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I l luminat ion& Decorat ion
of F lat Sur faces
It must be appreciated that no building surface is perfectly flat and that the best that can be
expected is the appearance of flatness. Unfortunately, this appearance can easily be destroyed
by the effect of glancing light, whether natural or artificial. Illumination and Decoration of Flat
Surfaces shows the effect of different light sources on a variety of lining materials and paints
so that best results can be achieved.
Different types of building surfaces are investigated, including set plaster, fibrous plaster,
hardboard and gypsum board with gloss and semi-gloss paint applied. This full-colour
edition also discusses new building materials such as cement sheet, polystyrene and various
composite panels, as well as new building practices, low embodied energy materials and
higher energy efficiency of buildings.
Illumination and Decoration of Flat Surfaces is a must-have for people involved in the building
industry, both commercial and residential.
BoB Cameron
SIxTh eDITIon
BOB CAMERON
I l luminat ion& Decorat ion
of F lat Sur faces
SIXTH EDITION
Illumination TDesign.indd 1 6/3/09 10:31:52 AM
Published by
Landlinks Press
150 Oxford Street (PO Box 1139)
Collingwood VIC 3066
Australia
Telephone: +61 3 9662 7666
Local call: 1300 788 000 (Australia only)
Fax: +61 3 9662 7555
Email: [email protected]
Web site: www.landlinks.com
Landlinks Press is an imprint of CSIRO PUBLISHING
Front cover photo by iStockphoto
Back cover photo by Bob Cameron
Set in 9/14 Vectora
Cover and text design by James Kelly
Typeset by James Kelly
Printed in Australia by Metro Printing Pty Ltd
First published by CSIRO Division of Building Research as
Report No. L8, 1960 (ISBN 0 634 00299 5), reprinted 1978,
1981, 1984; then as Technical Report TR 90/1, 1990
(ISBN 0 643 05085X), reprinted 1992.
CSIRO PUBLISHING publishes and distributes scientific,
technical and health science books, magazines and journals
from Australia to a worldwide audience and conducts
these activities autonomously from the research activities
of the Commonwealth Scientific and Industrial Research
Organisation (CSIRO).
The views expressed in this publication are those of the
author(s) and do not necessarily represent those of, and
should not be attributed to, the publisher or CSIRO.
Photo credits: Keith Cochrane – pp. 2, 3; Bob Cameron –
pp. 4, 5; Brett Grimley, Ecolibrium Design – pp. vii, 19, 20;
Ken Waddington – pp. 6, 7, 8, 9, 10, 11, 12, 13, 14, 15
© CSIRO 2009
All rights reserved. Except under the conditions described in the Australian Copyright Act 1968 and subsequent
amendments, no part of this publication may be reproduced, stored in a retrieval system or transmitted in any
form or by any means, electronic, mechanical, photocopying, recording, duplicating or otherwise, without the
prior permission of the copyright owner. Contact Landlinks Press for all permission requests.
National Library of Australia Cataloguing-in-Publication entry
Cameron, Bob.
Illumination and decoration of flat surfaces / Bob Cameron.
6th ed.
9780643094901 (pbk.)
Bibliography.
Walls.
Coatings.
Interior lighting.
Lighting, Architectural and decorative.
729.28
Illumination TDesign.indd 2 6/3/09 10:31:52 AM
iv Preface
vii Abstract
ix Introduction
1 Glancing light on flat surfaces
17 Avoiding the effects of glancing light
19 Colour, lighting and energy efficiency
21 Plasterboard
23 External lightweight cladding
25 Gloss paint on flat surfaces
27 Recommendations
29 References and links
C O N T E N T S
Illumination TDesign.indd 3 6/3/09 10:31:52 AM
P R E F A C E
One of the first things a young plasterer is told by his older colleagues
and mentors is ‘the sun is our harshest critic’. In fact, it is not only
the sunlight but sidelight from any source that will show up even
the tiniest imperfection in hand-finished surfaces. This effect can be
further exacerbated by the use of gloss paints.
