Levels of gypsum plasterboard lining jointing

There are four specified and defined levels for jointing plasterboard surfaces Q1, Q2, Q3 and Q4. An appropriate gypsum board finish level is selected depending on the investor's requirements concerning the quality (degree of smoothness) of the surface, the intended use of the room and the method of finishing the surface (ceramic tiles, wallpaper, thin-coat paints etc.)

1. Levels of gypsum board finish PSG 1 [Quality Level 1 (Q1)] This mudding level refers to plasterboard surfaces in relation to which no aesthetic requirements have been formulated (e.g. a substrate for ceramic tiles). All that is required is the application of basic filler, which includes:

   • joint filling of plasterboard joints

   • coating filling visible parts of fixing and finishing elements. Mudding at this basic level assumes that at the plasterboard edges a reinforcing tape of glass fibre (self-adhesive mesh) is applied and mudded one or two layers of the system-included joint compound system-included joint compound

2. Level Mudding Gypsum Board PSG 2 [Quality Level 2 (Q2)] Mudding gypsum board plasterboard at this level is referred to as standard mudding and it meets the expectations usually applied to the aesthetic requirements for wall and ceiling surfaces. The aim of the work carried out by the drywall lining fitter at Gypsum Filler Level PSG 2 is to level and smooth the joint surface in such a way that it forms a single surface together with the plasterboard. This 'alignment' also applies to fasteners, internal and external corners and connections. fillering at PSG level 2 includes:

   • PSG 1 basic joiinting

   • repeated jointing with the system-included joint compounds: structure joint compound, when required, and finishing compound until a smooth transition of the joint surface to the plasterboard surface is achieved. It is not permissible to leave localised depressions and scratches from the tools used.

   • The surface thus prepared is then suitable for: covering with wallpaper, structural paints and typical matt paints, emulsions and acrylics applied with rollers or brushes, and covering with decorative plasters.

3. Level Filling Gypsum Board PSG 3 [Quality Level 3 (Q3)] In the event of heightened aesthetic demands on the surface of the mudded surfacesit is necessary to take additional measures going beyond mudding basic and standard mudding. Filling at PSG level 3 assumes:

   • filling standard PSG 2

   • mudding of the entire surface of a partition element (joints and cardboard) with system-included joint compound, muds or system-included smoothing compounds the aim of which is to even out the surface as well as close the micropores and uniform texture and absorption on these surfaces. The thickness of the layer applied is small and usually does not exceed 1 mm.
     
     The surface thus prepared is designed to:

   • coverings with fine-textured wallpaper;

   • silk and gloss paints

   • plasters with a grain size of less than 1 mm, provided that the manufacturer of the plaster authorises their use on the substrate in question.

4. Level Filling Gypsum Board PSG 4 [Quality Level 4 (Q4)] To meet the highest aesthetic requirements for mudded plasterboard surfaces plasterboards a thin layer of gypsum plaster is applied over the entire surface. Gypsum Filler Level PSG 4 involves the manual or mechanical application of a thin-coat plaster or special gypsum finish (layer thickness up to 3 mm) to the entire surface of the lining element. In addition to smoothing, it is often necessary to polish the entire layer applied. The surface thus prepared is suitable for covering with smooth or structured glossy wallcoverings, e.g. self-adhesive metal or vinyl films; covering with glossy paints, as well as obtaining polished alabaster gypsum surfaces imitating marble.