Over time, your roof builds up a lot of dirt, moss, and lichen, and the harsh Aussie sun can also take its toll. Cleaning your roof tiles is a vital step to ensure your property keeps looking good and to protect your investment. At Pressure Up House Washing, we’re all about bringing homes back to life, and we believe that starts at the top. Whether your roof tiles are concrete or terracotta, here’s everything you need to know to clean roof tiles safely, properly, and effectively.
Why Clean Roof Tiles?
Regular roof tile cleaning keeps your home looking great and helps prevent long-term damage. Here’s why it’s worth the effort:
- Stops moss, mould, and lichen growth – Left untreated, they trap moisture and can degrade your tiles.
- Prevents staining and discolouration – Especially in shaded or damp areas.
- Extends roof life – Less wear and tear, fewer cracked or broken tiles.
- Improves curb appeal – A clean roof can completely lift the look of your home.
- Prepares for painting – If you’re planning to repaint or reseal, clean tiles are a must.
Safety First: Prepping for a Roof Clean
Before you touch a pressure washer, prep properly for a safe and efficient clean.
Use the Right Safety Gear
- Non-slip shoes
- Safety harness if the roof is steep or multi-level
- Safety glasses and gloves
- Long extension cords secured safely
Secure Your Setup
- Use a stable ladder—never lean it against the gutter
- Install roof guard rails if possible
- Disconnect rainwater tanks so chemicals don’t contaminate your supply
- Move outdoor furniture and cover plants below with tarps
At Pressure Up, our crew uses harnesses and safety systems every time we clean a roof—and our free drone inspections mean we can assess from above before stepping foot on it.
Types of Roof Tiles and What They Need
Terracotta Roof Tiles
Terracotta tiles are made from natural clay and fired at high temperatures to create their signature rich colour and durability. They’re known for their rustic aesthetic and excellent performance in hot climates—perfect for Toowoomba homes.
Cleaning Tip: Terracotta tiles are more porous and prone to moss and algae. We recommend low to medium-pressure cleaning paired with eco-friendly treatments to avoid cracking the tiles or damaging their glazed surface.
Pros:
- Naturally insulating and energy-efficient
- Long lifespan (50–100 years)
- Weather and fire resistant
- Classic appearance
Watch out for: Their brittleness. While durable in the right hands, these tiles can crack easily under pressure or weight—especially during DIY cleans.
Clay Roof Tiles
Clay tiles are similar to terracotta but can come in more styles, finishes, and colour variations. They’re known for being long-lasting, fireproof, and weather-resistant. In fact, some clay tiles can last up to 150 years.
Cleaning Tip: Like terracotta, clay tiles are best cleaned with a gentle soft wash method and mould inhibitor. Avoid harsh chemicals—these can affect the finish and weaken the tiles over time.
Pros:
- Excellent water resistance
Eco-friendly and fully recyclable - Help regulate home temperature
- Come in various finishes and styles
Watch out for: They’re one of the more premium options—both in terms of cost and installation complexity.
Slate Roof Tiles
Natural slate is a high-end roofing material with a unique, timeless look. It’s made from natural stone, which means each tile has its own texture and colour. It’s extremely durable, lasting 75 to over 200 years with proper care.
Cleaning Tip: Soft washing is a must. Slate is heavy and can be fragile under pressure. A low-pressure system and gentle roof detergent will clean without compromising the slate or any underlayments.
Pros:
- Superior lifespan
- Distinctive and elegant appearance
- Fire, wind, and moisture resistant
Watch out for: Very heavy—your roof needs to be structurally reinforced. Also, they come with a premium price tag, both for the materials and professional installation.
Solar Roof Tiles
Solar tiles combine roofing and energy generation in one sleek solution. They look like standard tiles but are made with tempered glass and solar cells that convert sunlight into electricity.
Cleaning Tip: Never pressure wash solar tiles. Use soft water, a mild detergent, and a non-abrasive cloth or soft brush. For hard-to-reach areas, we recommend using specialised solar cleaning tools—or better yet, call the pros.
Pros:
- Eco-friendly energy generation
- Visually integrated (no bulky panels)
- Long-term energy savings
Watch out for: High upfront cost. Also, not all roof pitches or orientations are suitable, so a professional inspection is essential before installation or cleaning.
Metal Roof Tiles
Metal tiles—often made from steel, aluminium, or zinc—combine the look of traditional tiles with the durability of metal sheeting. They’re popular for their lightweight build and high fire and wind resistance.
