Gauteng summer storms damage roofs through three combined forces: gusty winds that lift and tear away coverings, hail that cracks and bruises materials, and heavy rain that overwhelms gutters and municipal drains. After a storm, check for missing tiles or sheets, cracked or bruised roofing, blocked gutters, and ceiling stains, since drainage failures often turn a single downpour into weeks of hidden water damage.
TL;DR:
- Common roof anchors on solid brick walls may fail at peak winds of roughly 27 to 32 metres per second, sometimes after masonry cracks.
- SANS guidance sets hail resistance at 10 joules for roofing sheeting, rising to 20 joules in severe hail areas, including much of Gauteng.
- Flat roofs should meet minimum falls of 1:80 or 1:50, and pooling that remains more than a day signals inadequate drainage.
- Solar panels can develop microcracks invisible from the ground, so visual checks alone cannot confirm that hail left them undamaged.
- After a storm warning, wait until SAWS lifts the alert before inspecting, and call a licensed contractor rather than walking on a wet roof.
Table of Contents
- How strong winds damage roofs
- Hail and impact damage: what materials are most at risk
- Heavy rain, ponding and drainage failure: how water finds a way in
- Vulnerabilities by roof type and detail
- Practical maintenance and immediate post-storm checklist for Gauteng homeowners
- Expert perspective from Eben and region-specific takeaways
- Why urban drainage and community reporting matter
- How we help after storms
- FAQ
- Sources
How strong winds damage roofs
Steady wind pushes against a roof, but gusts create suction that pulls upward on the covering itself, a mechanism closer to an aircraft wing than a wall being shoved. This uplift concentrates at ridges, eaves and hips, where turbulence is worst, which is why damage so often starts at the roof’s edges rather than the middle.
Anchorage is the weak point in many Gauteng homes. Research into roof anchor performance found that common anchor systems on solid brick walls can fail at peak wind speeds of roughly 27 to 32 metres per second, often with masonry cracking appearing before the anchor pulls out entirely.
27 to 32 m/s is the range at which common roof anchorage methods may fail, which means a roof that looks structurally sound can still lose its grip during a severe summer squall.
Typical wind-failure modes include:
- Flashings torn away at ridges, valleys and chimney junctions.
- Tiles lifted or dislodged where fixings have weakened over time.
- Fixing straps pulling loose from masonry, sometimes with visible wall cracking.
- Progressive loss of coverings once one section fails and exposes the next.
- Secondary damage from debris, branches and loose items thrown against the roof.
Hail and impact damage: what materials are most at risk
Hailstones carry kinetic energy that varies with size and fall speed, and SANS roof design guidance sets a baseline hail-resistance expectation of 10 joules for roofing sheeting, rising to 20 joules in areas known for severe hailstorms, which includes much of Gauteng.
Materials respond differently to impact:
- Concrete and terracotta tiles tend to crack or chip rather than puncture, but a cracked tile lets water through long after the storm passes.
- Metal sheeting can show dents, or “bruising”, that weakens the protective coating and invites rust.
- Waterproofing membranes on flat roofs can tear or thin under repeated impact.
- Solar PV modules may suffer microcracks that are invisible from the ground; extreme weather often requires more than a visual check to confirm a panel is undamaged.
Visible cracking or dented sheeting always warrants a closer inspection, since hail damage frequently hides a slower, structural problem behind a minor-looking surface mark.
Heavy rain, ponding and drainage failure: how water finds a way in
Water does not need a dramatic storm to cause damage. It needs somewhere to collect. SANS guidance specifies minimum falls for flat roofs, either 1:80 or 1:50 depending on how many interruptions the roof surface has, with outlets positioned away from upstands and expansion joints specifically to prevent ponding.
When falls are too shallow or outlets are badly placed, water sits rather than drains, and sitting water finds every weak seam eventually.
- Check that gutters and downpipes are clear before the summer season starts.
- Watch for water pooling on flat sections more than a day after rain, a sign the falls are inadequate.
- Look for staining at eaves and parapets, which often signals backflow from blocked drains rather than a roof leak itself.
- Report blocked municipal stormwater drains promptly, since urban flooding in South Africa is frequently worsened by drain blockages that force water back into properties rather than away from them.
Pro Tip: Keep dated photographs of any pooling water or blocked drain you report. They make a far stronger insurance or municipal case than a description alone.
Vulnerabilities by roof type and detail
Different roof types fail in different places, so knowing your roof’s weak points speeds up any inspection.
- Tile roofs: broken tiles, failing ridge mortar and uplift at hips and valleys are the usual culprits; an intact under-tile membrane often prevents a cracked tile from becoming an indoor leak.
- Metal sheeting: loosened screws, corroded fixings, inadequate overlaps between sheets and punctures from wind-blown debris are the common entry points for water.