It was early in my plastering career, while applying a polymer bound
aggregate finish to the external walls of a unit development, when I
first encountered this phenomenon. Although this was a relatively new
technique at the time, the job had been progressing well and we had
been able to achieve what we thought was a very high standard of
finish. I was quite surprised when I received a frantic call from the site
foreman informing me that when the scaffold had been taken down
there were areas where the work was not up to standard. ‘Looks
like it has been thrown on with a shovel’, I believe were his exact
words. Incredulous that the walls we had so carefully finished with our
stainless steel trowels should attract such comments, I told him that
I would come down immediately and inspect the work myself. I was
then informed this would not be suitable for it was now mid-afternoon
and the walls were in the shade and apparently looked quite OK. I
met with the builder and architect on site the following morning at
precisely 10:15 am, when the sun would be throwing a glancing light
across the offending walls, to inspect the substandard workmanship
and propose a plan of action to rectify the situation. What followed
was a protracted series of site meetings and discussions between
architects, builders and tradesmen as well as experts of many
persuasions to finally arrive at the conclusion, so simply explained in
this book, that the work had been completed as well as practically
Page iv Illumination & decoration of flat surfaces
Illumination TDesign.indd 4 6/3/09 10:31:52 AM
possible. In the end no further action was taken and to the best of my
knowledge the walls have remained the same to this day.
It has been with great pleasure that I have undertaken the task of
updating this excellent and very useful publication. It is a superb
example of how the application of science can be of enduring
practical value to such an ancient trade as plastering and painting –
not by addressing the materials and processes themselves, but by
looking at the design and how these components are arranged to
achieve the desired outcome as economically as possible.
In updating the manuscript it has been important to retain the
simplicity of the original text and not overburden the book with
technical details. Instead we have included links to various websites
where this information can be found, in its most recent and up-to-
date form, or to other publications dealing with the specific topics.
Some of the changes that have occurred in the building industry
within Australia since the publication of the original edition include
the rise in the use of plasterboard and the almost complete
disappearance of fibrous plaster. Plasterboard has also replaced a lot
of hard-set plaster, although not to the same degree, and there is still
plenty of hard-set plaster used in some areas.
Significant changes have occurred in the external surfaces, with
rendered finishes becoming far more popular, making inroads into
the dominance of face brick and in some areas almost completely
replacing it. Greater awareness of energy efficiency has encouraged
the use of lightweight insulation systems, which also include a
rendered finish.
Page vPreface
Illumination TDesign.indd 5 6/3/09 10:31:52 AM
Illumination & decoration of flat surfacesPage vi
These trends, along with the continued push for higher quality
finishes at reduced costs, have greatly increased the need for this
new edition.
Part of the reason is the higher expectations from both the industry
and consumers, supported by a number of developments within the
industry. Modern building design and construction methods allow for
increasingly larger windows with fewer beams, pelmets and columns,
allowing light to enter the interior of the building almost parallel to the
wall and ceiling surfaces. Often these windows receive reflected light
from adjacent building surfaces or from water.
LEVELS OF FINISH
Australian/New Zealand Standard AS/NZS 2589:2007 defines
three levels of finish for plasterboard linings, covering the different
specifications for the framing, installation, finishing and decorating
required to achieve the various levels of finish. It is imperative that
the required level of finish is determined at the design stage of the
project with full consideration given to the lighting and decorative
finishes to be used.
Bob Cameron
Rockcote Enterprises Pty Ltd
Illumination TDesign.indd 6 6/3/09 10:31:52 AM
No building material has an absolutely flat surface; in practice, all that
may be expected is an appearance of flatness. This book reviews
the effect of glancing light on the appearance of flat surfaces of
hand-finished plaster, cement render and applied finishes, including
internal plaster finishes such as hard-set plaster, plasterboard and
fibrous plaster, as well as external surfaces such as cement render,
cement sheet and applied coatings. It shows that surfaces which
seem perfectly flat in diffuse light appear rough and uneven when lit
by light falling nearly parallel to the surface. The conclusion is drawn
that glancing light must be avoided if the appearance of flatness is
desired. Some practical ways of achieving this are discussed together
with the effects of gloss and semi-gloss paints on the appearance of
flat surfaces.
A B S T R A C T
Figure 1: The surface texture or imperfections that are not visible under diffuse light or where light of similar intensity strikes the surface at different angles (left), become obvious when light strikes the surface from one direction at an acute angle (right).