Cleaning Tip: Use low-pressure water and a gentle detergent. Avoid aggressive scrubbing, which can damage protective coatings and lead to rust or corrosion over time.
Pros:
- Lightweight and easy to install
- Long-lasting (up to 50 years)
- Reflective surface = cooler home
- Often made from recycled materials
Watch out for: Can be noisy during rain or hail. Also, ensure regular maintenance to prevent rust or coating wear.
Cleaning Methods: What Actually Works?
1. Pressure Washing
Pressure washing is a fast and effective method to blast away grime, mould, and dirt—when done right.
How to Do It:
- Use a machine with a PSI around 1500–2000
- Hold the nozzle ~30cm from the tile surface
- Start from the top down to avoid washing dirt over clean areas
- Keep a steady pace to avoid striping or damaging tiles
✅ Best for: Thick dirt, moss, lichen
⚠️ Caution: Can break brittle tiles if pressure is too high or used at the wrong angle
At Pressure Up, we adjust pressure levels and use surface-specific nozzles to clean without causing damage.
2. Soft Washing
For older roofs or tiles showing signs of wear, soft washing is the gentler, safer method.
What You’ll Need:
- A low-pressure sprayer
- Eco-friendly roof cleaner (biodegradable, non-toxic)
- Water source
Steps:
- Spray cleaner evenly from top to bottom
- Let it sit for 10–15 minutes
- Gently rinse using low pressure
✅ Best for: Delicate terracotta tiles or older roofs
✅ Bonus: Eco-friendly options won’t harm your garden or pets
3. Chemical Treatment (Anti-Moss or Algae Wash)
Some roofs need that extra kick to kill off deep-rooted growth like lichen.
Products to consider:
- Sodium percarbonate-based cleaners
- TSP (trisodium phosphate) for tough stains
- 50/50 bleach and water mix (with care)
How to Apply:
- Apply in dry weather so it has time to activate
- Spray across the roof, wait, then rinse thoroughly
Don’t let any chemical dry on your tiles
⚠️ Bleach-based products can corrode tiles if not rinsed off thoroughly. Avoid high-chlorine formulas.
Step-by-Step Cleaning Guide
- Inspect the Roof
- Look for cracked or missing tiles
- Remove loose debris by hand or with a blower
- Apply Anti-Moss Spray (Optional)
- Let it sit before rinsing
- Wash the Tiles
- Use pressure or soft wash depending on roof type
- Always rinse from bottom up to control runoff
- Final Rinse
- Remove all chemical residues thoroughly
- Clean Gutters
- Roof debris usually ends up in gutters—flush them out before you finish
- Apply a Sealant (Optional)
- After drying, sealing your roof helps prevent regrowth and staining
Aftercare: Keep That Roof Looking Fresh
- Annual Inspections – We recommend a yearly inspection to check for cracks, mould, and water damage.
- Seasonal Touch-Ups – Especially after storms or heavy tree shedding.
- Reapply Sealant – Every 3–5 years for long-term tile protection.
At Pressure Up, we provide a variety of house washing services, including roof cleaning.
Should You DIY or Call the Pros?
DIY can save money—but only if you’ve got the tools, the time, and the confidence to get up on a roof safely.
Hire the Pros If:
- Your roof is steep, multi-level, or fragile
- You’re unsure about safe chemical use
- You’d rather not risk injury or damage
- You want it done properly!
With our advanced equipment, experienced team, and local Toowoomba know-how, Pressure Up House Washing gets the job done right—every time.
FAQs
How often should I clean my roof tiles?
For terracotta tiles, once a year. Concrete can go 2–3 years between cleans unless you’re in a high-moss or tree-covered area.
Can pressure washing damage my roof?
Yes—if done with the wrong pressure or nozzle. Always use a medium setting and work at a safe distance.
Do I need to apply chemicals?
Not always, but they help prevent regrowth. Eco-friendly options are safer for your roof and the environment.
Is it safe to walk on tiled roofs?
Only with proper footwear and safety gear. Always walk where tiles overlap and avoid brittle areas.
Do you offer free roof inspections?
Yes! We use drones to safely inspect every inch of your roof—no obligation.
Ready to Refresh Your Roof?
Don’t let dirt and moss drag down the look (and lifespan) of your home. Whether you want a one-off clean or regular roof care, Pressure Up is Toowoomba’s trusted team for professional, safe, and sparkling results.
