# Wall - Rebar, Concrete and Forms

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vCalc.Wall - Rebar, Concrete and Forms
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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 your preferred length units (e.g. feet or meters) and enter the following:

• (L) This is the length of the wall.
• (H) This is the height of the wall.
• (W) This is the width or thickness of the wall.
• (rS) This is the rebar size.
• (oC) This is the rebar on-center spacing. (Default 18")
• (i) This is the rebar inset from the edges (Default 3")
• (M) This is the number of mats (grids)
• (Output)  This dictates the results shown by the calculator:
• Length of Rebar in the wall
• Weight of Rebar in the wall
• Volume of Concrete in the wall
• Forms Area of the concrete wall forms.  This is the amount of plywood or OSB needed to construct the forms.

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.

Related Calculators:

• Para calcular en el idioma español de vCalc, HAGA CLIC AQUÍ.
• To compute the amount of materials (plywood or OSB) needed for the forms in a concrete wall, CLICK HERE.
• See the Rebar Calculator for more concrete and rebar functions and features.

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.

Rebar Specifications

### Lapping

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.