What is Selleys Pro Trade Roof & Gutter Silicone, and where should you use it?

Selleys Pro-Trade Roof & Gutter is a high quality 100% neutral (oxime) cure silicone for general purpose roof and gutter and weather sealing, where excellent adhesion and long-term reliability are required. It reacts with atmospheric moisture to produce a form-in-place silicone rubber seal, and it can be used as both an adhesive and a sealant.

The specification that decides most roofing jobs is on the label: it is AS4020 approved for potable water, and it will not corrode metals. If the gutter you are repairing feeds a rainwater tank, that potable water approval is the reason to choose this product rather than a general-purpose silicone. The neutral cure chemistry is the reason it is safe against the metals a roof is made from.

Technical specification

Property	Typical result
Technology	Neutral (oxime) cure silicone
Colour	Clear, grey, black
Density	1.04
Application temperature	Minimum 5°C
Skin time (25°C / 50% RH)	5 to 10 minutes
Cure rate	10mm in 5 to 7 days
Slump (JIS A 1439)	No slump (0.1% max)
Tensile strength (JIS K 6249)	2.0 MPa
Shore A hardness (ASTM D2240)	28
Elongation at break (JIS K 6249)	400%
Movement capability	±25%
Service temperature	-60°C to 170°C
VOC content (SCAQMD Method 304-91)	31 g/L
Standards	BS 5889 approved; AS4020 approved for potable water
Packaging	300g cartridge in clear, grey or black

These are indicative data only, not intended for the preparation of specifications. Where the product page and the technical data sheet differ, the figures above follow the data sheet.

What the key numbers mean in practice

The skin time of 5 to 10 minutes and the matching tooling time of 5 to 10 minutes give you a genuinely short working window. On a roof that means beading and tooling in short sections rather than running a whole gutter seam and coming back. Once the skin starts to form, tooling tears the surface instead of smoothing it, and on a joint that has to shed water a torn surface is a leak path.

The tack free time is approximately one hour — the point at which the bead stops picking up dust and debris, which on an exposed roof is worth knowing. It is not the point at which the joint is cured. The cure rate of 10mm in 5 to 7 days describes how deep the cure travels, and because the product cures by reacting with atmospheric moisture, a joint enclosed on all sides cures more slowly still.

±25% movement capability with 400% elongation at break is what keeps a roof joint intact through daily thermal cycling. Sheet metal roofing moves measurably between a cold morning and a hot afternoon, and a sealant that cannot stretch a quarter of the joint width will eventually pull away from one face. The no-slump rating (0.1% maximum) means a bead on a vertical flashing or fascia holds its shape rather than sagging before it skins.

A service temperature range of -60°C to 170°C covers roof surface temperatures with plenty of margin. VOC content of 31 g/L sits inside the GBCA limit of maximum 50 g/L, which matters on commercially specified work.

Where to use it

Pro-Trade Roof & Gutter is suitable for general purpose roof and gutter and weather sealing, and also for industrial, potable water and automotive sealing applications. The product page lists roofing, gutters and flashings, and notes excellent adhesion to metals and roofing substrates.

It is described as ideal for most common building substrates, including glass, most metals (aluminium, steel and the like), concrete, brick, plasterboard, wood, ceramics, most plastics and most powder coated surfaces. Pre-testing on substrates is recommended, and the product page adds that it should not be used on polyethylene, polypropylene or PTFE.

Surface preparation

Surfaces must be clean, dry, and free of dirt, grease, oil or water. Metal and glass surfaces should be cleaned with general-purpose thinners or mineral turpentine and allowed to dry. The product page adds the roofing-specific instruction to clean all surfaces of dirt, oil and rust — silicone bonds to what it touches, and a bead applied over loose rust leaves with the rust.

