Remove Old Decramastic. Check For Asbestos. Install The New Roof.
Tell us about your roof and we’ll help confirm if asbestos testing, removal and replacement roofing should be included.
Auckland’s dedicated team for Decramastic roof conversion. Backed by Total Roofing’s decades of roofing experience and a WorkSafe NZ Class A asbestos removal licence, we convert old Decramastic roofs across Auckland into long-run COLORSTEEL® or modern pressed metal tile systems.
Decramastic roofs were common on New Zealand homes from the 1960s through to the 1980s. Many older Decramastic-style roofs may contain asbestos in the bituminous coating, mastic layer, underlay or related roof materials. Visual inspection alone cannot confirm this, so testing is the safest starting point before removal, repairs, restoration or re-roofing begins.
This matters because a Decramastic conversion can expose more than the visible tile. Once the old roof covering is lifted, asbestos-containing underlay or sarking may be found beneath. If asbestos is present, the job needs to be handled by a licensed asbestos removal team, not treated like a standard roof tear-off.
Once the old Decramastic roof is removed, the next question is what should replace it. We usually recommend one of three pathways depending on the property, roof structure, asbestos test results, budget and preferred appearance.
For many Auckland homeowners, the most straightforward Decramastic conversion is to remove the old pressed metal tile roof and replace it with long-run COLORSTEEL®.
This option gives the property a cleaner, simpler roofline and can suit homes where the owner wants a modern metal roof rather than another tile-style finish. Profile options may include corrugate, 5-rib, trapezoidal or tray-style roofing, depending on the home’s architecture, roof pitch and budget.
The conversion process can include asbestos testing where required, safe tile removal, underlay assessment, disposal, roof structure checks, new roofing underlay, long-run steel installation, flashings, ridge cappings and spouting integration.
Roof blanket insulation can also be discussed while the roof is open, especially where the existing roof has little insulation or where rain noise is a concern.
If testing confirms asbestos in the Decramastic tile coating, mastic, underlay or associated roof material, the conversion must be planned as an asbestos removal job, not a standard re-roof.
That can include WorkSafe NZ notification where required, controlled site setup, exclusion zones, wet-method removal, careful handling, waste wrapping, approved disposal and clearance documentation where required.
Once the asbestos-containing material has been removed and the roof area is prepared, the replacement roof can be installed. This may be long-run COLORSTEEL®, modern pressed metal tile or another specified roofing system suited to the property.
The key advantage is coordination. The asbestos removal and re-roofing stages are planned together, which helps avoid delays, handover gaps and surprise scope changes once the old tiles are lifted.
Many original Decramastic roofs installed across Auckland are now several decades old. Some are still performing reasonably well, but many are showing the same wear patterns: stone-chip loss, denting, corrosion, moss, lichen and failing fixings.
A roof assessment is important because some Decramastic roofs may be suitable for short-term maintenance, while others are better treated as a replacement project.
When researching Decramastic roof conversion in Auckland, you will usually come across two options.
The first is an overlay, where a new roofing system is installed over the existing Decramastic roof.
The second is full conversion, where the old Decramastic roof is removed, asbestos is tested and handled where required, and the new roof is installed over a clean, prepared structure.
We focus on full conversion because it gives the property owner a cleaner long-term result.
Overlay can leave the old roof and any asbestos-containing material in place. That may create issues later for repair work, solar installation, future re-roofing, insurance questions, due diligence or resale.
Overlay can also add weight to the roof structure because the old system remains underneath the new one. Whether that is acceptable depends on the building and the proposed system, but it should not be assumed.
The upfront saving can be real, but the long-term value is not always clear once future disclosure, structural condition and the eventual second re-roof are considered.
Overlay may be considered in limited cases, such as:
For most Auckland homeowners who want a clean long-term result, full conversion is usually the safer and more complete option.
We will explain the trade-offs at quote stage so you can make an informed decision.
A Decramastic conversion needs more care than a standard re-roof because there may be asbestos in the tile coating, old underlay or other hidden roof materials. Our process is built around clarity, safety and a proper handover.
Many Decramastic conversions involve more than one trade: asbestos testing, asbestos removal, roofing, scaffold, waste handling, clearance and new roof installation.
We coordinate the conversion under one plan. That helps reduce timing issues, handover gaps and confusion over who is responsible for each stage.
One Auckland team. One quote. One point of contact.
We do not assume a Decramastic roof is safe to disturb without checking the risk first.
Where asbestos is suspected, testing should be arranged before removal, repair or conversion work begins. This may include checking both the tile material and the underlay, because either can affect the removal process.
You should know what the job involves before work starts, not after the roof is already open.
Where we complete the replacement roof, our roofing workmanship is backed by a 5-year workmanship guarantee.
Manufacturer warranties may also apply to the selected roofing product, depending on the product, supplier, environment and installation requirements. These details are confirmed before installation and provided with your handover documentation where applicable.
We inspect the Decramastic roof, review access, check the roof condition and identify whether asbestos testing is required before removal or conversion begins.
Where asbestos is suspected, samples can be sent to an accredited laboratory for confirmation.
Your quote is prepared around the roof condition, test results where available, replacement option, access, scaffold requirements and any likely extras.
The quote can include conversion to long-run COLORSTEEL®, modern pressed metal tile or another suitable roofing system.
