Metal and Colorbond Roofing across Macarthur

If you live anywhere between Harrington Park and Gregory Hills, you already live under a metal roof. The whole western half of the Macarthur growth corridor was built in sheet steel, and the older estates on the Campbelltown side are steadily converting to it as their tile roofs reach the end.

We install and repair Colorbond and other metal roofing across the district, new builds and conversions alike. Free inspection and a written quote on (02) 4601 5100.

Why sheet steel suits this district

Inland Macarthur punishes a roof differently to the coast. Nobody out here is fighting salt; the enemies are heat, hail and sheer summer intensity. Metal handles all three better than concrete tile:

• No mortar. The single biggest maintenance item on a local tile roof is ridge pointing cooked by inland heat. Sheet steel has no pointing at all.
• Hail dents, it does not crack. A hailstone that fractures a concrete tile and lets water through will usually only mark steel.
• Low pitch capability. Modern homes with narrow lots, parapets and big alfresco additions need roof planes that tile physically cannot drain.
• Weight. Steel is a fraction of the mass of concrete tile, which is why a tile-to-metal conversion almost never needs frame upgrading.

Picking a profile

Three families of profile cover nearly every residential job in the area.

Classic corrugated is the rounded profile most people picture. It suits traditional cottage forms, which is why it is the right answer on older houses around Camden and Elderslie where the roof needs to read as period-appropriate.

Trapezoidal ribbed profiles have taller, squarer ribs, span further between battens and drain at lower pitch. They are what most of the newer Oran Park and Mount Annan homes are clad in.

Standing-seam and concealed-fix systems hide the fixings entirely and give a very flat, modern line. More expensive, and more sensitive to installation quality.

The decision is partly aesthetic and partly arithmetic: the roof pitch and rafter span narrow the options before anyone talks about looks.

Colour and heat

New-estate Macarthur has largely gone dark — the charcoals, greys and near-blacks. If you are in a newer release at Oran Park, Gregory Hills or Harrington Park, check your estate design guidelines, because the palette is often prescribed rather than chosen.

Where you do have a choice, treat colour as the smallest part of a thermal decision. What matters more is what goes under the steel.

What goes under the sheet

A metal roof is a system, and the layers below the steel do the work that the steel cannot.

• Reflective sarking blocks radiant heat and catches any wind-driven water that gets past a lap.
• Thermal blanket adds insulation at the roof plane and dampens rain and hail noise at the same time.
• Anti-condensation measures matter inland. Clear winter nights in the Nepean and Georges River valleys drive the underside of a steel roof below the dew point, and the condensate has to be managed rather than allowed to drip into insulation.
• Roof ventilation moves the superheated air out of the roof cavity in summer, which takes real load off your ceiling and your air conditioner.

The details that decide whether it leaks

A metal roof almost never fails in the middle of a sheet. It fails at the edges and the holes.

• Apron and step flashings where a lower roof meets a wall.
• Parapet and box gutter junctions, common on the high-front facades through the newer estates and unforgiving if the fall or overflow provision is wrong.
• Penetrations — skylights, flues, vents, solar mounts, antenna feet.
• Valleys, which concentrate the water from two planes into one line.
• Ridge and barge capping laid with the right lap and fixing pattern for the profile.

If you have a leak in a metal roof, the answer is in that list. See roof repairs for how we trace it.

Fixings: the quiet ten-year problem

Screws hold the roof on and seal it at the same time, through a rubber washer under the head. Ultraviolet light and heat cycling eventually harden that washer until it no longer compresses. Then every screw on the exposed planes becomes a small open hole.

On the first wave of estate housing at Gregory Hills, Currans Hill and Harrington Park, this is now a live issue. It is inspected easily and fixed cheaply if you catch it before the ceiling tells you.

Converting a tile roof to metal

Common through the older Campbelltown estates, and genuinely worth considering when a tile roof is finished rather than merely tired. Battens are reset to the sheet manufacturer span tables, sarking and insulation go in while the frame is open, and all valleys, flashings and gutters are renewed rather than reused. The full sequence is on the roof replacement page.

Cost

Metal roofing is priced on area, pitch, profile, the number of hips, valleys and penetrations, and access. A single-plane skillion in Narellan and a six-valley two-storey at Mount Annan are not the same job even at the same square metreage.

We quote in writing after an inspection, with the material, colour, insulation and flashing work itemised. Call (02) 4601 5100 or send the details through the quote form.