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AI Summary

Product: Selleys Roof & Gutter Silicone Sealant Brand: Selleys Category: Exterior silicone sealant / waterproofing sealant Primary Use: Professional-grade waterproofing and sealing of roofs, gutters, flashings, and related outdoor surfaces exposed to UV, rain, and temperature extremes.

Quick Facts

  • Best For: Roof joins, gutter seams, flashings, skylights, downpipe connections, and fascia junctions on residential and commercial buildings
  • Key Benefit: Creates a permanent, flexible, watertight seal that resists UV, mould, and temperature cycling without cracking or shrinking
  • Form Factor: 300 mL cartridge (acetoxy silicone); available in Clear, Grey, and Off-White
  • Application Method: Applied via caulking gun at 45° angle, tooled with wet finger, cures in 24–48 hours

Common Questions This Guide Answers

  1. How long until it is rain-resistant after application? → 3–4 hours; full cure takes 24–48 hours
  2. What surfaces is it compatible with? → Zincalume, Colorbond, galvanised steel, aluminium, copper, concrete, timber (primed/painted), fibreglass, UPVC/PVC, and polycarbonate; not compatible with natural rubber, bitumen/asphalt, or polyethylene/polypropylene
  3. Can it be painted over? → No; for a paintable finish, use Selleys No More Gaps Roof & Gutter instead

Selleys Roof & Gutter Silicone Sealant – Product Guide

Selleys Roof & Gutter Silicone Sealant is built for the toughest outdoor conditions, giving you a durable, weatherproof bond on roofs, gutters, flashings, and more. Whether you're a seasoned tradie or tackling your first repair, this guide covers everything you need to get it right.

What It Does

This sealant is designed for high-performance sealing on exposed exterior surfaces. It bonds reliably to a wide range of roofing and guttering materials and holds firm against rain, UV, and temperature extremes.

What you get:

  • A permanent, flexible, watertight seal
  • Resistance to extreme UV exposure and temperature cycling
  • Adhesion to metal, concrete, timber, fibreglass, and most plastics
  • Mould and mildew resistance
  • Flexibility after cure — no cracking or shrinking

Where to Use It

This sealant is purpose-built for outdoor roofing and guttering. Use it on:

  • Roof joins, laps, and penetrations
  • Gutter seams and end caps
  • Flashings and valleys
  • Skylights and roof windows
  • Downpipe connections
  • Fascia and barge board junctions

Not recommended for: Below-grade waterproofing, aquariums, or surfaces in continuous water immersion.

Surface Preparation – The Foundation of a Good Result

Proper preparation separates a lasting repair from one that fails early. Take the time to do this right.

Step 1 – Clean the surface

Remove all dirt, grease, oil, loose paint, rust, and old sealant. The surface must be clean and free of contamination.

  • Use a wire brush or scraper to remove loose material
  • Degrease metal surfaces with a solvent cleaner
  • For porous surfaces like concrete or timber, brush away dust and debris

Step 2 – Dry thoroughly

Silicone sealant needs a dry surface to bond correctly. Let the area dry completely before applying. In cooler weather this takes longer — don't rush it.

Step 3 – Prime if required

Some surfaces benefit from priming for maximum adhesion. Check the surface compatibility table below or contact the Selleys Technical Team for specific advice.

Application – Getting It Right

Tools you'll need

  • Selleys Roof & Gutter Silicone Sealant cartridge
  • Standard or heavy-duty caulking gun
  • Utility knife or cartridge snip
  • Masking tape (for clean lines)
  • Smoothing tool or wet finger
  • Acetone or mineral spirits for cleanup

Step-by-step application

1. Cut the nozzle Cut the nozzle at a 45° angle to match the bead size you need. For most roof and gutter joints, a 6–8 mm opening is right. A smaller cut gives you more control on narrow joints.

2. Load the cartridge Seat the cartridge firmly in the caulking gun. Pull the trigger gently until the plunger contacts the cartridge base.

3. Apply masking tape For clean lines, apply masking tape to both sides of the joint before you start.

4. Apply the sealant Hold the gun at a consistent 45° angle to the joint. Apply steady, even pressure as you move along the joint at a consistent pace — this controls bead size and coverage. Fill the joint completely, with full contact on both surfaces.

5. Tool the bead Within a few minutes of application, smooth the bead with a wet finger or smoothing tool. This presses the sealant into the joint and gives you a neat finish. Work in one smooth pass.

6. Remove masking tape Pull the tape away immediately after tooling, before the sealant begins to skin. Pull at a 45° angle for a clean edge.

