Concrete is measured by its strength capacity. MPa (megapascals) is the metric measurement for psi or pounds per square inch. The BC Building Codes require a minimum MPa for specific concrete projects. Please refer to the table to choose the appropriate MPa when calculating your volume and price.
|Footing, walls, foundations||15||0.70||n/a||20 – 25||0.55 – 0.60||3 – 5%|
|Interior flatwork||20||0.65||n/a||25 – 28||0.50 – 0.55||3 – 5%|
|Garages, carports||32||0.45||5 – 8%||32||0.45||5 – 6%|
|Exterior flatwork||32||0.45||5 – 8%||32||0.45||5 – 7%|
BCBC = BC Building Code 2006: Housing and Small Buildings
- Concrete is mixed with the correct “air-entrainment” (optimum air content). The following are some general guidelines.
- For garages, carports and any exterior flatwork that will be troweled, keep air in the low range – close to 5%. This will help reduce “crusting“ of the surface and blistering.
- For exterior flatwork that will not be troweled (broomed, exposed, etc.), keep air around 6% for freeze-thaw durability.
- For interior flatwork that will be troweled, keep air around 4%. This will help control bleeding and not cause blistering.