If licensed asbestos removal is required, WorkSafe NZ notification is lodged where required. The programme is then scheduled around notification periods, scaffold, material ordering and weather.
Neighbours may also be notified where required.
The work area is set up with appropriate safety controls. If asbestos is confirmed, the removal is carried out using licensed asbestos procedures.
Tiles are removed carefully and handled in a way that reduces breakage and unnecessary disturbance.
Once the tiles are lifted, the underlay is checked. If asbestos-containing underlay is confirmed or suspected, it is removed under the required controls and disposed of correctly.
This is one of the key reasons Decramastic conversion should be planned carefully before work begins.
The roof structure is inspected after the old roof is removed. Battens, purlins and roof framing are checked, and any visible issues are discussed before the new roof is installed.
Where required, affected areas are cleaned using suitable asbestos decontamination methods, including HEPA vacuuming where appropriate.
New roofing underlay is installed. Roof blanket insulation can also be added where suitable.
The selected replacement roof is then installed, whether that is long-run COLORSTEEL®, modern pressed metal tile or another specified system.
Clearance documentation is arranged where required for asbestos work. Flashings, ridge cappings, valleys, gutters, penetrations and roof edges are completed as part of the final roof system.
You receive relevant handover documents for your property records.
The table below gives guide ranges for Auckland properties.
| Scenario | Roof Area | Typical Total Cost | Timeframe |
|---|---|---|---|
| Conversion to COLORSTEEL® Endura, no asbestos confirmed | 130–180 m² | $18,000–$28,000 | 4–6 days |
| Conversion to COLORSTEEL® Endura, asbestos confirmed in tiles or underlay | 130–180 m² | $22,000–$34,000 | 5–7 days |
| Conversion to COLORSTEEL® Maxx, coastal site, asbestos confirmed | 130–180 m² | $25,000–$40,000 | 5–7 days |
| Conversion to modern pressed metal tile, asbestos confirmed | 130–180 m² | $28,000–$44,000 | 6–8 days |
| Garage or sleepout Decramastic conversion | 25–50 m² | $6,000–$14,000 | 1–2 days |
| Larger home or two-storey property | 200–280 m² | $30,000–$55,000 | 7–10 days |
Older Decramastic-style roofs may contain asbestos in the coating, mastic, underlay or related roof materials. This is more likely on roofs installed before the 1980s, but visual inspection cannot confirm it.
The only reliable way to know is laboratory testing. If the roof is going to be repaired, removed, restored or replaced, testing should be considered before work begins.
Some Decramastic roofs can be restored if they are still structurally sound and not heavily deteriorated. Restoration may include cleaning, coating or chip resurfacing, depending on the system.
However, restoration does not remove any asbestos-containing material if asbestos is present. It may extend the roof’s useful life, but it is not the same as full conversion or replacement.
If the roof is badly dented, rusting, leaking, shedding chip or asbestos is confirmed, full conversion may be the better long-term option.
We do not recommend overlay for most standard homeowner situations.
Overlay may reduce upfront cost, but it can leave old roof material and possible asbestos in place. It can also make future repairs, solar work, resale due diligence or eventual re-roofing more complicated.
Full conversion gives a cleaner result because the old roof is removed, the structure can be checked, and the new roof is installed over a prepared substrate.
Older Decramastic roofs and modern pressed metal tiles can look similar because both use a tile-style pressed metal shape.
The difference is in the materials, coatings, manufacturing standards and warranty systems. Modern pressed metal tiles are made using current roofing technology and asbestos-free product systems.
People sometimes use “Decramastic” as a general term for stone-chip metal tile roofing, but original older Decramastic systems should be treated separately and assessed before removal or conversion.
In many cases, yes. The work area is controlled during removal, and the roof is managed carefully during the replacement stage.
Some families choose to be away during the noisiest or most disruptive parts of the work. We will explain what is practical and safe for your property before the job begins.
A standard Auckland home may take around 5–7 working days once site work begins, depending on roof size, access, asbestos test results, weather and replacement material availability.
Larger homes, steep sites, two-storey properties or pressed metal tile conversions may take longer. Material lead times should also be allowed for before work starts.
Insurance may contribute if the roof has been damaged by an insured event such as storm, hail, fire or a fallen tree.
Coverage depends on your policy, the cause of damage, the condition of the roof before the event and the insurer’s assessment. Do not assume full replacement is covered until your insurer confirms it.
We can provide photos, an inspection report and an itemised quote if supporting documentation is needed.
Depending on the job, your documentation may include asbestos test results, WorkSafe NZ notification records where required, hazardous-waste disposal records, air monitoring results where applicable, clearance documentation, product warranty information and workmanship guarantee details.
Keep these documents with your property records. They can be useful for future insurance, renovation, due diligence or sale.
Decramastic conversion often involves both roofing and asbestos risk. Splitting the work across separate contractors can create delays, handover gaps and confusion over who is responsible for each stage.
A coordinated approach helps align testing, removal, disposal, roof preparation, new roof installation and handover documentation.
The hardest part of a Decramastic conversion is knowing what is actually under the roof.
We can help assess the roof, confirm whether asbestos testing is needed, explain the replacement options and provide an itemised quote for the full conversion.