When a flat roof springs a leak, the first question is always the same: can this be patched, or does the whole thing need doing? A repair costs a fraction of a replacement, so it's the right answer more often than roofers who only sell new roofs will admit. But there's a tipping point where patching stops being thrift and starts being money down the drain. Here's how to tell which side of it you're on.
When a repair is the right call
If most of the roof is sound and the problem is localised, a repair is usually the sensible, cost-effective choice. Good signs that a fix will do:
- The roof is relatively young and this is its first leak, not the latest in a series.
- The damage is in one spot, often a split at a seam, a lifted flashing, or a single blister, rather than spread across the surface.
- The deck underneath still feels firm underfoot, with no soft or spongy patches.
- The rest of the covering looks healthy, no widespread cracking, bubbling or crazing.
In these cases we'll happily repair it and tell you honestly that a replacement would be overkill. A good repair to a sound roof can buy you several more years. If you have an active leak right now, we can also fit a temporary covering quickly to stop further damage while you decide.
When you're better off replacing
A replacement becomes the smarter spend when the roof is telling you it's had enough. The signs:
- You've patched it more than once, or you're chasing the same leak every winter. Repeated repairs usually add up to more than one proper job.
- Water is pooling and sitting on the surface long after it rains. Ponding points to a failing fall or a sagging deck, which a patch won't fix.
- The problem is the material itself, not one spot, felt that's blistered and cracked all over is at the end of its life.
- The deck is soft or sagging, which means water has already got into the timber below the covering.
- The roof is simply old. A felt roof past 15 years or so is living on borrowed time, and each repair is a smaller and smaller stay of execution.
The middle option: an overlay
There's a third path that people often don't know about. If your existing roof structure and deck are still sound, but the covering is tired, a GRP overlay can sometimes be laid straight over the top. You get a brand-new, seamless fibreglass surface with the full lifespan and guarantee, without the cost and mess of stripping the old roof off first. It's not always possible, the deck has to be dry and solid, but where it is, it's the best of both worlds.
Not sure? Get an honest look
The only way to know for certain is to have someone actually inspect it, check the deck, look at the falls, and see whether the trouble is one spot or the whole surface. We give a straight assessment and recommend a repair, an overlay or a replacement based on what your roof genuinely needs, not what's most profitable to sell. If it only needs a repair, that's what we'll tell you. For a sense of what a new roof would cost if it comes to that, see our guide to flat roof costs.
Free, fixed-price quote, no pressure. Call 07976 730433 or request one here.
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