How to apply it

1. Clean the surface so it is dry and free of dirt, grease, oil, water and rust. Clean metal and glass with thinners or mineral turps and let them dry.
2. Prime if the substrate requires it, and allow the primer to dry before applying the sealant.
3. Use approved backing material for joints over 10mm deep.
4. Cut the nozzle at a 45 degree angle to the bead width you want.
5. Apply to the substrate with a sealant gun, working the bead directly into the joint or seam.
6. Tool within 5 to 10 minutes. For a neat appearance, use masking tape and remove it before the sealant has skinned over.
7. Allow the sealant to cure before water exposure.

Limitations — where Pro-Trade Roof & Gutter should not be used

These are the manufacturer's stated limits:

• Not suitable for structural glazing.
• Not suitable for submerged joints where porous substrates permit water to the bond interface.
• Not suitable for aquarium construction.
• Should not be applied in contact with bituminous materials or some rubber products. These can contain components that migrate into the sealant and cause staining or reduced performance — a real risk on roofs, where bituminous membranes and flashing tapes are common.
• Complete painting before applying the sealant, as it cannot be successfully painted over.

The product page adds that it should not be used on polyethylene, polypropylene or PTFE.

Clean up and storage

Uncured sealant cleans up with mineral turpentine — do it as you go, given the short skin time. Storage life is 12 months from the date of manufacture if stored below 28°C.

Hazard classification

Classified as hazardous under Safe Work Australia GHS 7, with the signal word Warning.

• Skin sensitisation — Category 1. H317: may cause an allergic skin reaction.
• Skin irritation — Category 2. H315: causes skin irritation.
• Flammable liquids — Category 4. H227: combustible liquid.

It is not classified as Dangerous Goods under the Australian Code for the Transport of Dangerous Goods by Road & Rail, or under New Zealand NZS5433. It is classified as a C1 combustible liquid for the purposes of storage and handling under AS 1940, and state regulations should be consulted for specific storage requirements.

What is in it

Chemical entity	CAS number	Proportion (w/w)
2-Butanone, O,O',O"-(methylsilylidyne)trioxime	22984-54-9	1–10%
2-Butanone, O,O',O"-(ethenylsilylidyne)trioxime	2224-33-1	<1%
Cyclotetrasiloxane, octamethyl- (D4)	556-67-2	<1%
N-[3-(Trimethoxysilyl)propyl]ethylenediamine	1760-24-3	<1%
Ingredients determined to be non-hazardous or below reporting limits	—	Balance

Start with the apparent contradiction, because it is the useful part. The page above sells this sealant on its AS4020 approval for potable water, and the classification says it irritates and sensitises skin. Both are true, and they describe different materials. AS/NZS 4020 tests the cured sealant sitting in contact with water; the GHS classification describes the uncured paste coming out of the nozzle. The oxime cure system is consumed as the bead sets. So the hazard window is the hour you spend running the bead, not the twenty years the gutter spends feeding a rainwater tank — and the potable-water approval is not undermined by anything on this list.

The two butanone-oxime silanes are the neutral cure system, and they are the reason this product does what the page says: they release methyl ethyl ketoxime rather than acetic acid as the bead cures, which is what makes the sealant safe against the metals a roof is made from. They are also, on the evidence of the classification, where the skin hazard comes from — oxime chemistry is the component class that carries H317 across this family of neutral-cure sealants. Treat that as informed inference rather than a sourced statement.

Sensitisation is not irritation, and this product carries both. The Category 2 irritation is the redness and soreness you get while the material is on your skin, and it clears once you wash it off. The Category 1 sensitisation is different: it is the immune system learning to react to the material, it is generally permanent once acquired, and afterwards a far smaller exposure will set it off, with each contact tending to be worse than the last. It builds from repeated ordinary contact rather than one bad day. A roofer tooling flashings and gutter seams bare-fingered, job after job, is running exactly that exposure pattern.

