Storm season · 6 min read
Hail damage in Windhoek: what it does to sheeting and to tiles
Updated
Hail is the damage people underestimate, because on the day it usually does not leak. A hailstorm passes, the roof looks dented but intact, and the consequences arrive one or two seasons later.
The failure mode is different on every covering, so it is worth knowing what to look for on yours.
On IBR and corrugated sheeting
Steel dents before it splits. A dented sheet is usually still watertight, and if the coating is unbroken it may run for years. The problem is where the impact fractured the coating: that spot rusts, and it rusts from a point rather than along an edge, so it perforates faster than general weathering would.
Hail also flattens washers and shocks fixings loose. After a serious hailstorm, a large share of the useful work is re-fixing rather than sheet replacement.
On concrete and clay tiles
Tiles crack rather than dent, and the crack is frequently hairline and invisible from the ground. Water then passes onto the underlay, which is fine if the underlay is sound and a disaster if it is thirty years old and brittle.
Hail also chips the surface of concrete tiles, exposing a more porous layer that soaks up water and holds it. This shows as tiles that stay dark long after the rest of the roof has dried.
On flat roofs and waterproofing
Hail bruises membranes. On a torch-on system the granular surface is stripped in patches, which removes its UV protection precisely where it was hit. That area then ages several times faster than the rest of the roof.
Any hail on a flat roof is also worth an outlet check, since the same storm typically washes debris into the drains.
Hail does not usually leak on the day. It sets a clock running at every point where the coating broke.
Documenting it properly
Hail damage is dispersed, which makes it hard to photograph convincingly from the ground. What helps is a set of close, well-lit photographs across several roof areas rather than one shot of the worst dent, plus a note of the date of the storm.
If you are claiming, that documentation is the claim. If you are not claiming, it is still the baseline for judging whether the roof deteriorates over the next two summers.
- Several areas, not just the worst spot
- Close enough to see coating fractures, not just dents
- Any chipped tile surfaces and displaced ridge caps
- Gutters, which catch granules washed off a hail-damaged membrane
What is worth doing now
Immediately after hail, the useful jobs are re-fixing loosened sheets, replacing tiles that are visibly fractured, clearing gutters and outlets of debris and granules, and re-coating any waterproofing whose surface protection was stripped.
Full sheet replacement based purely on cosmetic denting is rarely the right call unless the coating has been broken widely.