The final appearance of painted interior wall and ceiling surfaces largely depends on the quality of the surface preparation, as well as the actual painting.  A well-prepared surface is one where the substrate is undamaged, hardened, dry, dusted and clean before painting. The levelling process is also relevant, which means filling any damages and cracks with the right mass for their size. This ensures the unevenness is levelled and the surface is suitably smooth for the chosen final coating.

Ready-to-use dispersion levelling compounds are usually used to level unevenness, cover cracks and smooth a surface. Their advantages include being easy to work with and offering enough time to allow application, smoothing and easy sanding. Appropriate consistency of the levelling compound is needed to ensure it does not run over the surface during application. It must also remain unchanged during normal manual application, when the levelling compound is mixed several times (removing excess mass from the wall and reapplying). It must also be easy to apply, stretch and sand. When spraying using a machine with a hopper, we recommend emptying the entirety of the levelling compound from the bucket into the hopper without additional work or cleaning.

Levelling compounds differ from each other mainly in the structure and particle size of the fillers, which also defines the maximum allowed application thicknesses. The interior levelling compounds SPEKTRA LEVEL ROUGHv, SPEKTRA LEVEL MEDIUM and SPEKTRA LEVEL FINE tick all these boxes.

SPEKTRA LEVEL ROUGH is a ready-to-use coarse levelling compound, intended for the first levelling of roughly plastered substrates and concrete. It fills the holes that form in the concrete as a result of pouring concrete on formwork surfaces; it does not run out and does not bubble. It is suitable for manual and machine application (devices with a worm pump are suitable) up to a maximum thickness of 6 mm in two coats. The smoothed surface does not need to be sanded. It is suitable for applying fine levelling compound.

SPEKTRA LEVEL MEDIUM is a medium-fine, ready-to-use levelling compound that allows application up to a maximum thickness of 4 mm in two coats. It is exceptionally easy to use and sand, and is suitable for the final smoothing of all types of interior wall and ceiling surfaces. Due to its high thixotropy, it does not dry out and is great for filling larger dents and cuts. It is suitable for manual and machine (airless) application.

SPEKTRA LEVEL FINE is a fine ready-to-use levelling compound that allows application up to a maximum thickness of 2 mm in two coats. Due to its exceptional smoothness, it is especially suitable for smoothing wall surfaces before applying semi-matt and glossy wall coatings and before executing decorative techniques that require a perfectly smooth base to achieve the desired aesthetic effect. It is suitable for manual and machine (airless) application, and is easy to use and sand.

Wall surfaces that are smoothed with SPEKTRA LEVEL MEDIUM or SPEKTRA LEVEL FINE can be applied with all types of dispersion paints, but we recommend them especially for high-quality coatings, which, with the use of appropriate tools (short pile rollers), stretch nicely and are distinguished by a very nice coverage. High-quality coatings tend to be less matte, so a smooth base is more important to prevent shadows or streaks due to an uneven surface.

As drywall constructions are increasingly common, dispersion interior levelling compounds are also used to level drywall elements such as gypsum plasterboard. The European Union of contractors of plastering, dry lining, stucco and related activities (UEEP) and Eurogypsum have created guidelines that define four levels of jointing and finishing gypsum board surfaces, from Q1-Q4. The Slovenian Association of Drywall Contractors has also adopted these guidelines; the quality levels are marked K1 - K4. Table 1 provides a brief summary of the requirements and characteristics for each level.

The examples given for the suitability of subsequent finish types and coverings in each of the quality levels should be considered as guidance only. The requirements regarding the level of treatment of gypsum plasterboard and type of finish application should be specified and agreed in the contract. The technical specifications for each material used must also be observed.

SPEKTRA LEVEL MEDIUM levelling compound can be used for levelling in Q2, when the gypsum wallboard joints are already made in Q1. It can also be used for levelling for gypsum wallboards in Q3 and is suitable for applying any matte interior wall paint. If choosing a high-quality interior wall paint for the finishing coating (e.g. SPEKTRA LATEX MATT or SPEKTRA LATEX SEMI-MATT) or ordering the execution of decorative techniques, which require the flattest and smoothest substrates possible, the required level of finishing is Q4. This is achieved either by combining a first layer of SPEKTRA LEVEL MEDIUM with a second layer of SPEKTRA LEVEL FINE or with SPEKTRA LEVEL FINE.

Table 1: Summary of requirements and characteristics of gypsum wallboard finishing levels