The practical instruction follows: gloves, and tool with a tool. Note too that the page directs you to clean up uncured sealant with mineral turpentine — a solvent-soaked rag is a very efficient way to get sealant residue across the backs of both hands, so clean the work, not your skin. H227 combustible is the mildest flammability class; the material will burn if ignited but is undeclared for transport. It still means keeping cartridges out of a hot vehicle cab and away from a roofer's torch or grinder sparks, and the AS 1940 C1 storage label will matter to anyone holding trade quantities.

Protection

• Gloves — the important one, given the sensitisation classification. Nitrile rubber is indicated as suitable for intermittent contact; glove construction and site conditions vary, so make the final assessment yourself.
• Eye protection — chemical goggles, or eye and face protection.
• Clothing — overalls and safety shoes.
• Ventilation — natural ventilation is adequate in normal use; avoid breathing dust, fume, mist, vapour or spray. Take care in an enclosed roof space or a box gutter, which are not open air.
• Wash hands before smoking, eating, drinking or using the toilet, and wash contaminated clothing and protective equipment before storing or re-using them.
• Storage — the page above adds: below 28°C, and 12 months from the date of manufacture.

First aid

Exposure	What to do
Skin	Effects may be delayed, so act promptly. Remove contaminated clothing and flush the skin and hair with running water. Keep flushing until the Poisons Information Centre or a doctor tells you to stop, or for at least 15 minutes, then get to a doctor or hospital. For gross contamination, drench immediately with water and remove all clothing. For skin burns, cover with a clean dry dressing until medical help arrives; if blistering occurs, do not break the blisters. Seek medical assistance if swelling, redness, blistering or irritation occurs.
Eyes	Hold the eyelids apart and flush the eyes continuously with running water. Keep flushing until the Poisons Information Centre or a doctor tells you to stop, or for at least 15 minutes, then get to a doctor or hospital.
Inhalation	Move the person to fresh air without becoming a casualty yourself. Remove contaminated clothing and loosen the rest, let them settle into the most comfortable position and keep them warm and at rest until fully recovered. Seek medical advice if effects persist.
Swallowed	Rinse the mouth with water. Do not induce vomiting. Give a glass of water to drink. Never give anything by mouth to an unconscious person. If vomiting occurs, give further water and seek medical advice.

If poisoning occurs, contact a doctor or the Poisons Information Centre — 131 126 in Australia, 0800 764 766 in New Zealand — with the container to hand. Selleys emergency line: 1800 220 770 in Australia, 0800 220 770 in New Zealand.

Common questions about Selleys Pro Trade Roof & Gutter Silicone

Is it safe for a rainwater tank?

Yes. It is AS4020 approved for potable water, and potable water sealing is one of its listed applications.

How long do I have to tool the bead?

Tooling time is 5 to 10 minutes, and the skin forms in the same window. Work in short sections.

When is it tack free?

Approximately one hour after application. That is not the same as cured.

How long until it is fully cured?

The cure rate is 10mm in 5 to 7 days, so it depends on the depth of the bead. Allow it to cure before exposing the joint to water.

Will it corrode my gutter or flashing?

No. It is a neutral (oxime) cure silicone and will not corrode metals.

Can I paint over it?

No. It cannot be successfully painted over — complete any painting before you seal.

How much movement will it take?

±25%.

Can I apply it over a bituminous membrane or flashing tape?

No. It should not be applied in contact with bituminous materials or some rubber products, which can cause staining or reduced performance.

Will it stick to plastic?

It suits most plastics, with pre-testing recommended, but the product page excludes polyethylene, polypropylene and PTFE.

What colours does it come in?

A 300g cartridge in clear, grey or black.

How long can I keep it?

12 months from the date of manufacture, stored below 28°C. Note that the product page gives a storage figure of below 30°C; the technical data sheet's 28°C is the stricter and more current figure.

What are the alternatives in this range?

Compare it against Pro Trade All Purpose Silicone and Pro Trade Wet Area Silicone, or see the full roofing silicone range.