Garage Floor Concrete Calculator
About Garage Floor Concrete Calculator
Garage Floor Concrete Calculator works out the slab volume for a single or double garage floor. A single garage of 6 m x 3 m at 125 mm thick needs 2.25 m3, or 2.48 m3 with a 10 percent waste allowance. A double garage of 6 m x 6 m at the same thickness needs 4.5 m3, rising to 4.95 m3 with waste, which is a full ready mix delivery rather than a bag job. In imperial, a 20 ft x 20 ft garage at 5 inches thick comes to about 6.8 cubic yards with waste. Garage floors carry parked vehicle loads plus point loads from jacks, stands and storage racking, so 125 to 150 mm (5 to 6 inches) is normal and 100 mm is not enough. Because these volumes always exceed the practical bag mixing limit, the useful output here is the cubic metre or cubic yard figure you give the ready mix supplier. Order slightly over rather than under: a part load surcharge on a second delivery costs far more than the extra concrete in the first one.
How to use Garage Floor Concrete Calculator
- Choose metric or imperial input
- Enter length, width, and depth of your slab
- See volume and bag count in both metric and imperial instantly
Frequently Asked Questions
- How much concrete does a garage floor need?
- Multiply garage length by width by slab thickness. A 6 m x 3 m single garage at 125 mm needs 2.25 m3, or 2.48 m3 with waste. A 6 m x 6 m double garage at 125 mm needs 4.5 m3, or 4.95 m3 with waste, which is a full ready mix load.
- How thick should a garage floor slab be?
- One hundred and twenty five to 150 mm (5 to 6 inches) over a compacted sub base for normal car use. Go to 200 mm with reinforcement if the garage will hold a vehicle lift, heavy machinery or commercial vehicles.
- Should I use ready mix for a garage floor?
- Yes. Even a single garage floor is over 2 m3, which is more than 180 bags of 25 kg mix. A garage floor also needs to be poured and levelled in one continuous session to get a flat, joint free finish, which bag mixing cannot keep pace with.
- Does a garage floor need a fall to the door?
- A slight fall of around 1 in 100 toward the door helps water from a wet car drain out instead of pooling. The extra thickness at the high end is small and is covered by the standard waste allowance.
- Does the calculator account for the thickened edge?
- No. If the slab is designed with a thickened perimeter edge or an integral footing, calculate that edge separately as a footing run and add it to the floor volume before ordering.
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