# Unit Weight of Building Materials Used In Construction

## What is Unit Weight?

Unit weight or specific weight of any material is its weight per unit volume that means in a unit volume, how much weight of the material can be placed.

Volume is measured in litres or cubic meters, and weight is expressed in kg or kilo Newton. Hence it is expressed in KN/m3 in the SI unit and KG/ m3 in the MKS unit system, and g/cc in the CGS unit system.

Unit or Specific Weight = Weight / Volume = W / V

## What is Density?

The density of any substance/material is its mass per unit volume, and it is expressed in  KG/ m3 or lb/m3. The symbol Rho (ρ) represents it.

Density describes the level of compactness of a substance. If the material has more density, that means it is more compact.

Density = Mass / Volume

ρ = M/V

## What is the difference Between Unit or Specific Weight and Density?

Unit weight of any substance is its weight per unit volume, while the density of any material is its mass per unit volume. Both terms can be used interchangeably.

To understand the difference between unit weight and the density first, we need to understand the difference between weight and mass.

Any substance or material on this planet or anywhere has some mass, and it can’t be zero, and it is measured in kg. M denotes it.

M = w/g

While weight is a force due to gravity acceleration and it is measured in newton. If there is no gravity acceleration, it may be zero. It is denoted by W.

W = m × g

Where g = acceleration due to gravity

I hope now you understood the difference between these two terms.

## Why is Unit Weight Important?

The unit weight is essential for weight calculation purposes. With the help of Unit Weight, we can calculate the weight of any material.

It also helps to determine the structure’s weight, which is designed to carry the specific load so that it remains intact and within limits.

Unit weight of any material also helps to calculate the quantity of material required for particular space.

The density of any material also decides whether it will sink or float on water. Suppose the substance density is less than water’s density.

In that case, it will float, and if the substance density is more than the water’s density, it will sink into the water.

## Unit Weight of MaterialsUsed In Construction

Here we are providing the unit weight of different building materials in alphabetical order for your convenience.

Conversion:

1 kN/m3 = 101.9716 kg/m3 say = 100 kg/m3 (round off)

1 kg/m3 = 0.0624 lb/ft3