Why a “Tin” Roof Won’t Turn Your Lounge into a Drum or an Oven
If you’ve ever told the oke at Builders that you fancy a Chromadek® roof and he replied, “Sho, enjoy the racket when it rains,” this post is for you.
South Africans love a good urban legend—like biltong curing better during load-shedding or metal roofs drumming louder than Uncle Piet’s garage band. Today we put two of the loudest myths—noise and heat—under the microscope and prove why a 2025 steel roof is more comfort-king than clatter cannon.
Myth #1 – “Metal roofs are deafening in Gauteng thunderstorms”
The Truth
Lab tests show rain on bare metal registers ± 52 dB, just 6 dB louder than asphalt shingles—and that’s before any ceiling board or insulation is added. Add a standard mineral-wool blanket and the drumming drops a further 10–15 dB, pulling it comfortably below conversational chatter
Reality check: Your neighbour’s tiled roof may sound quieter because the ceiling is already stuffed with glass-wool. Give steel the same treatment and the difference becomes virtually unnoticeable.
Quick Noise-Taming Tips
- Install a 135 mm mineral-wool or polyester blanket (SANS 10400-XA compliant) between purlins and sheet.
- Use bonded EPDM storm-washers—they dampen vibration where screws meet steel.
- Opt for concealed-fix profiles (e.g., Klip-Lok): no exposed screws = fewer vibration paths.
Use bonded EPDM storm-washers—they dampen vibration where screws meet steel.
Opt for concealed-fix profiles (e.g., Klip-Lok): no exposed screws = fewer vibration paths.
Myth #2 – “Metal roofs turn homes into ovens”
The Truth
Modern Chromadek® and Colorplus® coatings use heat-reflective pigments that boost Total Solar Reflectance (TSR) by up to 20 %—especially in darker colours. “Cool-roof” research shows reflective coatings can lower roof-surface temps by 10–25 °C and cut summer energy use by as much as 15 %.
Pair the coating with SANS-approved ceiling insulation and indoor temps stay as civilised as a Pretoria springbok-burger joint.
Heat-Hack Checklist
| Hack | Typical °C Drop | Cost Impact |
|---|---|---|
| Light or TSR-enhanced colours | 3–7 °C | None (same sheet price) |
| 135 mm glass-wool blanket (R-3.5) | 6–10 °C | R35–R45/m² |
| 40 mm foil-faced PIR board + blanket | 8–12 °C | R80–R110/m² |
| Whirly-bird ventilators (2 per 100 m²) | 2–4 °C | R2 k–R3 k each |
Myth #3 – “Hail will make the roof rattle like a marimba”
The Truth
Hail noise is mostly impact-energy, not sheet thickness. A thicker 0.53 mm IBR panel plus under-sheet blanket soaks up percussion, while deeper ribs deflect hailstones better than flat tiles. In practice, the interior sound difference is marginal—and your steel roof will be intact when the storm clears.
Myth #4 – “Insulation is optional on metal roofs”
The Truth
Energy regs (SANS 10400-XA) mandate minimum R-values for Gauteng ceilings—metal or tile. Skipping insulation isn’t just noisy and sweaty; it’s illegal when you sell or insure the house.
Translation: You’re fitting insulation anyway; add 15 % more density and noise & heat myths evaporate.
Bonus Bust – “Lightning loves metal roofs”
Lightning chases height and conductivity—not brand logos. A metal roof actually dissipates strikes safely when bonded and earthed, reducing fire risk versus combustible tiles.
The Take-Home Playbook
- Specify reflective Chromadek® or Colorplus® in Highveld-friendly colours.
- Hit or exceed SANS R-values with mineral-wool or foil-faced board.
- Seal the deal with storm-washers, ridge insulation and proper earthing.
Hit or exceed SANS R-values with mineral-wool or foil-faced board.
Seal the deal with storm-washers, ridge insulation and proper earthing.
Do that, and your steel roof will be as hushed as a library—and cooler than a Soweto shisanyama on Heritage Day.
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