Scaffolding is a temporary rigid structure made of still, bamboo or timber. The primary aim of constructing a scaffold is to create a platform on which mason can work at different heights. Scaffolds also help to lift materials for the immediate uses at different heights.
Common Types of Scaffolding
The following 4 types of scaffolding are commonly used in building construction work.
Brick layer’s Scaffolding or Single Scaffolding
Mason’s Scaffolding or Double Scaffolding
Steel or Tubular Scaffolding
Needle Scaffolding or Cantilever Scaffolding
1. Single Scaffolding / Brick Layer’s Scaffolding
In this type of scaffolding, a series of vertical members made of bamboo or timber (named as Standards), are firmly fixed into the ground in a row parallel to the building wall. The distance in between two standards is generally kept within 2.4 to 3 m.
These standards are connected to each by a longitudinal horizontal member (named as Ledgers). Ledgers are tied with standards at every rise of 120 cm to150 cm (i.e. 4 ft to 5 ft). Rope lashing is used to tie the standard with ledgers.
The putlogs (or transverse horizontal members) are placed at a horizontal spacing of 120 cm such that one end is supported on the ledgers and the other end is held in the holes made in the wall. Rope lashing is used to fasten the putlogs with ledgers.
If the height of the scaffolding is very high, to maintain its stability, sometimes diagonal members (named as Braces) are provided. Braces are cross diagonally fitted with the standards using rope lashing.
2. Double Scaffolding / Mason’s Scaffolding
This type of scaffolding is commonly used in case of stone masonry. It is stronger than brick layer’s scaffolding.
The primary differences between brick layer’s scaffolding and mason’s scaffolding are as follow:
In case of brick layer’s scaffolding single row of standard is fixed into the ground. But in case of mason’s scaffolding two rows of standards are fixed into the ground. First row of standards is fixed close to the wall and second row of standard is fixed at a distance of 1.5 m from the first row. This is why it is named as double scaffolding.
In case of brick layer’s scaffolding one end of putlog is fixed with wall. But in double scaffolding, putlogs are not fixed with the wall. Put logs are supported at both ends on ledgers. Therefore mason’s scaffolding is completely independent of the wall surface. And there is no need to make any hole on the wall surface.
Sometime raking shores are provided to prevent the slipping of scaffolding away from the wall.
3. Steel or Tubular Scaffolding
The method of construction of steel scaffolding is similar to that of brick layer’s and mason’s scaffolding. The primary differences are
Instead of using timber, steel tube of diameter of 40 m to 60 mm are used
Instead of using rope lashing, special types of steel couples are used for fastening
Instead of fixing the standards into the ground, it is placed on base plate
The gap between two standards in a row is generally kept within 2.5 m to 3 m. These standards are fixed on a square or round steel plate (known as Base Plate) by means of welding.
Ledgers are spaced at every rise of 1.8 m. Length of the putlogs are normally 1.2 m to 1.8m.
Advantages of the Steel Scaffolds are as follow:
It can be erected or dismantled more rapidly in comparison to timber scaffolding. This helps in saving construction time.
It is more durable than timber. Therefore it is economical in long run.
It has more fire resisting capacity
It is more suitable and safe to work at any height.
4. Needle Scaffolding / Cantilever Scaffolding
Needle scaffolding or cantilever scaffolding is required in the following cases
When it is not possible to fix standard into the ground
When construction is done on the side of a busy street
When construction work is carried out at very high level in case of tall building
In this type of scaffolding instead of fixing the standard into the ground, it is placed at some height above the ground level. The platform on which stands are placed is called needle. A needle is a cantilever structure, made of timber, projected out from the holes in wall.
To prevent lifting up of the needle, the inside end of the needles are supported by struts wedged between the needles and the head pieces.
The projected outward end of the needle is supported by an inclined strut which rests on the window sill.
The joints between the inclined strut and the needle are clamped by means of dogs.