Page viiAbstract
Illumination TDesign.indd 7 6/3/09 10:31:53 AM
Illumination TDesign.indd 8 6/3/09 10:31:53 AM
Plain, flat surfaces are an important feature of building design. Flat,
unbroken surfaces free from distracting detail create an attractive,
spacious effect which is very popular in both commercial and
domestic buildings.
No hand-finished building material has a surface that is any better
than an approximation of flatness and this is true of all the common
lining and cladding materials used for large areas of unbroken
surfaces. To produce a surface approaching anything a physicist
would accept as flat would require the expenditure of thousands of
dollars on precision grinding, and therefore a building surface that is
perfectly flat is not practicable with present technology. In the building
industry the aim is to produce the appearance of flatness.
If the decorative effects of flat surfaces are desired, the true nature
of practical building surfaces must be considered when illumination
or use of paints is planned. Incorrect lighting or decoration can
completely destroy the illusion of flatness. The effects of glancing light
and gloss paint are examined in this book.
I N T R O D U C T I O N
Page ixIntroduction
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Illumination TDesign.indd 10 6/3/09 10:31:54 AM
It is economically impracticable to produce a building surface that is
flat in the literal sense of the word. Even slight deviations from true
flatness can cause light falling nearly parallel to the surface – for
example, glancing light or sidelighting – to cast shadows that are
irregular in shape and distribution. On a plain wall where there is no
pattern of irregularities to distract the eye, such shadows are very
noticeable and completely spoil the effect gained by elimination of
cover strips, V-joints and other ornamentation. They are most
noticeable when all the light comes from one direction and thus
there is no other illumination to dilute them.
Some striking examples of shadows cast by glancing light are shown
in Figures 2–6. Figure 2a shows the rendered wall of a building as it
appears under most conditions of natural lighting. Figure 2b shows
the same wall during the brief period when sunlight just skims the
surface, and here the wall presents a very different appearance
from that shown in Figure 2a. Shadows cast by differences in level
that were hardly noticeable in ordinary light give a rough, broken
impression and exaggerate the texture of the wall. Shadows are
cast by slight differences in level caused by the floating and
finishing of the surface.
G L A N C I N G L I G H T O N F L A T S U R F A C E S
Glancing light on flat surfaces Page 1
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Illumination & decoration of flat surfacesPage 2
Figure 2a: Rendered wall under standard daylight.
Fortunately the sun remains in this critical position for only a very short
period and its ability to reveal different textures in exterior surfaces
is not particularly important. This is not the case, however, when the
lighting of interior surfaces, especially artificial lighting, is considered.
Here the effect is not transient, as in the case shown in 2a and 2b,
but under unfavourable circumstances can be just as striking and the
effect is permanent while the unfavourable light is directed.
Illumination TDesign.indd 12 6/3/09 10:31:56 AM
Figure 2b: The same rendered wall as it appears when the sun’s rays are nearly parallel to the surface (glancing light).
Glancing light on flat surfaces Page 3
Illumination TDesign.indd 13 6/3/09 10:32:05 AM
Illumination & decoration of flat surfacesPage 4
Figure 3a: An area of a rendered wall as it appears by diffuse light.
Figures 3a and 3b further illustrate this point by showing another
example of a rendered wall under both standard and glancing
sunlight conditions, then showing the same wall illuminated by
glancing light from a wall light placed close to the surface in Figure
3c, which had just been painted with a sealer and two coats of matt
finish paint.
Illumination TDesign.indd 14 6/3/09 10:32:07 AM
Figure 3b: The same area of rendered wall as it appears in glancing sunlight.
Figure 3c: The same area of rendered wall showing the effects of a wall mounted light.
Glancing light on flat surfaces Page 5
Illumination TDesign.indd 15 6/3/09 10:32:12 AM
Illumination & decoration of flat surfacesPage 6
Figures 4a and 4b show the same area of set plaster identified
by a pair of drawing pins. In diffuse light the area seems quite flat
and featureless but this appearance is completely destroyed by
glancing light. Shadows and irregularities are now visible and it is
even possible to see the track of the trowel as it was moved over the
surface during polishing although the quality of workmanship was
high. These marks were invisible in diffused light.
Figure 4a: An area of hard-set plaster under standard lighting conditions.