- Flat roofs: insufficient falls, clogged outlets, membrane tears and failed parapet upstands allow water to pond and seep rather than drain.
- Trusses and anchors: uplift forces transmit straight through the roof structure to the supporting walls, and anchor pull-out can show up first as a crack in the masonry below rather than an obvious roof problem.
Practical maintenance and immediate post-storm checklist for Gauteng homeowners
Most storm damage is manageable when caught early. A short list of seasonal tasks, paired with calm post-storm actions, protects both the roof and any insurance claim that follows.
Before the storm season:
- Clear gutters and downpipes of leaves and debris.
- Trim overhanging branches that could snap onto the roof in strong wind.
- Secure loose items on or near the roof, including satellite dishes and aerials.
- Check ridge mortar and tile fixings for early signs of looseness.
After a storm:
- Photograph any visible damage before clearing debris.
- Avoid walking on a wet or damaged roof; leave access to a professional.
- Fit a temporary tarpaulin over any active leak to limit interior damage.
- Log blocked municipal drains with your local authority and keep a record of the report.
Pro Tip: Never inspect a roof during or immediately after a storm warning. Wait for SAWS to lift the alert, then call a licensed contractor if anything looks off. Our inspection checklist for South African buildings covers what to look for room by room.
Expert perspective from Eben and region-specific takeaways
We find that the retrofits that prevent the most repeat damage are often the least visible ones: undertile membranes that catch water a cracked tile lets through, resealed membrane seams on flat roofs, and properly re-secured fixings at ridges and hips where uplift concentrates first.
When we inspect a roof after a storm, we check outlet flow capacity, membrane integrity and fixing security before anything cosmetic, because a roof can look fine from the ground while losing its grip underneath. Our installation guide for Gauteng homes sets out the detail behind these checks.
A roof that survives one severe storm season on luck alone rarely survives the next one on the same luck.
— Eben
Why urban drainage and community reporting matter
A roof’s defences only go so far when the street outside cannot drain. Upstream development, blocked municipal stormwater systems and encroachment on drainage servitudes all push more water towards individual properties than their gutters were ever designed for.
Reporting blocked drains and keeping a written record of municipal responses, as outlined in cases where residents have pushed multiple state entities to fix failing infrastructure, strengthens the case for repairs long before the next storm arrives.
How we help after storms
A storm-damaged roof rarely needs guesswork, it needs someone who can tell the difference between a cosmetic mark and a structural risk. We offer waterproofing for roofs, basements, bathrooms, foundations and concrete decks across residential, commercial and industrial properties, which covers the membrane repairs, gutter and outlet remediation, and inspection reports that follow most Gauteng storms.
We think licensing, demonstrated experience and a written warranty matter more than price when choosing who fixes a roof, since a cheap repair that fails in the next storm season costs more than the quote ever saved. Our guide to assessing waterproofing needs helps you work out what to prioritise before you call anyone.
If a recent storm has left you with stains, loose tiles or pooling water, request a quote through our waterproofing services page and we will talk you through an inspection.
FAQ
What causes flooding and what impact does it have on roofs?
Flooding is caused by heavy rainfall combined with insufficient drainage, whether that is blocked gutters on a roof or overwhelmed municipal stormwater systems in the street outside. On a roof, the impact is ponding, seepage at eaves and parapets, and in severe cases structural rot where water sits for extended periods.
What does wind damage on a roof actually look like?
Wind damage typically shows as missing or lifted tiles, torn flashings, and in severe cases, fixing straps pulled loose from the supporting walls. Studies on roof anchorage show failures can begin at wind speeds of roughly 27 to 32 metres per second, often with masonry cracking first.
How does wind actually lift roofing materials off during a storm?
Gusting wind creates suction above the roof surface rather than simply pushing on it, pulling tiles and sheets upward from underneath where fixings are weakest. This uplift effect concentrates at ridges, eaves and hips, which is why damage usually starts at those edges rather than the centre of the roof.
How severe can flooding get in South Africa?
Flooding severity varies by region and storm, and SAWS regularly issues warnings for heavy rain, hail and damaging winds that lead to localised flooding and infrastructure damage, including in Gauteng. A December 2025 severe thunderstorm event in Gauteng produced heavy rainfall, large hail and strong winds that caused rapid flooding and roof damage.
When should I call a professional after storm damage?
Call a professional as soon as you notice cracked tiles, dented metal sheeting, pooling water on a flat roof, or ceiling stains, since surface damage often hides a larger structural issue. If you are dealing with active water intrusion, a restoration specialist can handle emergency dry-out while a roofing inspection addresses the source.
Sources
- SAnews — SAWS warns of heavy rain, severe thunderstorms and hail
- SANS 10400-B / SANS roof design guidance (extract)
- UJ research paper on roof anchor performance under South African wind climate