Butynol was the default flat roof membrane in New Zealand for decades, so a great many Auckland homes still have it up there. When it starts leaking, the question we get asked most is whether it can be patched or whether the whole thing has to go.
Here is how we answer it.
Age is the first test
Butynol stays flexible for around fifteen years. Inside that window the sheet can still move with the building, and a repair bonds properly and holds.
Past fifteen years the material hardens. A patch bonded to a brittle sheet puts a stiff spot in the middle of something that still needs to expand and contract, and the failure simply migrates to the edge of the patch. That is why people find themselves patching the same roof every second winter.
Where it is failing matters more than how much
A single puncture from a dropped tool on an otherwise sound roof is a repair, regardless of age. Seams opening up in several places are not, because seam failure is a symptom of the adhesive giving up everywhere at once. You are only seeing the two spots that have got bad enough to let water through.
The same goes for upstands. If the membrane is pulling away from a wall in one corner, that can be redressed. If it has shrunk back at every upstand on the roof, the sheet itself has contracted and there is nothing to redress it with.
Count what the patches have already cost
The maths that catches people out is the cost of waiting. Several patches over a few years, plus the internal repairs when one of them lets go before you notice, add up to a meaningful share of a replacement. It also means years of moisture getting into the substrate, and rotten substrate is what turns a straightforward reroof into a much bigger job.
What we do about it
We come and look, lift a section, check the substrate underneath and photograph what we find. If the roof is a genuine repair candidate we will say so and quote the repair, which is a smaller job for us than a replacement.
If it is not, we will show you the photos and explain why. We would rather do one proper job than three patches, and you would rather pay for one.
Send us photos of the problem area and we will give you an honest read before anyone comes out.