How can I stop cement going off in the bag?
- Thread starter Jon Hill
- Start date
No i mean out of date, as in the date they put on the side of the bags. Whilst of course it's a belt and brace's approach they put it on there for a reason.
Why take the risk of saving a few pounds and having to re-do work cause it didn't go off properly.
Why take the risk of saving a few pounds and having to re-do work cause it didn't go off properly.
If the bags have been kept completely dry then they should be fine. Plastic bags of cement can last a year stored inside out of the cold and still be fine - although paper bags would probably not last as long because humidity will eventually breach them and once the reaction starts you cannot stop it.
Wisdom used to say that if there were no lumps in the cement is was good to use, but in reality it is a bit more complicated than that. You could probably use that test for basic concrete without any problems. If using for mortar then test it first, and for render it probably isn't worth taking the risk for just a few £s.
The reason that cement carries a 'manufactured on' dated and a 'use by' date is because of the Chromium (VI) Directive (2003/53/EC), and not because the other properties of the product goes off.
This Directive (Law) was issued in order to minimise the risk of allergic dermatitis from the use of cement.
The 2 month period is due to the use of additives in the cement to reduce the production of chromium (VI) when the cement is mixed with water. These additives become less effective with time and it is considered that after 2 months it cannot be ensured that the chromium (VI) levels would be beow 2 parts per million.
If you are an employee, your employer is breaking various H&S laws if you use the cement after the use by date. If you are a diy-er, it's entirely up to you, although the seller of the cement isn't allowed to sell it after the use by date either.
You should always wear gloves and goggles when handling cement anyway as it is nasty stuff when it gets in your eyes. If it doesn't come into contact with your skin then the chromium (VI) levels are irrelavent.
Wisdom used to say that if there were no lumps in the cement is was good to use, but in reality it is a bit more complicated than that. You could probably use that test for basic concrete without any problems. If using for mortar then test it first, and for render it probably isn't worth taking the risk for just a few £s.
The reason that cement carries a 'manufactured on' dated and a 'use by' date is because of the Chromium (VI) Directive (2003/53/EC), and not because the other properties of the product goes off.
This Directive (Law) was issued in order to minimise the risk of allergic dermatitis from the use of cement.
The 2 month period is due to the use of additives in the cement to reduce the production of chromium (VI) when the cement is mixed with water. These additives become less effective with time and it is considered that after 2 months it cannot be ensured that the chromium (VI) levels would be beow 2 parts per million.
If you are an employee, your employer is breaking various H&S laws if you use the cement after the use by date. If you are a diy-er, it's entirely up to you, although the seller of the cement isn't allowed to sell it after the use by date either.
You should always wear gloves and goggles when handling cement anyway as it is nasty stuff when it gets in your eyes. If it doesn't come into contact with your skin then the chromium (VI) levels are irrelavent.
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