Illumination TDesign.indd 16 6/3/09 10:32:24 AM
Figure 4b: The same area of hard-set plaster shown in Figure 4a as it appears by glancing light.
Glancing light on flat surfaces Page 7
Illumination TDesign.indd 17 6/3/09 10:32:38 AM
Illumination & decoration of flat surfacesPage 8
Figure 5a shows an area of flush-jointed fibrous plaster as
it appears by ordinary light. Figure 5b shows the same area
illuminated by glancing light, which has revealed minute
differences in level and the positions of the flush joint and
stoppings. The flush joint was of the highest workmanship and
could not be detected when a joint rule was run over the surface.
Figure 5a: An area of fibrous plaster as it appears by diffuse light.
Illumination TDesign.indd 18 6/3/09 10:32:53 AM
Figure 5b: The same area of fibrous plaster shown in Figure 5a as it appears by glancing light.
Glancing light on flat surfaces Page 9
Illumination TDesign.indd 19 6/3/09 10:33:07 AM
Illumination & decoration of flat surfacesPage 10
Figures 6a and 6b show an area of gypsum board by ordinary
light and by glancing light. Once again the illusion of flatness is
completely destroyed by shadows cast when the light is nearly
parallel to the surface.
Figure 6a: An area of plasterboard wall under normal lighting.
Illumination TDesign.indd 20 6/3/09 10:33:21 AM
Figure 6b: The same area under sidelight.
Glancing light on flat surfaces Page 11
Illumination TDesign.indd 21 6/3/09 10:33:36 AM
Illumination & decoration of flat surfacesPage 12
Figures 7a and 7b show the effects of ordinary and glancing light on
an area of hardboard containing a V-joint. The effects are similar to
those produced in the previous cases.
Figure 7a: An area of cement sheet containing a V-joint as it appears by diffuse light.
Illumination TDesign.indd 22 6/3/09 10:33:49 AM
Figure 7b: The same area of cement sheet shown in Figure 7a as it appears by glancing light.
Glancing light on flat surfaces Page 13
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Illumination & decoration of flat surfacesPage 14
Figure 8a is an example of a cement sheet wall with the joints taped
and set and a polymer render applied over the entire wall with the
objective of achieving an even rendered finish (Level 4). However, this
lightly textured sand finish shows up all the panel joints under the
severe sidelight of the early morning sun. This is a particularly good
example in that it is evident the builder has gone to considerable
effort to provide a flat surface by ensuring that the sheets run the full
length of the 3 m high wall, eliminating any horizontal joints.
Figure 8a: Cement sheet (Level 4) with the joints taped and set with an applied finish.
Illumination TDesign.indd 24 6/3/09 10:34:11 AM
Figure 8b shows the same wall a little later in the morning, a seamless
rendered finish with no imperfections evident under normal daylight.
The illustrations show the immense changes in appearance that
occur when illumination by glancing light is substituted for diffuse
light. The effects make it quite clear that if the appearance of flatness
is desired, it is necessary not only to have walls of good workmanship
but also to ensure that illumination is designed to avoid glancing light,
which can reveal the surface texture.
Figure 8b: The same wall area as Figure 8a under standard light.
Glancing light on flat surfaces Page 15
Illumination TDesign.indd 25 6/3/09 10:34:17 AM
Illumination TDesign.indd 26 6/3/09 10:34:17 AM
The worst effects are produced when a single unshaded lamp is
placed close to a wall or ceiling (as in Figure 3c), in an otherwise
darkened room or area. For example, the light cast by isolated,
unshaded fluorescent tubes fixed directly to the ceiling has particu-
larly severe effects on the appearance of adjoining surfaces. In this
case, putting the tube about 45 cm below the ceiling will ensure a
much better distribution of light and help make the irregularities in
the surface much less noticeable.
The problem is less acute in rooms lit by a number of more or less
evenly spaced units such as those used in large offices. Here, more
diffused light helps to dilute the texture-revealing shadows cast by
individual lamps, and surface irregularities will be less noticeable. Two
closely spaced rows of lamps will each negate the texture-revealing
shadows produced by the other in the area in between. In small
rooms, light reflected by the walls, particularly light-coloured walls,
produces a helpful diffused component in the lighting. Light-coloured
floors and furniture also help.
