How to Calculate How Much Concrete to Pour in a Lintel

Concrete beams spanning gaps in a wall are called lintels.

Whenever you want to span an opening in a wall, for example, for a window or door, you have to build a header, which is a beam that goes across the gap and supports the weight that the wall would have held. When you're building with concrete, the header beam is called a lintel. You'll need a concrete form of the appropriate size to pour the concrete for the lintel before hoisting it into place.

Things You'll Need

• Measuring tape

Instructions

1. Measure the length, width and height of the lintel form you'll pour the concrete into. For example, you may be spanning a 4-foot window and need an extra 1 foot on either side of the opening, which would be 6 feet long. The wall may be 6 inches wide, and the space could be 1 foot tall.

2. Multiply the width times the length and height (6 feet times 1 foot times 1/2 foot is 3 cubic feet).

3. Divide your answer from Step 2 by 2/3, since one 80-lb. bag of concrete fills two-thirds of a cubic foot (3 cubic feet divided by 2/3 is four-and-a-half bags of concrete).

Tips & Warnings

• Check the packaging on your ready-mix concrete to be sure it really fills two-thirds of a cubic foot per bag. Some specialty concretes have different volumes and come in sizes other than 80 lbs.

References

• University of Pittsburgh: Glossary of Medieval Art and Architecture - Lintel