There will be occasions when the standard plasterboard finish may not produce the most appropriate result. This may reflect choice on the part of the client or specifier, or may be additional treatment to counteract specific problems on a particular job - such as critical lighting.

Smooth Finishes

The normal trade standard for plasterboard in finished domestic and commercial application is a level 4 finish. Because the final surface is composed of areas of paper faced board jointed by sections of sanded stopping/setting compound, the finished surface is composed of surfaces which differ in texture, porosity and (minutely) level.

Even with best painting practices, some circumstances will allow apparent variations in the surface quality.

• Application of gloss paints

• Critical or reflected lighting (natural or artificial)

Skim Coating

In some states and New Zealand, it is recognised practice to skim coat the surface with a thin coat of compound. This is skilled and specialised work. Clearly, skim coating involves additional cost but can provide a level 5 finish where it is available.

Surface Modifiers/Filled Sealers

There is a small range of surface treatments which combined some of the characteristics of a very thin skim coating with the ease of application of a paint. These are essentially paint carriers with a gypsum filler. Some are sandable - some are not. Your local distributor of plaster products can advise you on available products and their capabilities and limitations.

In general, they offer an ability to present the painter with a uniform surface texture but may require multiple coats to even out small variations in level. They provide an improved level 4 finish but may not aspire to a full level 5.

Texture Coatings

In circumstances where critical or reflected lighting may be particularly intense, it is worth considering a texture coating system in which the texture obscures minor variations in surface quality. Texture coatings have an aesthetic appeal of their own and can of course be specified purely for their visual effect.

Texture coatings fall into three broad categories:

Paint TexturesThese are specially formulated coatings applied by the painter which are worked or stippled to produce a light textured finish. Generally, paint textures have a relative low relief, but can be most successful in offering a finish which is both different and tolerant of minor surface irregularities.

Manual Plaster Textures Many plasterers offer simple manually applied texture coatings based on skimming the surface with a plaster compound, then working the material to a texture finish - often with a broom or a mop.

These surface treatments offer a high relief and can be applied over a level 3 plasterboard finish. The selection of an appropriate texture is best made on the basis of an agreed sample.

Spray Plaster Textures - Texture coatings applied by spray fall into two categories:

1. Plaster compounds which when sprayed on the surface form a texture of plaster dimples or droplets.

2. Compounds which contain an aggregate - usually polystyrene or vermiculite which provides the raised portions of the texture.

The equipment used to apply these is sophisticated and capable of varying the texture from fine to coarse. The texture can be further modified on the wall or ceiling surface by knocking down with a trowel.

Local enquiries will have to be made regarding availability of this technique.

Aggreagate Coatings

have been around for some time and are popular for application to concrete soffites in high density housing. They are rarely used on plasterboard though entirely compatible.

Special Decorative Finishes - Artexing There are a few UK trained Artexers in the community who offer special decorative treatments which are highly individualistic. Your local Association of Wall and Ceiling Contractors can advise on local talent.