An alternative to suspending lamps below the level of the ceiling
is to put them above it, in recesses. Fluorescent tubes are ideal
for this treatment and attractive light recesses are available from
manufacturers of fibrous plaster. This treatment is quite satisfactory
in purely decorative interiors where a dark ceiling is required or
illumination of the ceiling doesn’t matter. However, in working interiors
such as those in factories, offices and schools, the health and
amenity for the worker must be considered and some loss in the
appearance of the surface may have to be accepted.
A V O I D I N G T H E E F F E C T S O F G L A N C I N G L I G H T
Page 17Avoiding the effects of glancing light
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Illumination & decoration of flat surfacesPage 18
Lamps mounted in recesses are liable to cause more glare than those
mounted on or below the ceiling and special precautions must be
taken to see that the ceiling is adequately illuminated by reflected
light or by other means, such as cornice lighting. Australian Standard
No. 1680: 1990 – Code of Practice for Interior Lighting and the Visual
Environment – recommends methods of controlling glare. It is most
important that these recommendations are observed in working
interiors, particularly where any form of recessed lighting is used.
Glancing light also occurs where windows extend to ceiling height or
are adjacent to walls, with the worst effects occurring when there are
narrow windows close to the walls. In these cases, suitable curtains or
pelmets will reduce the effects. The most useful light for the comfort
and efficiency of the worker is that entering at the top of the window
(the part nearest the ceiling), and it may be necessary for appearance
to take second place over other considerations. People tend to be
less aware of the appearance of overhead surfaces than those at eye
level and slight irregularities that would be obvious to a plasterer or an
architect will mostly go unnoticed by the average occupant.
Illumination TDesign.indd 28 6/3/09 10:34:17 AM
The benefits of natural light – using diffused daylight reflected off
light-coloured walls – can save energy while increasing the comfort
levels and amenity of the internal environment. This will also reduce
the effects of glancing light on the walls and ceilings. Paint is one of
our most effective lighting tools. Light-coloured matt paint or fine
textured finishes will diffuse and reflect both natural and artificial
light. Diffused light reflected from a number of directions will help
mask minor surface imperfections while creating a more
comfortable environment for the inhabitants. Direct light from a
single source, darker colours and gloss finishes will exacerbate
any surface imperfections.
C O L O U R , L I G H T I N G A N D E N E R G Y E F F I C I E N C Y
Figure 9: A surface mounted light fitting will cast a sidelight across the ceiling, highlighting even the smallest imperfections.
Page 19Colour, lighting and energy efficiency
Illumination TDesign.indd 29 6/3/09 10:34:18 AM
Illumination & decoration of flat surfacesPage 20
Figure 11: Align plasterboard joints parallel with wall lighting rather than across the light.
Figure 12: Align plasterboard joints parallel with light coming from a window rather than across the light.
Figure 10: Improved lighting design with the light fittings either recessed into the ceiling or suspended below with reflectors direct the light into the room rather than across the ceiling.
Illumination TDesign.indd 30 6/3/09 10:34:20 AM
While plasterboard has been finished the same way for many years,
modern buildings and consumer expectations require a high level of
finish. Plasterboard surfaces are of particular concern in respect to
the effects of glancing light. This is due to the nature of the materi-
als, standard industry practice and consumer expectations. The
plasterboard itself, being a machine-finished component, has a
much flatter surface than it is possible to achieve with the hand-
finished plaster joints. So even when the workmanship is of a very
high standard and well within tolerances set by industry bodies, the
wall surface can look very poor under glancing light with the
hand-finished plastered joints ruining the desired flat, even surface.
This method of finishing plasterboard, referred to as a Level 4 finish,
has always been the standard specification for almost all plaster-
board installations throughout Australia. However, this may no
longer be the most suitable system to meet the requirements of
modern buildings and consumer expectations in this country. It may
well be time for Australia to follow the lead of most other western
European countries and specify a higher standard of finish for our
plasterboard linings.
This would require agreement within the industry on exactly what a
Level 5 finish entails and the standard to be adopted by the industry.
