled. Nobody can be certain a leak is fixed until it has been through the weather that caused it, which is why a reputable contractor will say they are confident rather than certain. And nobody can see inside a wall or under a covering without opening it, so some questions genuinely require investigative work rather than an opinion. A roofer who deals in certainties about all of those is offering reassurance rather than assessment.

Frequently Asked Questions

Should a roofer look in my loft?

For anything involving a leak, yes, and usually first. The underside shows where water has travelled through run marks on the timbers and damp insulation, which lead uphill to the entry point. It also establishes what underlay exists, which changes the urgency of everything found outside.

What is the most informative thing on a roof?

Previous repairs. Mastic around a flashing, a cement fillet where lead should be, or mismatched tiles all mark places the roof has failed before. A roof repaired three times in the same spot is indicating precisely where it will fail again, which is more useful than any amount of general condition assessment.

Why do roofers tap slates?

Because sound carries information the eye does not. A sound slate rings clearly when tapped; one that has absorbed water and started to separate into layers thuds dully. It is how the reusable proportion is decided when a roof is stripped and relaid, and it cannot be assessed from a photograph.

How can I tell whether an inspection was thorough?

By what you are told rather than how long it took. Ask what the underlay is, which junctions were examined and what state they were in, and what the fixings look like. An answer to those means somebody looked. A price with no findings means somebody formed an impression.

Should I expect photographs?

Yes. You are paying for an assessment of surfaces you cannot see, so images are the deliverable rather than a courtesy. They also let you compare condition over time and show a second contractor what was found without them needing to arrange access again.

How long should a roof inspection take?

It depends entirely on the building. A simple estate roof might be half an hour. A large house with multiple levels, valleys and a concealed gutter is considerably longer. What matters is coverage rather than duration: inside and out, junctions specifically, underlay established, and findings reported.