Slate Roofing near you

Work out three things in this order: whether the building is listed at state level, whether it is a local heritage place, and whether it falls inside a character or conservation overlay. Those are different instruments with different consent authorities, and a building can be caught by more than one. The consent authority, not the contractor, decides which of them applies to your address.

The New South Wales standard exemptions are a useful model for how these schemes think, because they turn on the significance of the fabric rather than on the size of the job. Maintenance as part of the continuous protective care of a place is exempt. Repair or replacement of damaged or deteriorated non-significant fabric that is beyond further maintenance is exempt, and the published examples include replacing decayed or destroyed roof gutters with new gutters. Replacement of significant fabric is allowed only where a part of the item has decayed beyond further maintenance, and any new fabric must be sympathetic to the appearance, composition, detailing, size, position and finish of the existing.

One condition inside those exemptions is the one that most often trips up roof work: new materials or processes must not exacerbate the decay of significant fabric through chemical incompatibility. On a slate roof that is not an abstraction. Lead, copper, zinc and coated steel all end up touching each other at flashings, valleys and gutters, and the wrong combination eats one of them.

Slate outlives its fixings. The commonest reason an Australian slate roof leaks is not that the slate has failed but that the nails have corroded, the battens have moved or someone has walked on it. That is why a competent assessment starts underneath, in the roof space, looking at the boarding, the battens and the daylight, rather than from a ladder at the gutter line.

Because the fabric is significant, the default answer in a heritage context is repair rather than replacement, and the exemptions are built around that assumption. A roof where a proportion of slates have slipped and the rest are sound is a repair. A roof where the fixings have failed generally, or where the boarding is soft, may need stripping and re-laying with the original slate reinstated, which is a different consent conversation from simply replacing the covering.

Beware of the middle option that gets offered a lot: coating, sealing or spraying a slate roof. It changes the appearance and the breathability of significant fabric, it is extremely difficult to reverse, and on a listed or overlaid building it is exactly the kind of process that can fall foul of the condition about not exacerbating decay through incompatibility. Ask the consent authority before, not after.

Expect a documented condition survey first: which slates are cracked, slipped or missing, what the fixings look like, what state the battens and boarding are in, and what previous repairs have been done and with what. On an older roof, the previous repairs are usually the most informative part of the survey.

Access and protection come next, and on a heritage building they cover more than the workers. Scaffolding has to be designed so it does not load or mark significant fabric, salvaged slate has to be stacked and sorted rather than tipped, and the interior has to be protected because an open slate roof is genuinely open. Set out in advance how much of the roof will be uncovered at any one time and what happens if rain arrives.

Then the work itself: slates sorted by size and thickness, the sound ones set aside for reuse on visible elevations, new or salvaged material matched to what is there, the fixings renewed, and the flashings and valleys reformed in compatible metal rather than sealed. Finish with a photographic record of what was found, what was reused and what was replaced. On a heritage building that record is part of the asset.

Heritage consent and trade licensing are separate systems and you need both answers. On licensing, New South Wales treats roof plumbing as its own class covering guttering, downpipes, roof flashing and roof coverings, with a contractor licence required for residential work above the Home Building Act threshold. Queensland's QBCC roof tiling class covers cutting and fixing roof tiles and shingles to roof and fascia structures, along with battens, sarking, bedding, pointing and associated flashing, and a QBCC licence is required for building work above the state threshold and for plumbing and drainage at any value.

On consent, ask the authority three specific questions before you sign anything: does this work fall within a standard exemption, if not what application is required, and what evidence will be wanted about matching materials. Getting a written answer costs nothing and is the only thing that protects you if a neighbour or an inspector takes an interest halfway through.

Finally, ask the contractor for slate references you can actually look at, in your city, on buildings of a similar period. Slating is a skill that is thinly spread in Australia, and the gap between someone who has re-laid slate roofs and someone who has replaced slates with something else is very wide.