Re-roofing a mountains home: what gets replaced, and why

When replacement is the honest answer

A re-roof is the right call in three situations. The battens, sarking or valley boards underneath have failed, so there is nothing sound to fix to. The roof has been patched repeatedly in the same places and the patches have stopped holding. Or the covering itself has reached the end of its service life — crazed and porous terracotta, concrete tiles that are shedding their surface in sheets, or old corrugated steel that has corroded through at the laps and fixings.

What a re-roof is not is the answer to a roof that merely looks bad. Moss on a southern pitch, a faded coating and crumbled ridge pointing all look alarming and are usually a roof restoration job at a fraction of the cost. We would rather send you down that road if that is what the roof needs.

Call (02) 4703 5000 for a look and a written quote. Nothing to pay for either.

What a re-roof actually includes

The covering is the visible part and the smallest part of the decision. Stripping back to the frame is what makes the job worth doing, because it is the only time anyone gets to see and fix the layers underneath:

• Battens. Replaced where they are soft, split, sagging or showing nail pull-through.
• Sarking. A full sarking layer under the covering, which matters twice over here: it is a second line of defence against wind-driven rain and it is a requirement on bushfire-prone land where a Bushfire Attack Level applies under AS 3959.
• Insulation. Worth getting right while the roof is open. Winter minimums at Blackheath sit between roughly minus three and five degrees.
• Valleys, flashings and cappings. New valley irons, new flashings at chimneys, walls, skylights and penetrations, new ridge and hip detail.
• Roof-to-wall junctions and openings. Sealed, with non-combustible ember guards where the bushfire assessment calls for them.
• Gutters and downpipes. Often replaced at the same time because they are easier to reach with the roof off.

Tile or steel, at altitude

Both work here. The deciding factors are usually the house, the block and the planning constraints rather than any general rule.

Concrete or terracotta tile suits the mid-century and later brick-veneer stock through Blaxland, Springwood and Winmalee, and it is the like-for-like option on a tiled heritage roof. The trade-off is that every tiled roof up here has bedded ridge caps, and bedded mortar is exactly what freeze-thaw cycling attacks. Plan on repointing being part of the maintenance cycle.

Colorbond steel has real advantages on a steep mountain pitch: lighter on the frame, no ridge mortar to break down, it sheds leaf litter and snow faster, and it is non-combustible, which simplifies the bushfire detailing. Short-run corrugated reads correctly on a weatherboard cottage or a Federation roofline. Our metal and Colorbond roofing page goes further into profiles and fixings.

The one thing a steel roof needs that a tile roof does not is proper condensation control. A cold steel roof over a warm, humid interior will sweat on the underside on a frosty night, so sarking with an anti-condensation layer and real ceiling-space ventilation are part of the specification, not an extra.

Two sets of constraints, often on the same house

Heritage. Katoomba, Leura and Mount Victoria carry conservation areas — Katoomba South, Crown Village, Grimley Estate, Norths Estate, Leura North and Leura South among them — plus individual heritage items such as the 1849 Toll House and the surviving Federation guesthouse stock. Material, profile and colour are all in scope.

Bushfire. With roughly 70% of the local government area inside Blue Mountains National Park, most blocks here sit on mapped bush fire prone land. Where a BAL applies, AS 3959 drives the roof detail: full sarking, sealed roof-wall junctions, non-combustible ember guards at openings, metal or uPVC gutters, box gutters non-combustible and fully flashed. Your Section 10.7 certificate and a BAL assessment are what confirm the level for your property.

Where the two overlap — a heritage cottage on a bush-interface block at Medlow Bath, say — the specification has to satisfy both. That is a conversation to have before the quote, not after.

Access, scaffold and the winter window

Mountains blocks are frequently steep, narrow and tightly treed, with long driveways and little room to stand a crane or stack materials. On some sites getting sheeting to the roof is a bigger planning question than the roof itself. We work that out on the inspection and put it in the quote rather than discovering it on day one.

Above 900 metres the practical working window narrows through winter: short days, fog that keeps surfaces wet, and frost. We would rather schedule a re-roof into a settled stretch than start one in the wrong month.

The sequence

1. Free inspection, measure, discussion of material and colour, written quote.
2. Any approval needed is identified up front.
3. Materials ordered; scaffold and edge protection set up.
4. Strip and dry-in in sections, so no part of the roof is open longer than it has to be.
5. Battens, sarking, insulation, flashings, valleys.
6. Covering laid, ridges and penetrations detailed, gutters and downpipes connected.
7. Site cleared, gutters flushed, workmanship warranty issued in writing.

What drives the cost

Roof area and pitch first. Then material and profile. Then access — scaffold, how far materials have to be carried, whether there is any hardstand at all. Then what we find underneath once the covering is off, which is why the quote itemises allowances rather than hiding them. Approval requirements in a conservation area and any BAL-driven detailing also show up in the number.

We do not quote a price per square metre over the phone. Someone has to see the roof first.

Talk it through

Call (02) 4703 5000 or use the quote form. If you are weighing replacement against restoration and want an independent write-up before you spend, start with a roof inspection and report. Work is carried out by established, licensed and insured roofing contractors working to NSW Fair Trading requirements, with a written workmanship warranty on completion.