A useful new roof estimate should show what is being installed, what work is included and what could change the final cost. The lowest total may leave out removal, replacement of damaged roof decking, flashings or disposal, while a higher estimate may include a more complete scope. Ask each roofer to assess the property and provide an itemised written estimate based on the same requirements. Then compare the materials, installation details, exclusions, allowances, warranty terms and process for approving extra work. This makes it easier to budget realistically and reduces the risk of a disagreement once the old roof is removed.
An estimate should give you enough detail to understand the proposed work and compare it with other offers. It should identify the property, describe the roof area or sections involved, specify the proposed roofing materials and set out the work the contractor will carry out. It should also show the estimated total, whether GST is included, and any assumptions that affect the price.
Ask whether the document is an estimate or a firm quote, and how long its pricing is valid. Contractors may use these terms differently, so don’t rely on the label alone. Find out which parts of the price can change, what conditions could trigger a variation and whether you must approve extra work in writing before it proceeds.
A site inspection is particularly useful for a replacement. Roof shape, pitch, access, existing layers and signs of water damage can affect labour and materials. If an estimate is prepared without inspecting the roof, ask what information it is based on and which parts of the scope remain provisional.
Look for a clear description of each major part of the job. The estimate does not need to use identical wording to another contractor’s document, but you should be able to confirm whether the same work and materials are being priced.
| Estimate item | What to look for | Why it matters |
|---|---|---|
| Roofing material | Material type, profile or product, finish and relevant installation details | Broad labels can hide differences in the specified product or system. |
| Removal and disposal | Whether existing roofing will be removed, how many existing layers are assumed, and whether disposal is included | A low total may exclude removal or assume conditions that have not been confirmed. |
| Underlay and supporting components | Whether underlay and other specified components are included, and what will happen if existing parts need attention | These items can form part of the proposed roofing system and should not be left vague. |
| Flashings and roof details | Work around ridges, valleys, edges, penetrations and junctions with walls or other roof sections | These details need to be accounted for, not treated as an unexplained extra later. |
| Repairs and allowances | Any provisional amount or assumption for damaged timber, decking or other concealed problems | An allowance is not necessarily a fixed price for work that cannot yet be inspected. |
| Access and site protection | How the contractor will access the roof and protect the property and surrounding areas | Site conditions can affect what equipment and preparation the job requires. |
| Clean-up and disposal | Removal of roofing debris and the condition in which the work area will be left | Confirming this avoids different expectations at the end of the project. |
| Tax and total | The currency, whether GST is included, and the total amount payable for the stated scope | A headline figure is hard to compare if tax treatment or included work differs. |
Use the table as a prompt for questions rather than assuming every roof needs the same components. Ask the contractor to explain what is appropriate for your roof and to identify any item that is not included. If a line says “as required” or “to be confirmed”, find out how the decision will be made and how the additional cost will be calculated.
Roofing estimates often cannot confirm the condition of every part of the structure until the existing covering is removed. A contractor may therefore include an allowance for repairs or state that some work is excluded. That can be reasonable, but the estimate should explain the process: how damage will be documented, how the price will be agreed and who must approve the work.
Ask for examples of what the allowance covers and what would fall outside it. Check whether the estimate includes temporary protection if unexpected damage is found, and how the contractor will communicate any delay or change in scope. A clearly described provisional item is easier to manage than a vague promise that “repairs may cost extra”.
Two estimates can use the same broad material category while specifying different products or installation systems. Ask each contractor to name the proposed product or describe its relevant characteristics, including profile, finish and the components required for installation. For tile roofing, clarify the tile type and any associated work; for metal roofing, ask what product and finish are proposed. The specific details should suit the roof design and the manufacturer’s requirements.
Don’t compare material price alone. A roofing system may include underlay, fixings, flashings and other components, and the estimates may differ in what they include. Ask whether the quoted product is suitable for the roof’s pitch and details, and whether ventilation work is proposed or needed. If one contractor recommends changing ventilation and another does not, ask both to explain the reasoning and identify the work being priced.
Warranty information also needs a close read. Ask what warranty applies to the materials and what, if anything, covers workmanship. Confirm who provides each warranty, what conditions or maintenance requirements apply, and whether the documents will be supplied after installation. Avoid treating a long warranty period as a substitute for clear product specifications or a well-defined scope.
Comparing estimates in a simple worksheet can help. Use one column for each contractor and rows for the same scope items. Mark each item as included, excluded, provisional or unclear. That makes omissions visible without pretending that different proposals are identical.
A lower estimate may reflect a genuine difference in labour, materials, overheads or the contractor’s approach. It may also be based on a narrower scope. Check whether removal, disposal, flashings, underlay, access equipment, repairs and GST are treated consistently before deciding that the lower figure represents a saving.
Be cautious if a contractor cannot explain what the price covers, avoids specifying products, or is unwilling to put assumptions and exclusions in writing. A very low estimate can become more expensive if important work is later added, but a higher estimate is not automatically better either. Ask each roofer to justify the scope and price in plain language, then assess whether the proposal gives you a clear route from the initial inspection to completion.
The final amount may change if the roof’s condition differs from what could be seen before work began. Deteriorated decking, damaged framing, unexpected layers or details that require additional work can affect the scope. Changes requested by the homeowner, such as a different material or finish, may also alter the price.
Before signing, agree how changes will be handled. The written terms should explain how the contractor will describe the problem, provide a price or estimate for the additional work, and obtain approval. Ask whether the work can continue safely while a decision is pending, and what happens if the change affects the schedule. Keep written records of approvals and any revised totals.
For budgeting, separate the agreed project price from uncertain items. If repairs are provisional, ask the contractor what conditions would make them necessary and how they will be measured or priced. This gives you a more realistic view of the potential cost without treating an unconfirmed repair as certain.
There is no fixed number that suits every project. Getting several written estimates can help you see whether the proposed scope and pricing are broadly comparable, but only if each contractor is assessing the same work. Prioritise clarity and a credible site assessment over collecting a large number of incomplete figures.
A preliminary estimate may be based on supplied information, but it should state what has not been checked and which assumptions affect the price. A site assessment can help identify access issues, roof details and visible signs of deterioration. Ask how concealed conditions will be handled if they cannot be confirmed until removal begins.
Not necessarily. Some estimates include a defined allowance, while others exclude concealed repairs or price them only after the roof covering is removed. Ask what is included, how damage will be recorded and whether you must approve a separate price before repair work proceeds.
Usage varies, so ask the contractor what the document commits to and which parts can change. A written estimate may rely on assumptions or provisional amounts, while a quote may set out a defined price for a stated scope. In either case, read the exclusions, validity period and variation terms rather than relying on the title.
Only after confirming that the lowest proposal covers the same materials, removal, installation details, repairs, disposal and other work as the alternatives. If important items are missing or unclear, ask for a revised written estimate before comparing totals. Choose the proposal that offers a suitable, clearly documented scope and terms you understand, not simply the smallest headline figure.
A sound new roof estimate makes the proposed work, uncertain items and approval process clear. Compare like with like, ask about every gap and keep the agreed scope and any changes in writing before work begins.
