Practical Roofing Advice for Homeowners
⚠️ IMPORTANT SAFETY DISCLAIMER
Roofing work is high-risk. Falls from heights remain one of the leading causes of serious injury and death in Australia.
The information below is provided by JSIU Roofing Pty Ltd for educational purposes only to help homeowners understand common roof issues.
🚫 We do not recommend untrained individuals access their roof.
If you choose to attempt any of the actions described, you do so entirely at your own risk.
Minimum safety requirements:
- Always use a certified safety harness
- Never work alone
- Never access a wet or slippery roof
1️⃣ How do I replace a broken roof tile without removing a whole row?
The “Kick-Up Tile Replacement” Method
You don’t need to strip an entire roof to replace one broken concrete tile.
Steps:
- Slide the tile above the damaged tile up approximately 40–50mm to disengage the locking nibs
- Lift the left edge of the broken tile over the adjacent tile lip
- Carefully wiggle the damaged tile free
- Slide the replacement tile into position
- Ensure the rear lugs hook securely onto the timber batten
- Pull the top tile back down to lock everything in place
✅ Common method used by professional roofers for isolated tile damage.
2️⃣ Can I use silicone to stop a leaking concrete roof tile?
Yes — but only as a temporary emergency repair
If a replacement tile isn’t immediately available:
Preparation is critical:
- Clean the crack thoroughly using a wire brush
- Remove moss, dirt, and dust — silicone will not bond to contaminants
Application:
- Use a neutral-cure, UV-rated roof silicone (e.g. Sikaflex, Fuller)
- Push silicone into the crack and smooth over the surface
⚠️ Limitation:
This is not a permanent solution. UV exposure will eventually cause silicone to degrade.
3️⃣ Why does my roof only leak during heavy rain or strong wind?
Common hidden causes of intermittent leaks
Check valley irons:
- Leaves and debris can block valleys, forcing water back under tiles
Check sarking (roof underlay):
- Torn or deteriorated foil allows wind-driven rain to enter ceiling cavities
💡 These issues often don’t leak during light rain — only during storms.
4️⃣ How do I find a roof leak if I can’t see damage?
The “Hose Isolation Test”
Leaks often enter higher up the roof than where ceiling stains appear.
Method (requires two people):
- One person inside the roof cavity with a torch
- One person outside with a hose
Process:
- Start wetting the roof at the lowest point near the gutter
- Move upward in 1-metre sections
- Pause between sections until water is observed internally
🎯 This isolates the exact point of water ingress.
5️⃣ Can I re-point roof ridge caps myself?
Yes — if you use flexible pointing only
Modern roof pointing products are pre-mixed and flexible.
Correct method:
- Remove all loose or cracked cement first
- Never apply new pointing over dirty or failing material
- Apply a 3–5mm flexible pointing layer over bedding cement
- Ensure full coverage around the ridge cap collar
Recommended products: Dulux Acratex, Star Point.
6️⃣ How do I temporarily fix a rusty valley iron?
Budget repair without full replacement
Suitable only for small rust holes
Method:
- Wire-brush rust back to clean metal
- Apply a rust converter primer
- Seal with bitumen flashing tape or waterproof membrane coating
🚫 If rust holes exceed the size of a 50-cent coin, full valley replacement is required.
7️⃣ My chimney flashing leaks — do I need a plumber?
Not always
Lead flashing commonly lifts as buildings move.
Fix:
- Carefully re-dress (tap down) the lead flashing
- Apply a bead of grey roof silicone where lead meets brickwork
This prevents water tracking behind the flashing.
8️⃣ Is pressure washing roof tiles safe for DIY?
We strongly advise against DIY pressure washing
Risks include:
- Forcing water under tile laps and flooding insulation
- Extreme slip hazard
- Stripping factory glaze from concrete tiles
9️⃣ What’s the best way to stop moss growing on roof tiles?
Soft-wash chemical treatment (recommended)
Method:
- Apply a moss-killing solution (e.g. “Wet & Forget” or diluted chlorine mix)
- Apply on a dry day
- Allow time — moss dies gradually and washes away naturally
✅ Safer and more effective than pressure washing.
🔟 Can I glue a broken terracotta tile?
No — terracotta tiles must be replaced
Terracotta expands with heat and remains under tension.
- Glued repairs almost always fail
- Replacement is the only reliable solution
💡 Source matching tiles from demolition or reclamation yards. Bring a sample to match the profile.
1️⃣1️⃣ How do I stop leaks around solar panel brackets?
A very common failure point
Installers often grind or drill tiles to fit brackets.
Fix:
- Apply UV-rated silicone around the bracket penetration
- Ensure the rubber Gasket is fully compressed
- Inspect regularly — these seals degrade over time
1️⃣2️⃣ My gutter leaks at the corner — do I need new gutters?
Usually no
Fix:
- Clean the internal gutter join thoroughly
- Remove slime and residue using spirits
- Apply gutter silicone inside the joint only
🚫 External silicone will fail under water pressure.
1️⃣3️⃣ What should I do if my ceiling is sagging from water?
Release the weight immediately
Emergency step:
- Carefully puncture the centre of the bulge
- Catch water in a bucket
This can prevent ceiling collapse.
Aftercare:
- Allow full drying before repairs
- Plaster replacement may still be required
1️⃣4️⃣ Can I paint my roof tiles with normal exterior paint?
No — roof tiles require specialist coatings
Roof surfaces experience extreme temperature changes.
Requirement:
- Use a dedicated roof membrane coating
- Designed to expand and contract without peeling
Standard exterior paint will blister and fail prematurely.
