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Premixed bags of concrete should not be stored outside unless done so temporarily. If you must store your concrete bags outside, the bags should be covered with a tarp, lifted off the ground on a pallet or storage rack, and stored for the shortest time possible to prevent the bag from hardening.
This article will discuss the types of containers concrete comes in, such as plastic, how to store the bags of concrete, and the suggested length of time to store concrete. We will also discuss what happens if your concrete bags get wet.
Why Not Store A Bag Of Concrete Outside?
Bags of ready-to-use concrete contain a mix of fine aggregates and a binding agent — Portland cement. Portland Cement is hygroscopic and chemically attracted to water. Once any form of moisture comes into contact with the bag, the cement will activate and form clumps or, worse, harden completely.
While you may be ready to throw the bag away, there are projects for which you can use the hardened bag.
Concrete Packaging and Storage
Another critical aspect to consider is the packaging. Whether in paper or plastic, storing the bags outdoors should not be for an extended period. Concrete is packaged in either plastic or paper bags, each having pros and cons. This section will discuss the effect storage has on paper and plastic.
Concrete Paper Bags
The most commonly used packaging is a paper bag, as it is more readily available and cheaper to use. This choice is validated by it being more affordable to manufacture, faster to pack the cement into, and ultimately giving us, the user, a cost-effective product.
Catherine Kerninon from EUROSAC and Kennert Johansson initiated a study to investigate paper and plastic cement bags’ shelf life. The paper bag provided an 18-month shelf life, and the plastic bag provided a 19-month shelf life (source).
A paper bag is a favorable option in terms of environmental impact. It has a lower carbon footprint than that of polyethylene cement bags. The study also revealed that the paper bag protected the cement’s key ingredients’ quality, providing a stronger product.
Paper bags have a downside since air can pass through the bag, which means moisture in the atmosphere, such as humidity, can get into the bag, causing it to harden. Paper is also easily damaged by water, and, if dropped, they may tear or rip.
Concrete Plastic Polythene Bags
The use of plastic polyethylene bags has increased recently. They offer better protection from the elements and do not tear or rip as easily.
The shelf life with cement packaged this way is a lot longer than when packaged with a paper bag; generally, the contents last for 180 days, give or take (source).
They also allow you to store the concrete bags outside, but it still needs to be stored in a dry place. These bags are recyclable but not biodegradable.
The downside is that this makes the product cost more and leaves you with a weaker product overall, as shown by the study mentioned above.
Concrete Plastic Buckets
Some quick-set, pre-blended concrete mixtures are available in plastic buckets, and all you need is to add water in and mix. The ready-to-use version of concrete is a convenient option for small DIY projects as it is easy to mix. It already comes in a container, so you don’t need to buy an extra one to make the concrete.
It allows for easy storage, and you can store it outside if needed, as the container will protect it from the elements. If you only use a portion of the product, you can store the rest of the unused powder blend in the container and use it later.
The downside is that this product is more for small DIY projects and not for large projects where high quantities are needed. The cost of the product stored this way is higher due to the container.
Inside or Outside, Which is Best?
Concrete bags can be stored outside successfully by following certain guidelines discussed below. However, it is good to remember that outdoor storage should only be for a short time.
Since bags of concrete attract moisture, it is essential to consider your region’s climate when deciding where to store your bags. Should you live in an area that is humid and rains regularly, outside storage may be problematic.
However, if you live in a dry, arid region, outdoor storage should not pose a problem as long as you follow a few guidelines.
Outdoor Concrete Bag Storage
The first step for successful outdoor storage is to lay down a very large tarp. When you are purchasing your tarp, make sure you buy two.
Now that you have laid down your first tarp, it is a good idea to use a pallet. While not always necessary, a pallet will help raise the bags higher off the ground.
A pallet also allows air to pass under the bags keeping them dryer. It is also an excellent second step to prevent the bags from getting or staying damp as a tarp is not foolproof.
If you are like most homeowners, you won’t have pallets lying around ready to use. While you can purchase pallets on large retail websites such as Amazon, this can be costly, and there are websites dedicated to assisting you in finding pallets for free.
For the next step, once you have stacked the bags, you will take the second large tarp or waterproof covering and place it over the top of the stack of bags. Ensure it is well anchored or taped as tightly to the stack of concrete bags as possible to limit exposure to water and moisture.
The measures and techniques we have described will buy you a small amount of time to store the bags of concrete or cement outside.
Indoor Concrete Bag Storage
The highly water-sensitive cement found in concrete premix is what causes the product to trigger the hardening process. This process makes it vitally important to keep concrete bags out of damp, wet, moist, or highly humid areas, away from rain and flooding, while storing the concrete bags.
Ideally, you should store the bags in a dry and enclosed structure to protect them from rain and moisture. When storing stacked concrete bags for the long term, one idea is to put the smaller bags into an oversized plastic bag and tightly seal it.
Also, do not place the bags directly on concrete or wood floors; preferably, place the bags on a wooden pallet to raise the bags off the floor. If you want to protect them further, you could even put down a tarp and then place your pallets.
Floors directly touching the ground are porous, and moisture can be introduced to the bags even though indoors.
Where to Store Concrete Bags
When storing for a long time, make sure not to put the bags upright or on their narrow sides but, instead, laid flat with their broadsides down.
Doing this helps to even out the weight simultaneously, allowing for more bags to be stably stacked one on top of another, therefore reducing the amount of air contact with the significant surface area of the bags (source).
Do not store the cement bags with other heavy chemicals like fertilizers or any other strong chemical products. Cross-contamination may become a problem as it can significantly affect the concrete screen’s (finish) quality, performance, or tensile strength when used.
It is vital to provide an adequate amount of ventilation when storing concrete on pallets in a warehouse. The correct ventilation prevents the buildup of damp air forming under the bags.
Always rotate the stock of concrete or cement bags on a first-in-first-out basis to prevent warehouse-pack; this is when the concrete premix’s cement gets lumpy as it settles and hardens.
To help rotate stock, check the manufacturers’ date (MFD) and then use the oldest store over the fresh supply.
Do your best to store leftover cement as carefully as you can. It would be best to use any open or torn concrete bags first before opening a new one. Ideally, it would be best if you rebagged them in plastic bags or heavy-duty garbage bags, with the openings sealed securely with string or tape (source).
There are ways to keep concrete or cement outside with the correct measures, though it can only be for a short period. Still, this is less than ideal as it will cause the product to lose its durability and probably result in hardening before you’re ready to use it.
The best location would be indoors in a dry storeroom, warehouse, or shed perched on a pallet. Placing it on a pallet allows air to flow under the bags to keep them dry underneath and prevent water from being absorbed from the ground.