Start with the right question
Most people ask 'what will it cost?' first. That matters, but it is the wrong place to start. A cheap repair on a roof that is wearing out everywhere is money spent twice. An expensive replacement on a roof that only needed one valley fixed is money wasted.
Work through the questions below with your roofer's inspection findings in hand. If most of your answers lean one way, the decision is usually clear.
Question 1: How widespread is the damage?
This is the biggest single factor.
- Isolated: one or two leaks, a handful of cracked tiles, a single rusted valley iron, one section of loose ridge capping. This is repair territory.
- Patchy: problems on several roof planes, but the bulk of the roof is sound. Often a restoration or a series of targeted repairs.
- General: porous or brittle tiles throughout, rust across many sheets, sarking that has failed everywhere. This usually points to replacement.
Ask your roofer to mark up a photo or sketch of where the problems are. Seeing them on a plan makes the pattern obvious.
Question 2: What is underneath?
Tiles and sheets get the attention, but the layers below decide whether a roof can be saved.
| Layer | Repairable? | When it pushes towards replacement |
|---|---|---|
| Battens | Individual battens can be replaced | Widespread splitting, rot or corroded fixings |
| Sarking | Small tears can be patched from below | Missing, brittle or sagging across the roof |
| Roof frame | Localised damage can be repaired | Sagging ridgelines or structural movement (needs proper assessment) |
| Flashings and valleys | Usually replaceable on their own | Rarely the deciding factor alone |
If the battens or sarking need replacing across most of the roof, the tiles or sheets have to come off anyway. At that point a full re-roof often makes more sense than putting old material back.
Question 3: What is the roof made of?
Concrete tile
The most common roof on Perth's 1960s to 1990s double-brick homes. Individual tiles and ridge capping are easy to repair. Once the surface has eroded and tiles are porous, though, repairs stop solving the problem.
Terracotta
Long lived but brittle with age. If tiles crack every time someone walks on them, each repair risks causing more damage.
Steel
COLORBOND and Zincalume roofs can be repaired sheet by sheet, and fixings or flashings replaced. Rust through the sheets, especially in coastal suburbs, tends to spread.
Asbestos cement
This one is different. You should not repair, cut, drill or water-blast asbestos cement roofing. WorkSafe WA requires a licensed asbestos removalist to remove more than 10 square metres of non-friable asbestos. Replacement is usually the only sensible long-term path. See our asbestos roof replacement page.
Question 4: How often has it needed fixing?
Keep a rough log of call-outs. One repair in ten years is a healthy roof with an isolated fault. A new leak every winter, each in a different spot, tells you the roof is failing as a whole. Our guide to roof leaks and water damage covers how to tell recurring leaks from one-off problems.
Question 5: How long will you stay?
Your plans change the maths.
- Staying long term: a full replacement resets the clock and gives you a chance to upgrade sarking, insulation and ventilation at the same time.
- Selling within a few years: sensible repairs and a clean inspection report may be enough. Buyers' inspectors will still note a worn roof, so be realistic.
- Renovating soon: if an extension or second storey is on the cards, coordinate the roof work with it rather than doing it twice.
Question 6: Do you want to change anything?
A replacement is the only time you can easily change material, colour or roof form. Common reasons Perth owners choose replacement over repair include:
- switching heavy concrete tiles for lighter COLORBOND steel
- choosing a lighter, more reflective colour for summer heat
- adding a roof blanket or new sarking
- improving roof-space ventilation with whirlybirds or ridge vents
- fixing drainage problems such as undersized gutters or box gutters
Weigh appearance, weight, noise and upkeep before choosing a new material.
Repairs that only buy time
Some fixes are perfectly honest but temporary, and it helps to know which ones. Silicone smeared over a cracked tile or a lifted flashing might stop a drip for a season, then fail in the next summer's heat. Coating a badly eroded concrete tile roof can improve its looks without restoring the strength of the tiles underneath. Patching rust holes in steel sheets slows the problem but rarely stops it once corrosion has taken hold across a roof plane.
None of these is wrong if you understand what you are buying. They can be sensible while you save for a re-roof or plan a renovation. Just ask your roofer directly how long a repair is likely to hold and what would make it fail, and write the answer down.
What your inspection report should tell you
Whichever direction you lean, base the decision on a written report rather than a conversation on the driveway. A useful report includes:
- photos of each problem, labelled with where on the roof it is
- the condition of tiles or sheets, battens, sarking, flashings, valleys and gutters
- what was checked from inside the roof space, if access allowed
- a repair option and a replacement option where both are realistic
- anything that needs a specialist, such as suspected asbestos
Our guide to what happens during a roof inspection explains the process.
Putting it together
| Situation | Usual direction |
|---|---|
| Few isolated faults, sound tiles or sheets | Repair |
| Ridges and pointing tired, tiles still sound | Restoration |
| Widespread wear, recurring leaks | Replacement |
| Failed battens or sarking across the roof | Replacement |
| Asbestos cement roofing | Replacement by licensed removalist and roofer |
| Wanting a different material or colour | Replacement |
If you are leaning towards repair, our roof repairs page explains what is typically involved. If replacement looks likely, the re-roofing page walks through the job from strip-off to final clean-up.
A word on cost
We don't publish prices because every roof is different: size, pitch, access, material, how much of the structure needs work and whether asbestos is involved all change the number. What we can say is that comparing a single repair invoice against a full replacement quote is not a fair comparison. Add up likely repairs over the next several years and compare that instead. The roof replacement cost guide explains what drives the price.
Checking the contractor
Whichever way you go, we ask the contractors we work with to hold the registrations and insurance the job needs. Ask to see them before work starts. In WA, residential building work over $20,000 generally needs a registered building contractor, so check with Building and Energy if you are unsure. Consumer Protection WA explains what your contract should include for larger residential jobs.
Get any recommendation in writing, with photos. A clear report makes it easy to compare quotes and to come back later if something changes.
Get an honest assessment
The quickest way to settle repair versus replace is to have someone look at the roof properly. Request a free on-site quote through our contact page and a local contractor will inspect the roof, show you what they find and price the options side by side.