Most advice on this subject assumes the slate is fine and the nails are the problem. In Maesteg that is usually true — but not always, and the exception is worth understanding, because it points at a completely different answer.
Welsh slate is extraordinarily durable, and on most roofs it outlives the nails holding it. A slate is fixed with two of them near its head; they corrode over decades and eventually let go, and the slate slides out intact with clean holes.
That is the common finding on the terraces here, and it makes the decision a question about the fixings: are they failing across the whole slope, or only where these came from? Local means repair. General means the roof is asking to be recovered, and a series of patches will simply follow the failure around.
Slate is a laminated stone. It formed in layers and it splits along them, which is what makes it usable as a roof covering in the first place. Under sustained wetting and freezing over a long enough period, those same layers can begin to separate on their own.
That is delamination, and it is a genuinely different failure from nail corrosion. The fixings may be perfectly sound. The slate is coming apart.
Why this matters for the decision. Nail failure can be repaired, and on a good roof it should be. Delamination cannot — you cannot re-fix a slate that is coming apart, and slates around it are the same age, from the same quarry, and have had the same weather. Widespread delamination is one of the few findings that genuinely points at recovering rather than repairing.
It is also the reason to keep what came down. A broken slate you can hand to a roofer answers this question in about four seconds, and a photograph rarely does.
A proper assessment is not a glance at the gap. It covers:
That last one is the reason a wet roof is hard to assess properly, and one of several reasons a decision this expensive should not be made in the middle of a storm.
Replace what is missing, re-secure the surrounding area, make good. Quick, much cheaper, and entirely right where the rest of the roof has life in it. Anybody telling you a roof needs replacing when this would do is not being straight with you.
Strip the slate, replace battens and underlay, relay the covering — reusing as much sound original slate as possible, since on most roofs that is a good proportion of it. On a roof with widespread delamination it will be less, and the quotation should say what proportion is expected to be reusable rather than leaving it open.
A recover is also the point at which a valley-terrace roof can gain the things it never had: underlay where there was none, and mechanically fixed ridge and verge instead of mortar that will crack again.
The covering gets all the attention, but on a wet valley roof the condition of what is under it frequently decides the answer.
Thin timber strips the slates are nailed to. They are the part that suffers most from sustained damp, because they sit directly beneath the covering with water running past them. Soft, split or crumbling battens mean slates cannot be securely re-fixed however sound the slate is — there is nothing to nail into.
Many older terraces here were built without it. Where it exists and has perished — brittle, torn, sagging between rafters — the roof has lost its second line of defence, and that cannot be put right without stripping the covering.
The structure itself. Repeated wetting and drying over years is what leads to rot, and rot moves the job from roofing into carpentry and structural work.
This is why a proper assessment includes the loft, and why a roof that has been leaking quietly for a long time sometimes cannot be repaired at all in the ordinary sense. The covering was never the problem.
Access is a large part of the cost of any roof repair, and you pay it in full every time somebody comes out. On a valley-side terrace with awkward rear access it can be most of a small job.
So three repairs over three winters is three lots of access, three call-outs and three sets of disruption, on a roof that is no better than it was. Ask for both options priced, with a view on how long the repair is expected to hold, and compare real numbers rather than instinct.
T & T Roofing South Wales will tell you which situation we think you are in and why, across Maesteg and the Llynfi Valley. If a repair is the right answer, that is what we will quote for.
Either something struck the roof, or the slate is delaminating — coming apart along the layers it formed in. If nothing hit the roof, the second is likely, and it points at recovering rather than repairing.
Slate is layered stone. Sustained wetting and freezing over a long period can make those layers separate. The fixings may be perfectly sound; the slate itself is failing, and it cannot be repaired.
Keep what came down and look at it. Whole slates with clean holes mean the nails failed. Slates splitting into sheets, with soft or crumbling edges, mean the slate is going. A broken slate in hand answers it immediately.
Usually a good proportion, because on most roofs the slate is the part still fit for service. Where delamination is widespread it will be less, and the quotation should say what proportion is expected to be reusable.
Storm damage in Maesteg? T & T Roofing South Wales will assess the roof, explain what needs repairing and give you a free, no-obligation quotation. Storm Damage Roof Repairs Maesteg has the full detail, or call us on 07766 547309.
Tell us what the weather has done and what you can see from the ground. We will come back to you — usually the same day.
If water is coming in now, please call rather than email — 07766 547309.