Again drawing on overseas experience, the defining feature of the
Level 5 finish is the inclusion of a skim coat of plaster over the entire
wall area. Although such a skim coat is a hand-finished surface, the
imperfections are now overall rather than on joints and visible panels
providing a much more acceptable finished effect. Having an even
surface with the same surface texture and suction characteristics
removes the source of many of the problems currently associated
with the decoration and aesthetics of plasterboard linings.
P L A S T E R B O A R D
Page 21Plasterboard
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Illumination & decoration of flat surfacesPage 22
LEVEL OF FINISH CHARACTERISTICS AND FINISH
Levels 1–2 No longer in use.
Level 3
All joints, internal and external angles taped and set flush with the board surface.
Suitable for areas that do not require a decorative finish such as above the ceiling level, lift shafts etc.
Level 4
All joints taped, set flush and sanded smooth. Fixing heads set flush and sanded. External angles beaded, set flush and sanded.
Currently the default level of finish for plasterboard linings unless specified otherwise. Suitable for decoration with flat or low sheen paints.
Level 5
All joints and internal angles taped and set flush. Reinforcing angle beads fitted to external angles. Skim coat of plaster over entire wall.
Used in areas requiring the highest possible standard of finish. Provides a smooth, flat surface with even porosity and suction.
Table 1: Levels of finish for plasterboard linings
Table 1 outlines only the essential characteristics of the finishing
system for the respective levels of finish. For a description of the
complete system see AS/NZS 2589: 2007 Gypsum Linings –
Application and Finishing.
Illumination TDesign.indd 32 6/3/09 10:34:20 AM
Lightweight external cladding systems installed over timber and steel
frame walls have become increasingly popular. This trend was
initially driven by the fashion for rendered finishes and has gained
momentum in recent years with the call for more energy efficient
buildings and building materials.
These systems are based on either cement sheet, expanded
polystyrene, extruded polystyrene or various composite panels. There
are essentially two distinct methods of finishing these systems, each
capable of providing a different standard of finish (see Table 2).
Standard industry practice for finishing cement sheet walls with an
applied finish is to tape and set the joints, prime the wall and apply an
acrylic-based texture coating or polymer-based render. A competent
applicator using this procedure can only count on achieving a Level 4
finish. Under glancing light the panel joints may still be visible. In fact,
these cladding systems fare particularly badly under glancing light,
leading to many complaints from the industry and end users alike.
The problem is similar to the situation with plasterboard in that the
expectation, even from builders and architects, is that setting the
joints and applying 2–3 mm of texture coating should provide a Level
5 finish. The fact is that this is not a practical expectation using this
system, leading to a great deal of dissatisfaction and disputes within
the industry.
To achieve a higher level of finish over lightweight cladding
installations a screeded cement render is the preferred option.
This consists of a polymer modified cement render incorporating a
glass fibre reinforcing mesh. The render is applied to a thickness of
approximately 4–8 mm and the wall is screeded, helping to cover
E X T E R N A L L I G H T W E I G H T C L A D D I N G
Page 23External lightweight cladding
Illumination TDesign.indd 33 6/3/09 10:34:20 AM
Illumination & decoration of flat surfacesPage 24
any irregularities in the substrate. This process can provide the
look and feel of a rendered solid masonry wall over lightweight
insulation systems.
A Level 5 finish will still show the normal imperfections under
glancing light that could be expected from any other screeded
render finish; however, the panel joints should not be visible
under any lighting conditions.
Table 2: Levels of finish for lightweight cladding
LEVEL OF FINISH CHARACTERISTICS AND FINISH
Level 1
Expressed joints
Visible PVC sheet joiners
Painted flat finish
Will follow the frame straightness
Level 2
Joints taped and set
Roll-on finish
Joints hidden behind coatings system
Joints may show through under standard lighting conditions
Not suitable for quality broad wall installation
Level 3
Joints taped and set
+ 2 mm trowel-on texture coating or polymer render
Joints not visible under normal lighting conditions
Joints may be visible under sidelight conditions (critical light)
Not recommended for broad wall applications on quality projects
Level 4
Joints taped and set
Polymer render over entire wall
+ 2 mm trowel-on texture coating or polymer render
Joints not visible under normal lighting conditions
Joints may be visible under sidelight conditions (critical light)
Not recommended for broad wall applications on quality projects
Level 5
Screeded reinforced cement render
Minimum 1 mm acrylic-based texture coating or membrane paint
No visible joints under any light conditions
Look and feel of rendered masonry
Illumination TDesign.indd 34 6/3/09 10:34:20 AM
We have seen that badly designed lighting can spoil the appearance
of a flat surface and that similar effects may also occur when gloss
paints are used. Gloss paint reflects light so that a blurred mirror
image of the light source is formed which is distorted by irregularities
in the surface. The irregularities become particularly noticeable when
the observer moves in relation to the surface just like an image in an
uneven mirror changes in shape or size when observed from
different positions.