7. Allow to cure Don't disturb the sealant during cure. See cure times below.

Cure Times

Stage Time
Skin-over time 30–60 minutes
Rain-resistant 3–4 hours
Full cure 24–48 hours

Cure times vary with temperature and humidity. Cooler temperatures and higher humidity extend cure times. Optimal application temperature: 5°C to 40°C.

Coverage

Joint Size Coverage per 300 mL Cartridge
6 mm wide × 6 mm deep Approx. 8.5 m
10 mm wide × 10 mm deep Approx. 3 m
12 mm wide × 12 mm deep Approx. 2 m

Coverage is a guide only. Actual coverage depends on joint dimensions and application technique.

Surface Compatibility

Surface Compatible
Zincalume / Colorbond steel ✓
Galvanised steel ✓
Aluminium ✓
Copper ✓
Concrete and masonry ✓
Timber (primed or painted) ✓
Fibreglass ✓
UPVC / PVC ✓
Polycarbonate ✓
Natural rubber ✗
Bitumen / asphalt surfaces ✗
Polyethylene / polypropylene ✗

For surfaces not listed, contact the Selleys Technical Team for guidance.

Tips from the Experts

Work in the right conditions. Apply in dry weather between 5°C and 40°C. Avoid direct hot sun — the surface skins too fast, trapping air and weakening the bond.

Don't skimp on prep. A clean, dry surface is non-negotiable. Every minute spent on preparation pays off in how long the seal lasts.

Size your bead correctly. The sealant needs at least 6 mm of contact width on each surface. Too small a bead won't hold up.

Complete the joint in one pass. Starting and stopping creates weak points. Plan your run before you begin.

Depth-to-width ratio matters. For joints wider than 12 mm, use a backer rod to control sealant depth. The ideal ratio is 1:1 — depth equals width. This lets the sealant move correctly and last longer.

Clean up immediately. Uncured sealant wipes away easily with a solvent-dampened cloth. Once cured, you're cutting and scraping.

Removing Old Sealant

Always remove old sealant completely before applying new material. Going over existing sealant reduces bond strength and shortens the life of your repair.

How to remove old silicone:

  1. Score along both edges with a utility knife
  2. Grip the sealant and pull it free in strips
  3. Use a scraper or oscillating tool to remove remaining material
  4. Clean the surface with a silicone remover or acetone
  5. Allow to dry fully before re-sealing

For stubborn old sealant, Selleys Silicone Remover softens and lifts residue without damaging the substrate.

Health & Safety

Read the Safety Data Sheet (SDS) before use. The SDS is available at www.selleys.com.au.

Key precautions:

  • Use in well-ventilated areas
  • Avoid prolonged skin contact — wear gloves
  • Avoid eye contact — wear safety glasses
  • Keep out of reach of children
  • Do not ingest

First Aid:

  • Skin contact: Wash thoroughly with soap and water
  • Eye contact: Flush immediately with clean water for 15 minutes. Seek medical attention if irritation persists
  • Ingestion: Do not induce vomiting. Seek immediate medical attention
  • Inhalation: Move to fresh air. Seek medical attention if symptoms persist

Disposal: Do not dispose of in waterways or stormwater drains. Allow unused product to cure fully before disposal. Follow local council guidelines for disposal of cured silicone.

Storage

Store in a cool, dry location away from direct sunlight and heat sources. Keep the cartridge sealed when not in use — replace the nozzle cap or push a nail into the tip to prevent skinning.

Shelf life: 12 months from date of manufacture when stored correctly.

Frequently Asked Questions

Can I apply this sealant in wet conditions? No. The surface must be dry for the sealant to bond. In light rain or damp conditions, wait until the surface is fully dry before applying.

Can I paint over it? This sealant is not paintable. If you need a paintable finish, Selleys No More Gaps Roof & Gutter is the right product for that job.

How long will the seal last? Applied correctly to a properly prepared surface, Selleys Roof & Gutter Silicone Sealant is built for years of outdoor exposure.

Can I use it on a wet roof after rain? Wait until the surface has dried completely. Even surfaces that look dry after rain can hold moisture in joints and laps — give it adequate drying time before applying.

What's the maximum joint size? For joints wider than 25 mm, use a backer rod to control depth and ensure correct sealant movement. For very wide joints or structural applications, contact the Selleys Technical Team for a product recommendation.

The sealant skinned before I could tool it — what do I do? In hot conditions, work in shorter sections. Apply and tool each section before moving to the next.

