The number of repairs matters less than where they were. Map them, and the roof usually tells you plainly which of two quite different things is happening.
“We keep having to get someone out” is one of the commonest things we hear, and the question behind it is always the same: is this normal maintenance, or is the roof telling me something?
Most advice answers by counting — more than a certain number of repairs and you should replace. That is not much use, because six repairs to one stubborn chimney flashing and three repairs in three unrelated places mean opposite things. What actually diagnoses a roof is the pattern.
This costs nothing and it is the single most useful thing you can do before commissioning a survey. Sketch the roof — a rectangle per slope is plenty — and mark on it every repair you can remember, with a rough date.
Then look at the distribution. Roofs fail in one of two ways, and the sketch usually makes it obvious which.
The marks group together. Everything is around the chimney, or along one valley, or on one small area of a slope.
A single unresolved defect, being repeatedly patched rather than diagnosed. The commonest culprits are a chimney flashing that was never properly formed, a valley that silts up and backs water under the covering, a lead sheet too long for its own thermal movement, or a junction with an extension roof.
On Birkenhead's older stock, with its multiple stacks and parapets, this is a genuinely common finding.
Not replace the roof. Have the actual cause identified and fixed properly — which may mean forming a new lead flashing rather than adding another bead of mastic to the old one. A cluster of repairs in one place is a diagnosis failure, not a roof failure, and replacing the whole roof to solve it would be an expensive way of avoiding the real question.
The marks are spread across the roof with no relationship to each other. Different slopes, different elevations, different years, nothing linking them.
A general failure of something that is present everywhere. There are only three candidates, and all three are underneath the covering:
Replace. There is no repair that addresses a scattered pattern, because the problem is not in the places that have failed — it is in the places that have not failed yet. Every remaining fixing on that roof is on the same clock, and refixing them one at a time as they let go is a treadmill in which you pay for access every time.
In practice many roofs show both: a cluster around one junction and a scatter elsewhere. That means two separate things are true — a specific defect that needs diagnosing, on a roof that is also reaching the end of its life generally.
Treat the scatter as the decision-maker. If general failure is established, fixing the cluster in isolation buys you a properly detailed chimney on a roof that still needs replacing.
| What you notice | Usually means |
|---|---|
| Repairs at widening intervals | Roof is stable; each repair solved something |
| Repairs at shortening intervals | Underlying failure is progressing |
| Leaks only in wind-driven rain from one direction | A junction on that elevation |
| Leaks in any prolonged rain | Covering or underlay, generally |
| Water in cold weather without rain | Often condensation, not a leak |
| Nothing for years, then several in one winter | A threshold was crossed — usually the underlay |
That last row is the one that catches people out, and it explains why roofs seem to fail suddenly. Slates may have been slipping for years with the underlay quietly catching the water. When the underlay finally goes, every one of those gaps becomes a leak at once. Nothing changed on the roof that winter — the second line of defence simply ran out.
Ten minutes with a torch on a bright day, and preferably during or just after heavy rain, will confirm the reading.
A scattered pattern outside plus perished underlay inside is about as clear as this gets.
Two separate systems. Planning: a like-for-like re-roof does not materially affect the external appearance of a building, so under section 55 of the Town and Country Planning Act 1990 it is not development at all and needs no permission. A visible change of covering can be a different matter, particularly inside a conservation area, where the test is applied more tightly.
Building regulations: where more than 50% of the roof's surface area is renewed, or the work forms part of a major renovation, regulation 23 of the Building Regulations 2010 requires the roof to be brought up to current thermal standards so far as that is technically, functionally and economically feasible — 0.16 W/(m²K) for a roof in an existing dwelling. A patch repair does not trigger it, and neither does a roof over unheated space such as a detached garage.
Tell us what has been done and where, and we will tell you what the pattern means.
New roof installations in Birkenhead →
All new roof guides →
New Roof Installations Chester →
Complete new roofs, re-roofing and roof replacement across Chester, the Wirral, Deeside and the surrounding areas.
Tell us about the property and the roof in Birkenhead, and we will come back to you — usually the same day.
Prefer to talk? Call 07464 259566 · WhatsApp 0044 7464 259566 · Email Evensbuddy@yahoo.com