The Wall - Rebar, Concrete and Forms calculator computes the length or weight CONCRETE WALL Constructed wood forms Rebar Grid - One Mat of reinforcement bars (rebar), the volume of concrete, or the surface area of forms for a concrete wall.
INSTRUCTIONS: Choose length units (e.g. feet or meters) and enter the following:
Concrete Wall Materials: The calculator returns the rebar Length in feet, the rebar Weight in pounds, the Volume of concrete in cubic yards, and the Surface Area of the forms in square feet. However, all of these can be automatically converted to other units (e.g. feet to meters, pounds to kilograms, cubic yards to cubic meters, square feet to square meters) via the pull-down menu.
Note: The lapping portion of the rebar length calculation assumes that the uncut rebar on site is 40' (feet) in length and that lapping is not necessary under that length. Furthermore, this calculator assumes that rebar is lapped by a factor of 40 times the diameter of the rebar chosen. For the same calculations with the ability to add a different "uncut" length and/or a different lapping factor CLICK HERE.. The calculation determines the need for an extra rebar using an internal tolerance for for a spacing fraction that exceeds the tolerance with a default of 1". It also assumes that the uncut rebar is in 40' lengths and that lapping is needed for dimensions in excess of 40`. Furthermore, the lapping factor, when lapping is needed, is 40. For the same calculations with the ability to add a different "uncut" length and/or a different lapping factor CLICK HERE.
When the dimensions of your slab or wall exceed the length of a single piece of rebar, it is required to lap and tie the rebar to create the added length. There are a few considerations. First, the length of the lap is often specified as 40 times the diameter of the rebar. In this case, 40 is lapping factor. 60 is also a common factor, but the engineering specifications should always be applied. See these YouTube videos to better understand rebar lap:
Second, the typical length of pre-cut rebar is 40' and 60' in the United States.