6.3 Method applied and classification system 
Having examined the effectiveness for the Bangkok 
situation of each previously employed method to 
estimate the number of houses, it was decided to 
adopt a housing unit count technique complemented 
for some areas with a land use method. The enlarged 
SFAP at the scale of 1:15,000 gave sufficient 
resolution for counting individual dwelling units in 
most areas; where counting proved difficult, spatial 
characteristics associated with each residential 
land use were applied. For multi-storey buildings, 
which the previous findings confirmed to generate 
great error (Watkin, 1984), other more reliable 
sources of information, such as questionnaires or 
fieldchecks, were needed. 
A set of residential classifications was developed 
so that housing unit count could be carried out 
systematically. The classes should be used to deter 
mine how the condition of housing stock has changed 
over the last decade. Three main classes, private, 
public and informal, were applied, and those classes 
were further sub-divided into 10 types of housing 
projects. Through interpretation, and delineation of 
air photographs, data regarding residential area 
devoted to each subclass, were obtained. One might 
argue that it is not possible to identify private or 
public sectors, as such is not identifiable on air 
photographs; to a certain extent, information from 
other sources, and local knowledge, were applied. 
The majority of housing type classifications were, 
however, seen on aerial photographs. 
These 10 classes were further sub-divided by 
building types for counting the number of houses in 
each residential area unit (polygon). A detailed 
description of the residential classification is 
given below. 
6.4 Description of the classification 
1 PRIVATE FORMAL 
1.1 Shophouse project 
The floor plan of a shophouse is that of a 
rectangle. They occur in terraces of 8 to 20 units. 
The average unit size is 4 meters frontage by 12 
meters in depth. Construction is normally multi 
storey, from 2 to 4 storeys. The ground floor is 
used for commerical purposes and the upper floors 
are residential, often occupied by a single family. 
Shophouses are usually found bordering main and 
secondary roads, and are often grouped to form small 
commercial residential areas. 
1.2 Private housing projects (Developer build 
housing) 
These vary in form and type, consisting of 
detached dwellings, terraced houses or multi-storey 
apartments, and combinations of these types within 
the single development. Private housing projects are 
normally well-planned, and serviced by high standard 
access roads. House construction and design is 
normally uniform and of a high standard. 
1.3 Land sub-division project 
These consist of large tracts of land which have 
been planned and sub-divided into individual build 
ing plots, either with or without the provision of 
infrastructural services. A regular street pattern 
is a readily recognizable feature. Generally, dwel 
lings are individually designed detached houses, and 
are well-planned, but lay-outs differ from one 
dwelling to another. Construction is on piece-meal 
basis so a number of vacant plots between each house 
is generally found. 
1.4 Individual building 
These can comprise detached dwellings, small scale 
terrace developments, small scale shophouse 
developments; these are scattered throughout the 
city. 
2 PUBLIC FORMAL 
Public Housing projects: Housing projects built by 
National Housing Authority (NHA) and other govern 
ment agencies (i.e. non NHA). 
2.1 NHA project 
The NHA is responsible for constructing low income 
housing, which it does by building various forms of 
housing, including detached, semi-detached and 
terraced housing, four storey walk-up, and multi 
storey apartments including the provision of 
infrastructure. In addition to standard house 
building, the NHA also undertake sites & services 
housing schemes. 
2.2 Non NHA project 
Other government agencies also provide housing for 
their employees, under social welfare programmes. 
Various types of housing, including detached houses, 
terraced houses, and apartment blocks. 
(Information on the public sector was taken from 
other sources) 
3 INFORMAL SECTOR 
3.1 Slums and Squatter type settlement 
Areas with dense, small, irregular, owner-built 
temporary and semi-permanent dwellings. Access and 
services are limited, and the quality of materials 
is often poor, resulting in poor living conditions. 
3.2 Potential slums 
These areas demonstrate many of the same charac 
teristics as slums; however, their density is 
usually lower and dwelling sizes are larger; usually 
to be found on the fringe areas of the city. 
3.3 Mini-slum 
These have the same characteristics as slums but 
each area so defined is limited to 30 dwellings. 
Such settlements are scattered throughout the city 
and occupy in-fill sites. 
3.4 Klong Houses 
These are mainly traditional Thai-style houses 
situated on or near the banks of Klongs (Canals). 
They are characterized by having their principal 
access to the adjacent waterway and form ribbon 
developments to the waterway. In the inner city 
areas many such houses have degenerated into slums. 
4 OTHERS 
These are housing units which cannot be classified 
under any of the above categories and consist of 
structures used living though not necessarily for 
residential purpose; for example, out-buildings, 
such as servant quarters garages, sheds and all 
makeshift structures built to house construction 
workers. Some temples, high-rise slums, industrial 
dormitories, and boat houses fall into this 
category. 
The classification is subdivided into building 
type as follows: