Metal roofs creak and pop because the metal sheets expand when they heat up and contract when they cool down — a completely normal process called thermal movement. In New Zealand's variable climate, where a roof can swing from cold overnight temperatures to intense summer sun, this movement can be significant. The good news is that most creaking can be reduced or eliminated with the right approach.
Why Does Thermal Expansion Cause Noise?
When metal heats up, it expands; when it cools, it contracts. If any part of the roofing system restricts that movement — an over-tightened fastener, a poorly fitted flashing, or a purlin that grips the sheet too firmly — the metal is forced to flex suddenly rather than slide smoothly. That sudden flex is what you hear as a creak, bang, or tick.
Common culprits include:
- Over-driven or incorrectly spaced screws that clamp the sheet too tightly
- Flashings that are sealed or fastened in a way that prevents movement
- Roof sheets rubbing against each other at overlaps or ridges
- Purlins or battens that have warped and are gripping the sheet unevenly
- Lack of insulation or underlay allowing rapid temperature swings
Check Your Fasteners First
The most common DIY-accessible fix is inspecting your roofing screws. Metal roofing screws should be driven to the correct torque — tight enough to compress the neoprene washer and seal the hole, but not so tight that the sheet cannot move laterally. Over-driven screws are a leading cause of creaking.
If you can safely access your roof (see the safety note below), look for:
- Screws that have crushed the washer flat
- Screws in the flat of the pan rather than the correct fixing position specified by the manufacturer
- Missing or cracked washers that allow metal-on-metal contact
Replacing over-driven screws with the correct type and torque can make a noticeable difference. Always use screws rated for your specific roofing profile and material (e.g., Colorsteel, Zincalume, or aluminium).
Use Thermal Movement-Friendly Fixings
For longer runs of roofing (generally over 6 metres), slotted or sliding fixings are used to allow the sheet to move without restriction. If your roof was installed with standard fixed screws on long runs, this could be the root cause. A qualified roofer can retrofit appropriate fixings or re-fix sheets with the correct allowances.
Check that ridge caps and flashings are fixed at one end only (or with a sliding detail at one end), allowing the sheet beneath to move freely. Flashings that are rigidly sealed at both ends will fight against the roof sheet and cause noise.
Address Rubbing at Overlaps and Ridges
Where sheets overlap or meet at the ridge, metal-on-metal contact can cause squeaking. A roofer can apply a compatible butyl or foam closure strip between layers to cushion the contact point. Do not use standard silicone sealant here — it will bond the surfaces together and make the problem worse.
At the ridge, check that the ridge cap is not clamping the sheets too tightly. There should be a small amount of play to allow movement.
Improve Insulation and Underlay
One of the most effective long-term solutions is reducing the rate of temperature change the roof experiences. A quality sarking underlay or rigid insulation board beneath the metal slows down heat gain and loss, meaning the metal expands and contracts more gradually and quietly.
The BRANZ Good Practice Guide for metal roofing recommends appropriate underlays for thermal and acoustic performance. Under the **NZ Building Code (including weathertightness requirements) and general moisture management requirements, underlay also plays an important role in moisture management, so upgrading it can deliver multiple benefits.
Products like foil-faced blanket insulation or rigid PIR board are commonly used under metal roofing in New Zealand. Check with your supplier or a roofer for what suits your specific roof profile and pitch.
Check for Structural Movement
Occasionally, creaking is not just the roof cladding but the roof structure itself — purlins, rafters, or trusses moving slightly. If the noise is deep and structural-sounding rather than a surface tick or pop, have a licensed building practitioner inspect the framing. Structural issues are outside DIY territory.
For guidance on what work requires consent, refer to MBIE Building Performance and always confirm with your local council, as Schedule 1 exemptions vary.
Safety Note
Working on a roof carries serious fall risks. WorkSafe NZ requires appropriate fall protection for any roof work. Unless you are confident, have the right equipment (harness, anchor points, scaffolding or edge protection), and the roof pitch is safe to walk on, leave roof access to a professional. You can read more about safe working at height at WorkSafe NZ.
When to Call a Professional
Call a qualified roofer if:
- The noise is loud, persistent, or getting worse
- You suspect fasteners are failing or sheets have lifted
- The roof is steep, high, or otherwise unsafe to access yourself
- You need flashings re-done or sliding fixings retrofitted
- You want insulation or underlay installed properly
A professional roofer can diagnose the exact cause quickly and carry out fixes that will last. You can find experienced local roofers on tradedirectory.co.nz.
Roofing Association of NZ (RANZ)
Licensed Building Practitioner (LBP)
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