Before concreting, workers should check the elevation of the subbase by:

Before concreting, workers should check the elevation of the subbase by:

• A. Measuring down from a straightedge spanning between the side forms.
• B. Using a laser level on the subbase
• C. Measuring from the top of the forms to the subbase
• D. Estimating elevation by eye

Answer: (A)

The main idea is to use a stable reference plane to confirm the subbase is at the correct elevation before pouring. A straightedge laid across the top of the side forms creates that plane across the width, so workers can measure from this straightedge down to the subbase at multiple points. This quick check reveals high or low spots in the subbase and allows for adjustments so the concrete will end up at the intended thickness and level. Laser levels can be used on some jobs, but the straightedge method is the traditional, dependable approach that directly ties the measurement to the formwork, ensuring consistency across the pour. Measuring from the top of the forms to the subbase incorporates the form thickness into the reading and can be inaccurate if forms aren’t perfectly level. Estimating by eye isn’t reliable for achieving a consistent, true grade.

The main idea is to use a stable reference plane to confirm the subbase is at the correct elevation before pouring. A straightedge laid across the top of the side forms creates that plane across the width, so workers can measure from this straightedge down to the subbase at multiple points. This quick check reveals high or low spots in the subbase and allows for adjustments so the concrete will end up at the intended thickness and level.

Laser levels can be used on some jobs, but the straightedge method is the traditional, dependable approach that directly ties the measurement to the formwork, ensuring consistency across the pour. Measuring from the top of the forms to the subbase incorporates the form thickness into the reading and can be inaccurate if forms aren’t perfectly level. Estimating by eye isn’t reliable for achieving a consistent, true grade.