For this reason gloss paint should not be applied to flat walls which
may be observed from a wide angle, or to upper surfaces or the
ceiling on which tell-tale reflections of the lighting units may be seen.
Its use on ceilings and long walls may therefore be undesirable but it
can probably be applied to short walls with reasonably good results.
The same effects seen with gloss paints occur to a lesser degree
with satin- or silk-finish paints. High-gloss paints can safely be used
on doors, woodwork and architraves which have plenty of detail to
distract the eye from the distorted reflections.
It must be emphasised that these considerations apply only where
the effect of a flat, featureless surface is the main requirement.
There are circumstances in which gloss paints may be desirable for
functional reasons, for example in kitchens, bathrooms or laundries,
in which case some loss in appearance of the surfaces may have to
be accepted.
G L O S S P A I N T O N F L A T S U R F A C E S
Page 25Gloss paint on flat surfaces
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If the decorative effects of expanses of flat, unbroken surfaces are to
be appreciated it must be recognised when the lighting is planned
that no building surface is perfectly flat. The aim in building is to
produce the appearance of flatness and with practical surfaces the
appearance of flatness can always be destroyed by glancing light.
This is not a serious difficulty in offices and factories lit in accordance
with the principles outlined in Australian Standard No. 1680: 1990;
however, in domestic situations where the code does not apply,
isolated lamps are often used and the following points should be
especially considered.
Glancing light from isolated sources must be avoided. Where
isolated lamps are used, they are best placed well below the level
of the ceiling, or above it in suitably recessed light fittings. Care
must be taken when placing lights close to walls. In decorative
interiors, valances or ‘cafe curtains’ may be used on windows
that reach ceiling height and narrow windows close to walls
should be curtained.
High-gloss paint should be avoided whenever the surface can be
seen from a wide angle. This precludes its use on ceilings and long
walls if an even appearance is required.
If the effect of a flat, unbroken surface is desired the painting and
illumination must be planned accordingly. If this is not done and
unsightly effects are obtained one cannot justly blame the lights, the
lining material or the paint. It is the way in which these elements have
been combined that is at fault.
R E C O M M E N D A T I O N S
Page 27Recommendations
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It is beyond the scope of this book to fully explore the technical
details relating to the design, construction, lining, plastering,
decorating and lighting of buildings. Moreover, these technical
details can change over time. So we have included various links to
industry bodies and company websites where the latest information
and standards can be obtained. Also listed are reference books that
contain useful and relevant information on these topics.
LINKSAssociation of Wall and Ceiling Industries,
<http://www.awci.org.au>
Boral Limited, <http://www.boral.com.au>
CSR Building Products, <http://www.csr.com.au>
James Hardie, <http://www.jameshardie.com.au>
BGC, <http://www.bgc.com.au>
Rockcote, <http://www.rockcote.com.au> – this website contains
information on all exterior and interior surface preparation and
finishing systems.
R E F E R E N C E S A N D L I N K S
Page 29References and links
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Illumination & decoration of flat surfacesPage 30
REFERENCE BOOKSAustralian Standard (1990) AS 1680: 1990 Code of Practice for
Interior Lighting and the Visual Environment. Standards Australia,
Sydney.
Australian/New Zealand Standard (2007) AS/NZS 2589: 2007
Gypsum Linings – Application and Finishing. Standards Australia,
Sydney.
Phillips RO (1999) Sunlight and Shade in Australasia. Sixth edition.
CSIRO Publishing, Melbourne.
Lechner N (2008) Heating, Cooling, Lighting: Design Methods for
Architects. Third edition. Wiley, New Jersey.
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