Orangi Housing Primer

Introduction

Orangi, the largest katchi abadi of Pakistan, is spread over an area of 8,000 acres to the north—west of Karachi. Except for 1,300 acres, the rest of the area is illegally occupied by the 800,000 residents. These residents have procured land and services through the informal sector. The Informal Sector is a system of unauthorized developers who operate through political influence and official cooperation bought by the “dalals”.

Housing needs of the Orangi residents are also met by the informal sector. To facilitate construction of houses a network of “thallas” exists in Orangi. “Thallas” are building manufacturer’s yards which provide building materials technical advice and artisanal skills to the house builder. Materials of construction can be obtained either on cash or credit and sometimes cash loans are also extended to the builders. “Thallas” are therefore, of crucial importance in the house building process in Orangi.

Purpose of This Study

Orangi Pilot Project (OPP) plans to carry out a housing programme in Orangi to assist people in the building of houses. In order to do this effectively research was required into the existing state of affairs. To determine the areas of problem and seats of change, a study of the present housing situation, in Orangi, was designed by OPP consultants and supervised by OPP staff. It was carried out by the students of Dawood College of Engineering & Technology (DCET), Karachi. This report is a precise and reorganization of the original study.

House Type

There are basically three types of houses in Orangi Township. They are as follows:

1. Kutcha Houses
2. Semi-Pucca Houses
3. Pucca Houses

I. Kutcha Houses

1. Description

Kutcha houses are made of materials which are impermanent in nature and highly susceptible to forces of nature. The materials of construction are usually reed matts and industrial waste materials. The nature of these dwellings is temporary and with the inflow of cash most of the owners construct semi-pucca or pucca houses and regard these structures as a transitory stage.
The construction of kutcha houses can be described by their structural components as follows:

1.1 Foundations

In kutcha houses there are basically two, kinds of foundations:

• Stone Foundation.
• Mud Foundation.

1.1.1 Stone Foundation

Stone used in the construction of foundations in Orangi is quarried from the hills surrounding the township. The most common manner of construction is random rubble masonry. Occasionally coursed masonry is also used. The depth of the foundations vary from 8” to l’-0”. No bonding material is used to stabilize the foundation stones. (See photograph – 1).

1.1.2 Mud Foundation

The mud foundations of kutcha houses are usually raised 3’ above the ground level, without excavating the ground, to hold and stabilize the matt walls (See photograph 2 & 3). The mud construction is extremely unstable and easily eroded by water, sulphates in the soil, and other climatic effects. Constant plastering and maintenance is required.

1.2 Walls

Kutcha houses are usually made of matt walls. The reed mats are tied to a wooden frame of scrap timber columns spaced far apart. (See photograph – 4). Polythene and paper bags are also used in the construction of walls in addition to or as a substitute for mats. (See photograph – 5).

1.3 Roofing

The two most common kinds of roofing material used are reed mats and corrugated galvanized iron sheets. The reed mats are tied to a weak wooden truss made of scrap pieces of timber attached to the columns and are sloped to facilitate the drainage of rainwater since leakage is a problem due to the nature of the material (See photograph – 6). The corrugated galvanized iron roofs are placed over a timber frame and held down by concrete blocks. (See photograph – 7 & 8).

1.4 Openings

Except for the door there is little need of formal openings in kutcha houses since the openings in the materials and or their joints provide sufficient ventilation. If necessary, holes are cut in the matt/paper walls to serve as windows. (See photograph – 9).

1.5 Flooring

Floors are usually of compacted earth and require periodic maintenance. They are usually covered with mats.

2. Socio-Economic Background of The Owners

Owners of the kutcha houses come from the poorest strata of the society. They do not have enough resources to construct a house of a more permanent nature. As soon as the owner acquires enough money he seeks to build a pucca or semi-pucca house. The investment made in the structure is also meager, indicative of the final intentions of the owner. It is therefore unnecessary to propose strategies to improve the construction of kutcha houses.

3. Construction Process

Kutcha houses are built by the owner’s themselves. Five to 7% of the houses in Orangi are self made without any help from skilled or unskilled labour. Material is procured by the owners and house constructed within 2 or 4 days. The cost of these houses is anywhere between Rs 2,000 – Rs 4,000. Most of these houses have one or two rooms depending upon the needs and resources of the family.

3.1 Problems in Construction

The construction of “kutcha houses” is technically unsound. The stone foundations have no bonding material to provide stability. The settlement of un-bonded stones also causes cracks in walls if they are made of mud or stone. The material of the walls, whether mats or other industrial waste, is not tied to the structure properly and therefore collapses at the slightest wind pressure. (See photograph-b). The roofs of these houses leak profusely and are easily blown away by strong winds. The owners are aware of these problems but economic constraints prevent them from improving their homes.

