Table of Contents
In this article, we will discuss random rubble masonry and its 2 types.
The art of construction of stone units bonded together with mortar is called stone masonry. The stone masonry in which undressed or roughly dressed stones are utilized is called Rubble Masonry.
Masonry constructed using undressed or partially dressed stones in a random order is called Random Rubble Masonry.
Types of Random Rubble Masonry
There are 2- types of random rubble masonry:
1. Uncoursed Random Rubble Masonry
This is the roughest and cheapest form of stone-walling.
✔ In this type of masonry, the stones used are of widely different sizes.
✔ Since the stones are not of uniform size and shape; greater care and integrity have to be exercised in arranging them in such a way that they adequately distribute the pressure over the maximum area, and at the same time, long continuous vertical joints are avoided.
✔ Sound bond should be available both transversely as well as longitudinally. A transverse bond is obtained by the liberal use of headers.
✔ Larger stones are selected for quoins and jambs to give increased strength and a better appearance. This type of masonry is also known as uncoursed rubble masonry.
Some of the features of Uncoursed Random Rubble Masonry are:
a. It is the cheapest and roughest type of masonry.
b. It has a varying appearance.
c. Corners of stones are slightly knocked off before using.
d. To increase the strength of this masonry, large stones are used at corners and jambs.
e. “Through stone” is used in every square meter for joining faces and backing.
2. Built to Courses: Random Rubble Masonry
The method of construction is the same as above except that the work is roughly leveled up to form courses varying from 30 to 45 cm thick.
✔ All the courses are not of the same height.
✔ For the construction of this type of masonry, quoins are built first and a line (string) is stretched between the tops of quoins.
✔ The intervening walling is then brought up to this level by using different sizes of stones.
✔ The figure below shows the procedure, in which the stone has been numbered in the order in which they are placed. This form of masonry is better than uncoursed random rubble masonry.
Read Also: Artificial Stones
