How the hidden clips work
A roofer screws clips to the battens or purlins, then locks each sheet down over them. On the 700 Hi-Strength version the clips go on with hex head screws. With nothing fixed through the pans, there are no screw holes for water to find on a roof where it drains slowly.
The Hi-Strength side laps are shaped to stop water being drawn sideways between sheets, which Lysaght calls an anti-capillary lap. That detail is what lets it go so flat.
Klip-Lok is a Lysaght trade mark, and Lysaght is part of BlueScope. We're independent of both and simply quote their published guides.
Which Klip-Lok?
| 406 | 700 Classic | 700 Hi-Strength | |
|---|---|---|---|
| Cover width | 406 mm | 700 mm | 700 mm |
| Rib height | 41 mm | 40 mm | 43 mm |
| Lowest slope | 1 degree | 1 or 2 degrees, depending on thickness | 1 degree at 0.48 mm, 2 degrees at 0.42 mm |
Where it helps, and what to watch
| Why it helps | What to watch | |
|---|---|---|
| Pitch | Works where corrugated's 5 degree minimum rules corrugated out | 1 degree is a minimum, not flat; the roof still needs a fall |
| Fixings | No screws through the sheet | Lysaght prefers supports 1500 mm or more apart and warns close spacing needs care with alignment |
| Sheet length | Lysaght can roll sheets on site, so long runs need no expansion joints | A long, low run sends a lot of water to one gutter |
| Insulation | The Hi-Strength clip leaves room for up to 100 mm under the sheet | Ask what thickness the quoted clip allows |
| Rib ends | Stop-ends or infill strips keep out dust, insects, birds, embers and wind-driven rain | Lysaght recommends them in severe environments, so check they're quoted |
Spans, thickness and drainage
For the Hi-Strength version, Lysaght's longest internal span between supports is 2200 mm at 0.42 mm BMT (base metal thickness) and 2800 mm at 0.48 mm, against 1200 mm for corrugated at 0.42 mm. The building code's standard recipe is tighter: the 2022 edition caps concealed-fix internal spans at 2100 mm and wants a clip at every rib. If your state now uses the 2025 edition, that limit may read differently.
Drainage is the other limit. Lysaght publishes the longest ridge-to-gutter run for each pitch, and at a rainfall intensity of 200 mm an hour, Hi-Strength can run 172 m at 1 degree and 312 m at 5 degrees. Houses don't come close, so on a home the weak point is the gutter or box gutter at the low end. Ask the roofer to size it for your area.
In bushfire areas
Stop-ends matter even more here. An NSW RFS guide to upgrading existing homes says gaps over 3 mm should be sealed or covered with mesh of no more than 2 mm aperture, in corrosion resistant steel, bronze or aluminium. It's an older guide that references the bushfire standard AS 3959-2009, so check today's rules for your Bushfire Attack Level (BAL) with your council.
On Colorbond or Zincalume, ask which mesh metal suits, because BlueScope says stainless steel shouldn't be used with its coated steel.
Before you sign
- Which Klip-Lok version and thickness are you quoting, and what's the actual pitch?
- Do my existing supports suit the clips, or do battens need changing?
- Will you fit stop-ends or infill strips at the rib ends?
- How is the low end drained, and how was the gutter sized?
Your part, and the roofer's
You can
- After heavy rain, look from a window or the ground for water lying on the roof or spilling over the gutter
- Keep the low-end gutter clear if you can reach it safely from a ladder
Leave to a roofer
- Walking on it, in the pans only, as Lysaght directs
- Fixing clips, sheets, stop-ends and flashings
When we'd pick it
We'd choose Klip-Lok when the pitch is too low for corrugated, or when you want a clean, screw-free look on a skillion. On an ordinary pitched house, corrugated or a ribbed profile does the same job just as well. If you go with Klip-Lok on a roof under 2 degrees, we'd check the quote says 0.48 mm Hi-Strength, with stop-ends at every rib.
Want a roofer to take a look?
Tell us the job and your postcode. We match it with a Find My Roofer certified roofer who specialises in that kind of work, and they call you to quote. Your number goes to them alone.