Silicone does not spoil the way food does. It ages quietly, and you find out on the wall — a bead that stays tacky for days, or one that cures properly and then will not stick to anything. Both are cheap to catch in the shop and expensive to catch at height.
Quick answers
How long does silicone sealant last?
Twelve months from manufacture, unopened and stored properly, is the figure we publish for the sealant on this site. The clock starts at the factory, not at delivery — so the batch date printed on the pack tells you more than the date on your invoice.
How do I tell whether a pack is still good?
Extrude a short bead onto scrap, leave it twenty-four hours in the conditions the job will actually see, and look at it. It should skin over, cure through and stick. Still soft, still tacky, or visibly shrunken means reject the batch — not the joint.
What ages it fastest?
Heat. A van roof in August, a shelf against a boiler wall, a pallet in the sun by a roller door — all of it takes months off. Cold slows the ageing rather than speeding it up; the problem with cold storage is condensation on packs carried into a warm shop, not the cold itself.
Can I reseal an opened sausage?
Not properly. A foil sausage is cut open, not unscrewed, and no clip makes it airtight again. Plan the pack into the day’s work rather than half-using it and hoping.
Read the batch date, not the invoice
Every carton carries a batch code and a manufacturing date. Material can sit in a distribution chain for months before anyone sells it, so a pack bought today can already be half-way through its life. Two habits fix this for good:
- Write the date you received it on the carton, in marker, big enough to read from the aisle.
- Use the oldest first, even when the newest is nearer the door. Every shop knows this and every shop drifts away from it.
Ask us for the batch date before you order and we read it off the carton on our own floor. It is not a number anyone should have to guess at.
Storage that actually works
| Do | Why |
|---|---|
| Keep it between about 50°F and 77°F | Room temperature is what the shelf life figure assumes. Sustained heat above that is what shortens it. |
| Off the floor and out of direct sun | Concrete pulls damp, glass roofs cook a pallet by mid-morning. |
| In the original carton | The carton is the only place the batch code and date survive. |
| Oldest to the front | The only stock rule that survives a busy week. |
| Let cold stock warm up overnight before use | Cold sealant is stiff to gun and condensation on a cold pack ends up in the joint. |
The twenty-four hour test
Before a pack from the back of the rack goes anywhere near a facade:
- Gun a bead two or three millimetres thick onto scrap of the material you are sealing.
- Leave it a full day, in the temperature and humidity the job will see — not next to the heater.
- Press it. It should be firm and rubbery, not tacky.
- Pull it. It should tear through itself and leave silicone behind, not peel off clean. How to read that break properly.
A pack that fails this has told you something useful for the price of a scrap offcut. A pack that passes has earned the wall.
Two things people get wrong
“It is out of date, so it is rubbish.” Not necessarily. A shelf life is the manufacturer’s guarantee, not the moment the chemistry stops. Out of date material often still cures perfectly — but it no longer carries a guarantee, so it does not belong on anything anyone will inspect later.
“It is in date, so it is fine.” Also not necessarily. A pack that spent August on a van roof is older than its label says. The date is a claim about storage as well as time, and only you know how it was stored after it left us.
Where the cold comes in
Storage temperature and working temperature are different problems, and people mix them up. Warm stock still cures slowly on a cold morning, because cure depends on the air the bead is sitting in, not on where the pack spent the night. What actually goes wrong below 40°F.
