Restoring a Terracotta Tile Roof: What's Different
Terracotta behaves nothing like concrete tile and treating it the same way is a common, costly mistake. Here's what's different about restoring a terracotta roof and why the approach changes.
Fully licensed & accredited — Builders Registration BC105819 · Painters Registration PC102072 · Patent ID AU-A-2020100623
Terracotta is not concrete tile with a nicer colour. It behaves differently, it fails differently and a restoration approach designed for concrete will damage it.
The first thing worth saying is that a terracotta roof usually should not be coated at all.
Why coating terracotta is usually wrong
Terracotta is fired clay, frequently glazed and its colour is the material rather than a surface treatment. It does not fade the way concrete does because there is nothing to wear off.
Applying a coloured membrane over it permanently alters the appearance of a building and removing that membrane later is difficult and expensive.
On a character home, that change is visible from the street and generally regrettable. On a heritage listed property it may not be permitted at all.
What terracotta actually needs
Cleaning, carefully, to remove organic growth and accumulated grime while respecting a brittle century old material.
Tile Roof Repairs Perth replaced with matched salvage stock.
Roof Bedding & Pointing Perth renewed, which is where most terracotta roof problems actually live.
Roof Valley Repairs Perth and flashings attended to.
Where porosity is genuinely a problem on unglazed tiles, a penetrating sealer that reduces water absorption without altering appearance is a different product to a coloured membrane and can be appropriate.
Handling brittle tiles
Old terracotta does not tolerate foot traffic the way modern concrete does. It is harder, more brittle and less forgiving.
On steep pitches, common on the era of housing that carries terracotta, the roof frequently has to be worked from above using boards and access equipment rather than walked casually.
A careless operator can break five tiles replacing one and on a discontinued profile that is a genuine problem rather than an inconvenience.
Cleaning method matters more than usual
High pressure cleaning suitable for concrete can damage aged terracotta and drive water under laps.
Treating organic growth chemically and allowing it to die, followed by controlled lower pressure washing, is the appropriate approach.
Glazed terracotta cleans up remarkably well. Unglazed is more porous and holds staining more stubbornly.
Matching and salvage
Early twentieth century profiles have not been manufactured for generations. Matching depends on reclaimed stock from specialist yards.
Sourcing takes longer than for concrete and occasionally requires patience across weeks rather than days.
Where a match genuinely cannot be found, taking tiles from a rear or hidden elevation and placing the substitutes there is far better than a visible patch on the street facade.
The mortar question on old roofs
Original bedding on very old roofs may be lime based rather than modern cement and it behaves differently. It is softer, more permeable and more forgiving of movement.
Replacing it with hard modern cement can trap moisture and stress the tiles, which is the same mistake that has damaged limestone walls across Fremantle for decades.
Sympathetic repair means matching the behaviour of the original material rather than simply using whatever is strongest.
Heritage controls
Listed properties and homes within heritage precincts frequently carry restrictions on visible changes, including roof material, profile and colour.
Establish this before any work is specified. It is far easier to plan around than to unwind.
Local government heritage officers are generally helpful and it costs nothing to ask.
What a good terracotta job looks like when finished
It looks like the same roof, cleaned and repaired, rather than a different roof.
The ridge line is straight, the pointing is neat and appropriate and any replacement tiles are difficult to pick out.
Nobody driving past should be able to tell that work was done, which is precisely the opposite of the goal on a concrete tile restoration.
We restore terracotta roofs throughout Perth including Mount Lawley, Menora, Inglewood, Maylands and Highgate. Ring 0421 768 842.
Why terracotta roofs outlive their owners
Fired clay is chemically stable in a way few building materials are. It does not fade, does not chalk and does not degrade under ultraviolet exposure.
What ages around it is everything else. Mortar, valleys, flashings, fixings and battens all have shorter lives than the tiles they support.
A century old terracotta roof needing work almost always needs work to those components rather than to the tiles themselves.
Common faults specific to terracotta
Tile Roof Repairs Perth where old fixings have corroded or timber battens have degraded.
Cracked or missing capping, frequently in decorative profiles that are difficult to source.
Previous repairs using inappropriate modern materials, particularly hard cement mortar and roof cement patches.
Moss and lichen on shaded elevations, which on unglazed tile can be more tenacious than on concrete.
When replacement genuinely is the answer
Widespread batten degradation, which is a Roof Tiling Perth and relay rather than a Roof Replacement Perth. The tiles go back down.
Extensive tile loss where insufficient salvage stock exists to make good.
Structural problems in the roof framing itself.
In every one of those cases the tiles are usually worth keeping and any proposal to discard sound terracotta deserves hard questions.
Finding somebody who has done it before
Ask specifically about terracotta experience rather than roofing experience generally. The techniques differ and the consequences of getting it wrong are permanent.
Ask how they source matching tiles and which yards they use.
Ask what pointing compound they propose and whether they have worked on lime bedded roofs.
We restore terracotta across Perth including Guildford, Bassendean, South Perth, Victoria Park and Como. Ring 0421 768 842.
Glazed versus unglazed, and why it changes everything
Glazed terracotta carries a vitrified surface applied before firing. It sheds water, resists staining and cleans up remarkably well even after decades of neglect.
Unglazed terracotta is porous. It absorbs moisture, holds organic growth more stubbornly and darkens with age in a way glazed tile does not.
That distinction determines whether a penetrating sealer is worth considering, how aggressively the roof can be cleaned and what result is realistically achievable.
Establish which you have before agreeing to any process. A contractor who cannot tell you is not the right contractor for a heritage roof.
We restore terracotta across Perth including Nedlands, Dalkeith, Shenton Park, Subiaco and Wembley. Ring 0421 768 842.Roof Bedding & Pointing Perth deserves separate mention. Traditional terracotta capping came in decorative patterns, sometimes with finials at the apex and those elements define the silhouette of a period house against the sky.
Losing them to a modern substitute during otherwise competent repair work is a small tragedy repeated across Perth suburbs weekly. Salvage yards stock reclaimed capping precisely because owners eventually want it back.
Photograph yours before any work commences. Insist matching capping is sourced rather than approximated and keep any removed pieces even if they appear beyond repair. Somebody else may need them.
Weather exposure differs across a single terracotta roof more than owners realise. Northern elevations bleach gently over decades while southern faces accumulate moss and eastern slopes catch morning dew that western slopes never see.
Consequently one roof frequently needs four slightly different approaches and a contractor treating every elevation identically will over clean some areas while under treating others.
Dulux AcraTex accredited applicators
Powerdrive Roofing is an accredited applicator for the Dulux AcraTex roof restoration system, so your coating carries the manufacturer’s product warranty alongside our own 10-year workmanship warranty. How the Dulux AcraTex warranty works →
What Perth homeowners say
There are 206 reviews on our Google listing. Photographs of finished work sit alongside them, which is more useful than anything we could write here.
Materials, warranties and matching
Materials matter more than most quotes admit. We match discontinued tile profiles through salvage stock at Roof Top Industries rather than putting a modern profile across an older elevation, and current ranges come from Bristile Roofing, Perth founded in 1929, or Monier. Coatings are the Dulux AcraTex roof restoration system, applied under accreditation so the manufacturer warranty stands.
Need your roof sorted? Let's talk.
Tell us about your roof and the problem, we'll tell you the likely cause and what it'll take to fix.