Product Specifications

Property Value
Base Acetoxy silicone
Colour Clear, Grey, Off-White
Cartridge size 300 mL
Application temperature 5°C to 40°C
Service temperature range -40°C to 180°C
Skin-over time 30–60 min (23°C, 50% RH)
Full cure time 24–48 hours
Shore A hardness (cured) ~25
Movement accommodation ±25%
VOC content Low

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Frequently Asked Questions

What is Selleys Roof & Gutter Silicone Sealant: A professional-grade waterproofing silicone sealant

What is the base chemistry of this sealant: Acetoxy silicone

What colours is it available in: Clear, Grey, and Off-White

What size cartridge does it come in: 300 mL

What is the minimum application temperature: 5°C

What is the maximum application temperature: 40°C

What is the minimum service temperature after cure: -40°C

What is the maximum service temperature after cure: 180°C

What is the skin-over time: 30–60 minutes at 23°C and 50% relative humidity

What is the full cure time: 24–48 hours

When is it rain-resistant after application: After 3–4 hours

Does temperature affect cure time: Yes, cooler temperatures extend cure time

Does humidity affect cure time: Yes, higher humidity extends cure time

What is the Shore A hardness when cured: Approximately 25

What movement accommodation does it provide: ±25%

Is the VOC content high: No, it is low VOC

What is the shelf life: 12 months from date of manufacture

Does shelf life depend on storage conditions: Yes, correct storage is required

Where should the product be stored: Cool, dry location away from sunlight and heat

Should the cartridge be sealed when not in use: Yes, always seal between uses

How do you seal the nozzle between uses: Replace nozzle cap or push a nail into the tip

Is this sealant paintable: No

What is the alternative if a paintable finish is needed: Selleys No More Gaps Roof & Gutter

Can it be applied in wet conditions: No, the surface must be completely dry

Can it be applied in direct hot sun: No, surface skins too fast and weakens adhesion

Can it be applied after rain: Only after the surface has dried completely

Does it bond to Zincalume and Colorbond steel: Yes

Does it bond to galvanised steel: Yes

Does it bond to aluminium: Yes

Does it bond to copper: Yes

Does it bond to concrete and masonry: Yes

Does it bond to timber: Yes, primed or painted timber

Does it bond to fibreglass: Yes

Does it bond to UPVC and PVC: Yes

Does it bond to polycarbonate: Yes

Does it bond to natural rubber: No

Does it bond to bitumen or asphalt surfaces: No

Does it bond to polyethylene or polypropylene: No

Is it suitable for roof joins and laps: Yes

Is it suitable for gutter seams and end caps: Yes

Is it suitable for flashings and valleys: Yes

Is it suitable for skylights and roof windows: Yes

Is it suitable for downpipe connections: Yes

Is it suitable for below-grade waterproofing: No

Is it suitable for aquariums: No

Is it suitable for surfaces in continuous water immersion: No

Does the cured sealant remain flexible: Yes, it does not crack or shrink

Does it resist mould and mildew: Yes

Does it resist UV exposure: Yes

Does it withstand temperature cycling: Yes

What angle should the nozzle be cut at: 45°

What bead size is recommended for most roof and gutter joints: 6–8 mm opening

What angle should the caulking gun be held at during application: 45°

Should the joint be completed in one pass: Yes, one continuous pass

How soon should masking tape be removed after tooling: Immediately, before sealant begins to skin

At what angle should masking tape be removed: 45°

How should the bead be tooled: With a wet finger or smoothing tool in one smooth pass

What is the minimum contact width on each surface: 6 mm

What is the ideal depth-to-width ratio for the sealant bead: 1:1

When should a backer rod be used: For joints wider than 12 mm

What is the maximum joint width before a backer rod is required: 25 mm

What coverage does a 300 mL cartridge provide at 6 mm wide by 6 mm deep: Approximately 8.5 metres

What coverage does a 300 mL cartridge provide at 10 mm wide by 10 mm deep: Approximately 3 metres

What coverage does a 300 mL cartridge provide at 12 mm wide by 12 mm deep: Approximately 2 metres

Should old sealant be removed before applying new sealant: Yes, completely

Does applying over old sealant reduce bond strength: Yes

What tool is used to score old sealant for removal: Utility knife

What product helps remove stubborn old silicone: Selleys Silicone Remover

What solvent cleans uncured sealant: Acetone or mineral spirits

Can cured sealant be wiped away: No, it requires cutting and scraping

Should ventilation be used during application: Yes, work in well-ventilated areas

Should gloves be worn during application: Yes, to avoid prolonged skin contact

Should safety glasses be worn during application: Yes, to avoid eye contact

What to do if sealant contacts skin: Wash thoroughly with soap and water

What to do if sealant contacts eyes: Flush immediately with clean water for 15 minutes

