How to Seal Leaking Metal Roof Screw Holes in Ghana (2026)
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To stop a metal roof leaking at the screw holes, fix the screw first and seal second: replace perished washers, re-drive loose or overtightened screws, and then cover each fixing with a 10 cm square of butyl leak seal tape on clean, dry metal. One GHS 250 roll of 10 cm × 5 m tape gives about 50 patches. If the sheets are rusted through, replace them instead.
Why screw holes leak
- Perished washers. The rubber washer under the screw head hardens and cracks under a UV index of 11+ and daily heating. Once it cracks it no longer seals.
- Overtightening. A screw driven too hard splits the washer and dimples the sheet so water collects around it.
- Screws in the valley. Fixings should go through the crest (the high rib). Screws in the pan sit in running water every storm.
- Old holes left open. When a roof is re-fixed, the old nail or screw holes are often left. They leak just like a failed screw.
- Thermal movement. Metal sheets expand and contract with the 20°C daily swing. Over years this elongates holes.
Step-by-step repair
- Find the leaking fixings. From inside on a sunny day, look for pinpoints of light. Mark them. From outside, look for rust tails below screw heads.
- Fix the screw. Replace any screw with a cracked or missing washer. Re-drive loose screws until the washer just compresses — not flat. Move valley screws to the crest where possible.
- Clean. Wire-brush rust, wipe off dust, and let the metal dry. Tape will not hold on dust or damp metal.
- Tape. Cut 10 cm squares of Leak Seal Tape (GHS 250). Press each one over the screw head and roll or press hard from the centre out so there are no air channels.
- Spray where tape won't sit. Around awkward ridge caps or bent flashings, Waterproof Leakage Spray (GHS 200) can seal hairline gaps.
- Open holes. Old empty holes get a tape patch too.
Which product for which leak
| Leak point | Best product | Price |
|---|---|---|
| Individual screw heads, open nail holes | Leak Seal Tape, 10 cm patches | GHS 250 per roll (~50 patches) |
| Sheet side-laps and end-laps | Leak Seal Tape in a continuous strip | GHS 250 per 5 m |
| Hairlines around flashings, ridge caps | Waterproof Leakage Spray | GHS 200 |
| Box gutter on metal roof | Fleece-reinforced PU (professional job) | GHS 180-280/m² installed |
When tape is the wrong answer
If the sheet is rusted through around many fixings, or there are rust holes between fixings, taping every hole is spending money on a roof that needs new sheets. Replace the affected sheets. Likewise, if the leak is at a box gutter rather than the sheet, the gutter needs its own lining — see metal roof gutter waterproofing.
Safety
Walk only on the purlin lines, never mid-span between purlins. Don't work on a metal roof in the middle of the day: the surface can be too hot to touch. If the roof is high or steep, get help.
Need a professional?
We handle metal roof re-fixing, lap sealing and gutter lining across Ghana. Installed polyurethane work carries a 3-year workmanship warranty plus a 3-year manufacturer material warranty, with a 20-year design life. Book an inspection or call 0555 548 001.
Related Resources
- IBR roof leakage repair
- How to apply leak seal tape
- Rubber tape for roofing
- Warning signs your metal roof gutter is failing
- Flex seal tape vs butyl rubber tape
Fest Ghana Limited is the trading name of FGL Waterproofing Solution Limited Company, a company registered in Ghana — Registration No. CS218171026. Company information.