Illumination and Decoration of Flat Surfaces

Bob Cameron

• Publisher: Landlinks Press
• Year: 2009
• Print ISBN: 9780643094901
• eBook ISBN: 9780643099111
• Edition: 6
• Topic: Technology & Engineering
• Subtopic: Architecture General
• Index: Technology & Engineering

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.

EXTERNAL LIGHTWEIGHT CLADDING

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 any irregularities in the substrate. This process can provide the look and feel of a rendered solid masonry wall over lightweight insulation systems.

Table 2: Levels of finish for lightweight cladding

LEVEL OF FINISH	CHARACTERISTICS AND FINISH
Level 1	Visible PVC sheet joiners
Expressed joints	Painted flat finish
	Will follow the frame straightness
Level 2	Joints hidden behind coatings system
Joints taped and set	Joints may show through under standard lighting
Roll-on finish	conditions
	Not suitable for quality broad wall installation
Level 3	Joints not visible under normal lighting conditions
Joints taped and set	Joints may be visible under sidelight conditions
+ 2 mm trowel-on texture coating or polymer render	(critical light)
	Not recommended for broad wall applications on
	quality projects
Level 4	Joints not visible under normal lighting conditions
Joints taped and set	Joints may be visible under sidelight conditions
Polymer render over entire wall	(critical light)
+ 2 mm trowel-on texture coating or polymer render	Not recommended for broad wall applications on
	quality projects
Level 5	No visible joints under any light conditions
Screeded reinforced cement render	Look and feel of rendered masonry
Minimum 1 mm acrylic-based texture coating or
membrane paint

A Level 5 finish will still show the normal imperfections under glancing light that could be expected from any o...

Table of contents

• Cover
• Title
• Copyright
• Contents
• Preface
• Abstract
• Introduction
• Glancing light on flat surfaces
• Avoiding the effects of glancing light
• Colour, lighting and energy efficiency
• Plasterboard
• External lightweight cladding
• Glass paint on flat surfaces
• Recommendations
• Refferences and links