Working Drawings Handbook
metre of concrete, he needs to know certain informa-
tion about its nature and physical dimensions.
2 He needs to know whereit is to be placed. This
demands pictorial and dimensional information
regarding its relationship to the building as a whole.
3 He needs to know howit is to be placed or fixed in
relation to its immediate neighbouring elements.
Clearly, these three questions—what, whereand how—
are fundamental to the business of building
communications, and demand a variety of replies in
practice if they are to be answered satisfactorily and
without ambiguity. It may be useful to reflect for a
moment on the degree of depth and comprehensiveness
that may be required of these answers.
If the designer has devised a precise solution to the
building problem set him by his client, then the
information to be conveyed to the builder must be of
sufficient detail to enable the unique nature of that
solution to be appreciated and converted into physical
building terms by a variety of people, most of whom will
be unfamiliar with the original problem and unaware of
the chain of thought processes which has given rise to
its solution.
So if we are dealing with a window, the single question—
What window?—may proliferate into a large and varied
series: what are its overall dimensions; what does it look
like; what material is it made from; what is its glass
thickness; what furniture does it have; what are its
finishes? These and many other questions will arise
from consideration of the nature of a single component.
Similarly we need to know where in the building it is to
be installed, implying the need for dimensional
information in three planes; and how it is to be
installed—how it sits in relation to the lintel above it, how
it relates to the vertical DPCs in the adjacent wall
cavities, how many fixing points are required and what is
the nature of their fixing. And so on.
The amount of information required so that the description
of any aspect of the building will be unambiguous must
always be a matter for intelligent consideration. The
strength and density of bricks forming footings below
ground level, for instance, will be fit subjects for precise
description, whereas their colour will not.But two fundamental principles emerge which will be
found to hold good at all times.1 All building information may be classified into three
basic categories, depending upon which of the three
basic questions—how, where and what—it purports to
answer.
2 All building information is hierarchic in its nature and
proceeds from the general to the particular.This latter observation requires some discussion,
because the sequence in which the three questions
which were posed at the start of this section emerge
may suggest that the seeker after information starts with
the component and its nature and then works outwards
to a consideration of where and how to install it. This
sequence is in fact occasionally true—the window
manufacturer, for example, would tend to consider the
type of window he was being called upon to make
before determining how many of them were in the
building and how they were distributed throughout it.But in general terms the reverse is true. Almost every user
of the information package will wish to know that there is a
wall of finite dimensions with windows in it which forms the
outer boundary of the building, before seeking to
determine the various forms that the windows might take
or the precise nature of the bricks and their pointing.Since this is also the manner in which the designer will
logically work, there is little difficulty, and every
advantage, in devising a system in which the search for
information starts with the question Where? The answer
to this question indicates where the answers may be
found to the supplementary questions What? and How?