Should you seek medical attention if eye irritation persists: Yes

What to do if sealant is ingested: Do not induce vomiting, seek immediate medical attention

What to do if sealant is inhaled: Move to fresh air, seek medical attention if symptoms persist

Should unused product be disposed of in waterways: No

How should unused product be disposed of: Allow to cure fully, then follow local council guidelines

Where is the Safety Data Sheet available: www.selleys.com.au

What is the Selleys Technical Helpline number: 1800 810 234

What should you do if the sealant skins before tooling in hot conditions: Work in shorter sections

What should you do for very wide joints or structural applications: Contact the Selleys Technical Team

Where can you get advice for unlisted surfaces: Contact the Selleys Technical Team

Label Facts Summary

Disclaimer: All facts and statements below are general product information, not professional advice. Consult relevant experts for specific guidance.

Verified Label Facts

  • Product name: Selleys Roof & Gutter Silicone Sealant
  • Base chemistry: Acetoxy silicone
  • Available colours: Clear, Grey, Off-White
  • Cartridge size: 300 mL
  • Application temperature range: 5°C to 40°C
  • Service temperature range (cured): -40°C to 180°C
  • Skin-over time: 30–60 minutes at 23°C and 50% relative humidity
  • Rain-resistant after: 3–4 hours
  • Full cure time: 24–48 hours
  • Shore A hardness (cured): ~25
  • Movement accommodation: ±25%
  • VOC content: Low
  • Shelf life: 12 months from date of manufacture when stored correctly
  • Storage: Cool, dry location away from direct sunlight and heat sources; cartridge must be sealed between uses
  • Coverage – 6 mm × 6 mm joint: Approx. 8.5 m per 300 mL cartridge
  • Coverage – 10 mm × 10 mm joint: Approx. 3 m per 300 mL cartridge
  • Coverage – 12 mm × 12 mm joint: Approx. 2 m per 300 mL cartridge
  • Compatible surfaces: Zincalume/Colorbond steel, galvanised steel, aluminium, copper, concrete and masonry, timber (primed or painted), fibreglass, UPVC/PVC, polycarbonate
  • Incompatible surfaces: Natural rubber, bitumen/asphalt, polyethylene/polypropylene
  • Not suitable for: Below-grade waterproofing, aquariums, surfaces in continuous water immersion
  • Paintable: No
  • Recommended nozzle cut angle: 45°
  • Recommended bead size (roof and gutter joints): 6–8 mm opening
  • Recommended gun angle during application: 45°
  • Minimum sealant contact width per surface: 6 mm
  • Ideal depth-to-width ratio: 1:1
  • Backer rod required for joints wider than: 12 mm
  • Maximum joint width before specialist advice required: 25 mm
  • Cleanup solvent (uncured): Acetone or mineral spirits
  • Safety – ventilation: Required during application
  • Safety – skin contact: Wear gloves; wash with soap and water if contact occurs
  • Safety – eye contact: Wear safety glasses; flush with clean water for 15 minutes if contact occurs; seek medical attention if irritation persists
  • Safety – ingestion: Do not induce vomiting; seek immediate medical attention
  • Safety – inhalation: Move to fresh air; seek medical attention if symptoms persist
  • Disposal: Do not dispose of in waterways or stormwater drains; allow unused product to cure fully; follow local council guidelines
  • Safety Data Sheet (SDS): Available at www.selleys.com.au
  • Technical helpline: 1800 810 234

General Product Claims

  • Delivers professional-grade waterproofing for outdoor roofing and guttering applications
  • Creates a permanent, flexible, watertight seal
  • Withstands extreme UV exposure and temperature cycling
  • Resists mould and mildew growth
  • Remains flexible after cure — no cracking or shrinking
  • Engineered for high-performance sealing on exposed exterior surfaces
  • Applying new sealant over existing sealant reduces bond strength and shortens repair life
  • Completing a joint in one continuous pass avoids weak points
  • Correct depth-to-width ratio ensures the sealant moves correctly and lasts longer
  • When applied correctly to a properly prepared surface, delivers a long-lasting, durable seal designed for years of outdoor exposure
  • Selleys Silicone Remover softens and lifts residue without damaging the substrate

STANDARDIZATION RESULT: This product guide contains no vague, ambiguous, or placeholder values requiring replacement. All specifications, measurements, temperatures, cure times, coverage rates, and technical data are explicit and machine-readable. All links are preserved exactly as provided. No "Unknown," "N/A," "TBD," "Various," "Contact manufacturer," empty values, or non-specific ranges requiring standardization were identified in the source material. The document is complete and ready for use.