Roof Restoration Procedures & Technical Information
A proper roof restoration requires following the best techniques while understanding why improper methods fail. Below is a step-by-step breakdown of the process, along with common mistakes and why each step is crucial.
Step 1: Replacing Damaged or Broken Tiles
Why is this important?
Tiles serve as the first line of defense against weather conditions. Any cracks, chips, or damage can compromise the roof’s ability to keep water out. Even minor damage can escalate, leading to leaks, insulation failure, and structural deterioration.
Common Mistakes:
- Ignoring minor cracks – Small cracks can expand over time due to thermal expansion, allowing moisture to seep in.
- Not replacing broken tiles – A single broken tile can lead to a domino effect, causing neighboring tiles to shift and further deteriorate.
- Improper tile placement – Incorrectly placed tiles can disrupt the interlocking system, leading to weak spots in the roof.
Best Practices:
✔ Inspect the entire roof to identify damaged tiles.
✔ Replace any tile with a chip larger than 50mm to prevent leaks.
✔ For smaller chipped tiles, relocate them to a less visible part of the roof (blind side) to maintain aesthetics.
✔ Ensure the replacement tiles are properly aligned with the original roofing pattern to maintain structural integrity.
Step 2: High-Pressure Cleaning (4000+ PSI)
Why is this important?
Over time, dirt, moss, algae, and pollutants accumulate on roof tiles. These contaminants can weaken tile coatings, trap moisture, and cause premature deterioration.
Common Mistakes:
- Low-pressure cleaning – Ineffective at removing deep-seated dirt, leaving contaminants that interfere with coatings.
- Skipping cleaning altogether – Applying coatings over dirty tiles leads to poor adhesion and premature peeling.
- Excessive pressure – Using too much pressure (above 4300 PSI) can crack weaker or aged tiles.
Best Practices:
✔ Use a commercial-grade high-pressure cleaner set between 4500-5000 PSI for optimal dirt and pollutant removal.
✔ Ensure uniform pressure across the roof to prevent weak spots from breaking.
✔ Check for loose or weakened tiles that may break under pressure.
✔ Allow sufficient drying time after cleaning before proceeding to the next steps.
Step 3: Replacing Rusted Valley Irons (Colorbond Steel)
Why is this important?
Valley irons are critical for directing water off the roof and into the gutters. Rusted valley irons weaken over time, causing leaks and structural degradation.
Common Mistakes:
- Applying coatings over rusted valley irons – This only masks the problem temporarily; the rust will continue spreading.
- Using inferior replacement materials – Non-galvanized or low-quality metals corrode quickly in harsh weather.
- Improper installation – A poorly installed valley iron can lead to water pooling and leaks.
Best Practices:
✔ Completely remove rusted valley irons before applying new ones.
✔ Use Colorbond steel or a high-quality galvanized alternative for longevity.
✔ Apply a protective anti-rust primer to prevent corrosion.
✔ Ensure the valley iron is correctly positioned for optimal water drainage.
Step 4: Full Re-Bedding of Ridge Caps and Valley Tiles
Why is this important?
Bedding is the cement-based foundation that holds ridge caps and valley tiles in place. Over time, it deteriorates due to weather exposure, leading to instability.
Common Mistakes:
- Using weak sand/cement mixtures – A mix that is too sandy lacks durability, while a mix with excessive cement becomes brittle.
- Skipping complete re-bedding – Applying new mortar over old, crumbling mortar leads to premature failure.
- Not allowing proper curing time – Bedding that dries too quickly can develop cracks.
Best Practices:
✔ Use a proper mortar mix: 3 parts sand, 1 part cement for ideal strength and flexibility.
✔ Remove all old bedding before applying new mortar.
✔ Ensure uniform thickness for strong adhesion.
✔ Allow proper curing time before applying flexible pointing.
Step 5: Re-Pointing with Flexible Acrylic Compound
Why is this important?
Re-pointing is essential to seal ridge caps and valley tiles. A flexible compound allows for minor movement without cracking.
Common Mistakes:
- Over-pointing without removing old mortar – This can cause adhesion issues.
- Using inflexible compounds – Traditional cement-based pointing is prone to cracking.
- Skipping the step – Leads to leaks and weak ridge caps.
Best Practices:
✔ Use a high-quality flexible acrylic compound for re-pointing.
✔ Apply an even layer to ensure a watertight seal.
✔ Allow for natural expansion and contraction without cracking.
Step 6: Application of Nano Co-Polymer Primer
Why is this important?
Priming the roof tiles ensures proper adhesion of subsequent coatings and prevents peeling.
Common Mistakes:
- Using thick, air-trapping primers – Can cause bubbles and peeling when the tiles heat up.
- Skipping primer application – Leads to poor top coat adhesion.
Best Practices:
✔ Select the right primer:
- Nano primers for newer, fine-grained tiles.
- Thicker primers for coarse or aged tiles.
✔ Apply a uniform coat to penetrate tile surfaces effectively.
✔ Ensure complete drying before applying sealers.
Step 7: Application of High-Solids Sealer
Why is this important?
A high-solids sealer prevents calcium salt leaching and ensures even coverage of top coats.
Common Mistakes:
- Using low-quality or diluted sealers – Leads to patchy finishes and reduced longevity.
- Skipping the sealing step – Results in top coats breaking down faster.
Best Practices:
✔ Use a sealer with salt-restrictive polymers to prevent calcium leaching.
✔ Apply evenly across the roof for consistent coverage.
✔ Ensure proper drying time before applying top coats.
Step 8: Application of Two Coats of Cross-Linked Emulsion (Top Coat)
Why is this important?
The final coats protect the roof from UV radiation, pollution, and weathering.
Common Mistakes:
- Using low-quality paints – Cheaper paints contain fillers that deteriorate quickly.
- Applying a single coat – Reduces longevity and effectiveness.
- Inadequate UV protection – Leads to premature fading and cracking.
Best Practices:
✔ Use pure acrylic resin-based top coats with at least 55% solids.
✔ Apply two thick coats for maximum durability.
✔ Ensure proper curing between coats for a strong bond.
Final Step: Cleaning the Job Site
A professional roofing company ensures the entire work area is cleaned of all debris, old tiles, and cement residue.
Roof Restoration Cost Breakdown
The cost of roof restoration depends on:
- Size of the roof
- Extent of repairs needed
- Quality of materials used
- Complexity of the job
For a standard 15-square home, restoration costs typically range from $4,000 to $8,000, depending on the level of work required.
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📍 89 High St, Kew, Melbourne, VIC
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