Roof Evidence & Repair Guide
What a failing roof actually looks like from the ground, from the loft and from above — and what each sign can and cannot tell you.
The visible signs that justify looking closer at a roof, what each one can and cannot tell you, and how to judge whether a repair is isolated or wider work.
The earliest signs that a roof is deteriorating — in the gutters, in the loft and along the ridge — and what each one suggests before a leak appears.
What a single missing slate or tile actually exposes, when it matters, and why the neighbouring fixings matter more than the gap itself.
How high winds loosen fixings, lift coverings and disturb ridge and verge details without visibly removing anything from the roof.
The difference between the settled line of an old roof and genuine structural movement, and what evidence separates the two.
What visible daylight in a loft indicates, which gaps are normal ventilation and which mean the roof covering has been breached.
The roofing issues that genuinely warrant prompt action — active water entry, structural movement, unstable chimneys and storm openings — and why.
The short answer
Repeated slipping usually means the fixings rather than the slates are failing. Nails corrode at a similar rate across a roof because they are the same age and share the same exposure, so once a few release, more tend to follow. Battens weakened by damp behave the same way. The pattern matters more than any single slate.
Several slates slipped over a season, often scattered rather than clustered.
Investigate · Inspection needed to confirm
Scattered, repeating slips across one slope point to age-related fixing failure. Slips clustered around a chimney, valley or verge usually point to that detail instead.
Illustrative example — not a record of a completed job
Ask for the condition of the recovered nails and battens to be recorded, not just the slates. That evidence is what separates a patch repair from a wider discussion.
The short answer
Fragments in the gutter mean material is breaking away above. On slate it is often delamination or fractures around old nail holes; on concrete tiles it is surface erosion; gritty grey sediment is usually mortar breaking down at the ridge or verge. Any of them is a reason to check the source before the gutters block.
Flakes, corners of slate or sandy sediment collecting in gutters and downpipe bends.
Investigate · Inspection needed to confirm
Keep a sample. Whether it is slate, tile or mortar points straight at which part of the roof is deteriorating.
The short answer
Moss is very common on north-facing and shaded Cumbrian roofs and is not automatically damaging. It becomes a problem when it holds moisture against coverings through freeze-thaw cycles, blocks gutters as it sheds, or grows thick enough to interrupt drainage between laps. Aggressive removal can cause more harm than the moss itself.
Thick growth bridging the laps, or moss shedding into gutters.
Monitor
Moss cover hides the surface underneath, so a heavily covered roof cannot be condition-assessed accurately until it is cleared.
Avoid pressure washing — it drives water under laps and erodes coverings. Ask for careful removal and for the roof to be reassessed once the surface is visible.
Reviewed by Aaron, Owner, Elite Roofing Services Cumbria Ltd — last reviewed .
