Old Corrugated Roof Replacement Wellington

By the Metal Roofing Solutions team
Published 9 July 2026 · Wellington re-roofing guide and project example

If an older corrugated roof is weathered, leaking or reaching the point where repairs are becoming frequent, the next step is a proper roof assessment—not another guess from the ground. The existing sheet material, roof condition, access, junctions and any asbestos risk all need to be understood before a reliable replacement quote can be prepared.

The photographs on this page show a genuine Wellington re-roof completed by our team. They record the ageing corrugated roof before work and the finished silver long-run metal roof. A photograph cannot confirm whether the original material contains asbestos. Testing may therefore be needed before removal is priced, and the roofing quote should set out the work it actually covers.

This Wellington re-roof at a glance

Before: what an ageing corrugated roof can tell us

The before photograph shows extensive surface weathering across the foreground roof, along with staining on other corrugated sheets and several transitions between roof areas. That is useful information for planning an inspection, but it is not enough to diagnose every defect or identify the roofing material.

When we assess an older roof, we look beyond the most obvious sheet. The valleys, ridges, edges, fasteners, penetrations, gutters and changes between adjoining roofs can be just as important as the main covering. We also need to consider whether the sheets remain safe to access. WorkSafe notes that roofing can become brittle through its material, age or weathering, and that no one should access a brittle roof until suitable controls are in place.

For homeowners, the safest first inspection is from ground level. Do not climb onto a weathered roof to obtain a closer photograph or sample.

Could an old corrugated roof contain asbestos?

Possibly—but appearance is not proof. WorkSafe’s asbestos guidance for homeowners says materials containing asbestos can look identical to materials that do not, and the only way to confirm asbestos is through proper sample testing. WorkSafe also identifies asbestos cement roof sheeting and ridge capping as materials found in some older New Zealand buildings.

If asbestos is suspected, treat the material cautiously until it has been assessed. Do not drill, cut, sand, scrape or water-blast it. Those actions can disturb the surface and release fibres if asbestos is present. Sampling should be arranged through a reputable asbestos contractor rather than attempted as a DIY job.

The roofing photograph on this page has not been used to diagnose asbestos. A laboratory result or suitable asbestos survey is what should inform the removal plan and quotation.

What happens if asbestos is confirmed?

A positive result changes how the existing roof is handled; it does not prevent the building from receiving a new metal roof. The removal scope should be based on the material type, condition, quantity and site access. It should identify the appropriately qualified asbestos contractor, controls for people nearby, removal and disposal arrangements, clearance requirements where applicable, and how the building will be kept protected while the new roof is installed.

The roofing and removal scopes need to connect. A quote that covers only the new sheets but leaves testing, removal, temporary weather protection or disposal unclear is not yet a complete project price. If you already have a laboratory or survey report, include it with your roofing enquiry so it can be considered from the start.

What affects the cost of replacing an old corrugated roof?

There is no useful fixed price based on the photograph alone. These are the main items we would expect a property-specific quote to consider:

• Roof area and layout: multiple planes, valleys, ridges and changes in height add labour and detailing.
• Existing material: confirmed or suspected asbestos requires a different removal plan from ordinary metal roofing.
• Condition and strength: brittle sheets and questionable support areas affect how the roof can be accessed.
• Scaffolding and edge protection: safe access is part of the job, not an optional extra.
• Removal and disposal: the quote should state who is responsible and what is included.
• Roofing specification: profile, metal substrate, coating, thickness, fasteners and flashings should suit the address.
• Junctions and drainage: valleys, gutters, penetrations and adjoining roof areas need to work as one system.
• Concealed repairs: the process for documenting and approving unexpected work should be clear.
• Weather planning: Wellington wind and rain influence the work sequence and temporary protection.

A low initial number can become expensive if major items are missing. Compare quotes by scope, exclusions and responsibilities—not just the total on the last page.

After: the completed long-run metal roof

The completed photograph shows long-run metal sheets across the connected roof planes, together with the ridges, valleys and edge flashings that bring the finished roof together. The scaffolding also makes the access required for a multi-plane re-roof easy to see.

A new roof should not be judged on appearance alone. The written specification, compatible fasteners and flashings, installation details, drainage, completion information and maintenance requirements are what establish what has been supplied.

What should a complete re-roofing quote include?

• the roof areas and components included in the scope;
• whether asbestos testing or a survey is required before pricing can be finalised;
• who is responsible for any asbestos removal, clearance and disposal;
• scaffolding, edge protection and access arrangements;
• removal and disposal of the existing roofing;
• the proposed profile, metal, coating, thickness, colour and fasteners;
• underlay, supports, valleys, ridges, flashings and penetrations;
• gutters, downpipes and adjoining roof areas included or excluded;
• temporary weather protection and the expected work sequence;
• how concealed damage and other variations will be approved;
• consent, design and documentation responsibilities;
• cleanup, completion records, product information and warranty conditions.

WorkSafe’s roof guidance identifies falls as the most serious roof-work hazard and says suitable protection should be used when roof cladding is replaced. The scaffolding visible in the project photographs is therefore part of understanding the real scope—not simply a background cost.

Does replacing corrugated roofing need building consent?

Some roof replacement work can be exempt, but the actual scope matters. MBIE’s Schedule 1 guidance gives replacement of older profiled-metal roof cladding with comparable profiled metal in the same position as an example that may be exempt, provided the conditions are met.

Structural work, a material or design change, a premature durability failure, specified systems or other project details may change the answer. All work still needs to comply with the Building Code. Confirm the proposed scope with the relevant council rather than assuming every re-roof is the same.

Frequently asked questions

Can a roofer tell whether corrugated sheets are asbestos from a photo?

No. A photograph can help identify material that should be assessed, but WorkSafe says testing is the only way to confirm asbestos. Do not take the sample yourself.

Should I repair or replace an old corrugated roof?

That depends on whether the problem is localised or spread across the roof, the condition and safety of the sheets, the junctions and supports, and the likely cost of future maintenance. An inspection should separate a repairable defect from a roof-wide problem.

Can I clean or water-blast a suspected asbestos roof?

No. WorkSafe advises that suspected asbestos should not be disturbed and specifically identifies water blasting as an activity that can release fibres.

Can the asbestos removal and new roof be priced together?

They can be planned as one connected project, but the responsibilities must be clear. Testing results, the removal scope, access, temporary protection and new-roof installation should all be accounted for.

How long does an old-roof replacement take?

Timing depends on roof size and complexity, testing and removal requirements, scaffolding, weather and any repairs discovered after removal. A useful quote should give a proposed sequence rather than an unsupported universal timeframe.

Request an old-roof replacement assessment

If you are considering an old corrugated roof replacement in Wellington, Lower Hutt, Upper Hutt, Porirua or the Kāpiti Coast, send us:

• the property address;
• the approximate building or roof age, if known;
• safe ground-level photographs of the roof and access;
• details of leaks, repairs or known problem areas;
• any existing asbestos test or survey report.

We can then discuss the sensible next step and what information is needed for a property-specific roofing scope. You can also review our metal roofing and re-roofing service or the related Wellington tile-to-metal conversion guide.

Request a roofing assessment or call 022 155 3184.