II. Semi-Pucca Houses

1. Description

Semi-pucca houses are made of materials which are fairly resistant to the climatic forces and permanent in nature. It is their method of construction which renders them weak and susceptible to the forces of nature.
There are basically two kinds of semi-pucca houses in Orangi:

• Houses made of stone
• Houses made of wood

The two kinds of houses can be described by their structural components as follows

1.1 Stone Houses

1.1.1 Foundation:

The most common way of constructing a stone foundation in a “semi-pucca house” is to dig a ditch 2½’ deep and 1’ to 1½’ wide. This ditch is firmly filled with stones over which the wall is constructed. Bonding material between the stones is seldom used so as to save on costs.

The digging of a ditch is only possible where the ground is soft enough for easy excavation. In rocky areas where the ground is hard, a stone foundation is not used and the walls are erected directly off the ground. (See photograph – 11).

1.1.2 Walls

Stone used in the construction of the walls is similar to the one used in foundation. The stones are held together either by mud or mortar, depending on the resources of the builder. In a lot of cases no bonding material is used and the gaps in the stone work are hammer packed with smaller stones. (See photograph – 12). Labour for this form of construction is provided by the Pathan immigrants who have a tradition of building in stone.

1.1.3 Roofing

Roofing of stone houses is usually of:

• Galvanized iron or asbestos sheets
• Reed mats (chatai) / industrial waste

G.I. Sheets/Asbestos Sheets:
This is the most commonly used material for roofing in Orangi. These sheets are supported by wooden beams in stone houses and the sheets are overlapped 3” – 6” at each end. The wooden beams are supported on load bearing walls. The sheets are held in place concrete blocks along the perimeter of the structure. (See photograph – 13).

Reed Matts (Chatai) / Industrial Waste:
The reed mats are tied to a simple wooden structure which comprises of a central ridge beam and widely spaced wooden rafters. Other industrial waste material such as used cement bags is also used in a similar manner.

1.1.4 Openings

The openings in the walls of the stone houses are of considerable variety depending upon the economic resources of the residents. The most common kind of steel doors and windows, concrete “jallis” / (lattice work) and at times have no shutter at all. (See photograph – 14).

1.1.5 Flooring

Flooring in stone houses is either of mud plaster or the ground is left unpaved. The former is periodically maintained while the latter is usually covered by mats.

1.2 Wooden Houses

The wooden houses are built of unsized scrap wood as standarized timber is expensive. This manner of construction is usually carried out by the Baluch inhabitants of Orangi who have a long tradition of building in this manner. Different components of wooden houses are described blow

1.2.1 Foundations

The foundations of a wooden house are made of stone, placed above the ground. No bonding material is used to hold the stones together. (See photograph 15 & 16).

1.2.2 Walls

The skeleton of the house consists of a bare minimum number of supports. Wooden columns are placed far apart along the four sides of the structure which in turn support the roof truss. (See photograph 17 & 18). Wall in full to the skeleton consist of scrap pieces of wood, joined together at the lower part of each strip where they overlap and nailed to the intermittent columns. (See photograph 19 & 20).

1.2.3 Roofing

The most common material used in roofing of the wooden houses is reed matts or ‘chatai’. In some cases terra cotta tiles from old buildings are also used. (See photograph 21 & 22). The roof structure consists of a central wooden ridge beam supported by two columns at the far ends. The beam, along with widely spaced rafters bear, the weight of the roofing material. (See photograph 23). This is, however, seldom strong enough to take the weight of the terra cotta tiles and it is not unusual in such cases for the roof to sag. (See photograph 24).

1.2.4 Openings

The shutters to openings in the wooden houses are made of wood. In most cases however the openings are left unframed. The door openings have timber frames. (See photograph 25).

1.2.5 Flooring

The floors of wooden houses are usually plastered with mud and kept very clean.

2. Socio-Economic Conditions of The Owner’s of Semi-Pucca Houses

Owners of semi-pucca houses are usually poor and mostly comprise unskilled workers. Their average income is between Rs 800 to Rs 1,000, with a family size of at least six. The reason given for, choosing either stone or wood as, their medium of construction was economic constraint. Most of the stone houses are located at the foot hills of Orangi where stone is easily available and are self made. Thus not only the cost of labour is saved but also the cost of material, which is obtained free by the family from the hills over a period of time. The wooden houses are mostly owned by Baluchis, who are also located in the hilly areas. This form of construction is familiar to the residents and is mostly done by “mistris” (builders).