The least overall average thickness of a web should not be less than 1 cm. And, least overall average thickness of a shell should be 2 cm.

Bricks and stones can be simultaneously used in three forms of composite masonry ? brick-backed ashlar masonry, brick-backed stone slab facing and rubble-backed brick masonry. Hence, stone-backed masonry is not a form of brick stone composite masonry.

There are various blocks used in concrete masonry. These are solid brick blocks, partition blocks, floor blocks, lintel blocks, corner blocks, etc. The solid brick blocks are most commonly used blocks.

In reinforced brick masonry, reinforcement can be laid both horizontally or vertically. In horizontal reinforcement, bars are placed in such a way that y go all way through wall while in vertical reinforcement, vertical steel bars are placed at all corners of walls.

Plumb rule is a tool that consists of a plumb line and a bob. It is extensively used by builders and surveyors for checking verticality of walls.

Common finished surface is obtained by mixing appropriate aggregates. Glazed finish is used to give a shiny appearance. Coloured finish is obtained by adding various colored pigments to concrete mix to impart different colors whereas in specially faced finish, finishing material such as marble, is used on facing side of block.

Composite stone masonry is a combination of ashlar masonry and rubble masonry. Rubble masonry is composed of irregular shaped stones, while ashlar masonry consists of regular shaped stones and gives a smooth and pleasant appearance. Hence, rubble masonry is used in backing of wall while ashlar masonry is used in facing.

The Concrete Association of India recommends that shape of cores in blocks used in concrete masonry should be oval. There should be at least two cores in blocks.

Composite masonry is one that is constructed out of two or more than two types of building units or in which different types of building materials are used for construction. It is of following types ? stone composite masonry, brick stone composite masonry, cement concrete masonry, hollow clay tile masonry, reinforced brick masonry and glass block masonry.

Concrete masonry uses two types of cement concrete blocks for construction of walls ? hollow concrete block and solid concrete block. A hollow concrete block has a core-void area greater than 25% of gross area.