The amount of ballast you need depends on various factors, such as the type of project, the size of the area, and the specific requirements. As a general guideline, you’ll need something about 1,750 kg to 1,800 kg (1.75 to 1.8 tons) of ballast per cubic meter of concrete.

Ballast is a dense mixture of sand and gravel crushed small rock stone that’s form rough coarse aggregate used in extensive range of Construction application, primary it is used for heavy duty work and making concrete.

Typically, the weight of ballast is about 1.75 tons per cubic meter or 1750 kg/ m3. It is available in a small bag of 25kg which yields volume about 0.0143 and large bag known as bulk bag, or jumbo bag which weighs about 850 to 875 kilograms and yields volume about 0.5m3.

**How much ballast do i need for concrete**

For example, how much ballast needed for 5 metre long, 4 metre wide and 100 mm deep slab. Here’s are calculation steps:

- Convert thickness of slab in meter: Divide the thickness in mm by 1000, like 100/1000 = 0.1m
- Estimate volume of slab in m3: Multiply length x width (w) x depth (d). So, if you have volume of slab = 5m × 4m × 0.1m = 2m3
- Determine how much ballast you need: As a general guideline, you can use about 1,750 kg to 1,800 kg of ballast per cubic meter. So, for 2 cubic metres, you will need 3,500 kg of ballast.
- Estimate of ballast in bulk or small bag:- Divide your ballast amount by bag size. Take the amount of ballast you require and divide it by the size of the bag, so 3,500 kgs of ballast in 25 kg bags will work out to 140, or 4 bulk bags of ballast (each bulk bag weighs about 875 kg).

Therefore, you’ll need something like 140 x 25kg bags or 4 x 875kg bulk bags of ballast to create 2m3 of concrete, while for 2m3 concrete you’d need approximately 70 x 25kg bags or 2 x 875kg bulk bags of ballast.

**How much ballast do i need for a shed base**

The amount of ballast and cement needed for a shed base depends on factors like the size of the shed and the cement to ballast mix ratio. As a general guideline, for a shed base, you’ll need something about 70 25kg of ballast and 14 25kg bags of cement per cubic meter of concrete

If your shed base is 1.8 meters long, 1.2 meters wide and 100 mm thick. Volume of slab = 1.8m × 1.2m × 0.1m = 0.216m3. So our estimate is 15 bags (25kg each) of ballast (since no. 25kg of ballast bags = 70× 0.216 = 15 bags) and 3 bags (25kg) of cement (since, no. of 25kg bags of cement = 14 × 0.216 = 3 bags).

**Conclusions:**

To determine how much ballast you need for your patio, slab, driveway and shed base: as a general guideline, you’ll need approximately 1,750 kg to 1,800 kg (or 2 bulk bags, or 70 x 25kg) of ballast and 8 x 50kg or 14 x 25kg bags of cement per cubic meter of concrete.