Kerakoll Biogesso Rasa&Decora mangiaVOC skim coat and decorative plaster

Is the skimmed wall striped and patchy under grazing light? Filler that sets too quickly leaves no time for smoothing. Overlaps and edges remain. This filler has a long working time and withstands the grazing-light test. It does not even need to be painted for a decorative wall: two coats create a mirror-gloss, elegant white surface. As an exposed finish, it also absorbs formaldehyde. This is Kerakoll Biogesso Rasa&Decora mangiaVOC.

• Striped, patchy filler under grazing light: longer working time - even smoothing without overlaps, withstands the grazing-light test
• Patch-repaired, mixed substrate: two perpendicular skim-coat layers create a uniform plaster coat - a flat, smooth base for the special topcoat
• Occupied home, renovation: 90% less dust during mixing than conventional products - a cleaner work area, gentler on the applicator
• Formaldehyde in living spaces: the mangiaVOC effect captures formaldehyde and converts it into a neutral (inert) compound - the wall actively improves indoor air quality (Eurofins report)
• Decorative wall without painting: elegant white, warm-toned exposed finish - a glossy mirror effect in two coats, faux-marble effect with a short trowel
• Unique antique effect: can be mixed with linseed oil and natural coloured earth pigments - evoking the techniques of old masters
• Bathroom, kitchen: the manufacturer also recommends it for these rooms - the same filler throughout the home
• Sanding before painting: easily sanded with abrasive paper - quick, even finishing

What is it suitable for?

Substrates: Old and new plaster (cement, lime, gypsum - after curing shrinkage), gypsum and faux-marble walls, plasterboard, brick-and-gypsum panels and fibre-reinforced cement panels, precast concrete walls.

Functions: Skim coat and fine smoothing compound, plaster skim coat beneath paint or wallpaper; exposed decorative topcoat (mirror, faux marble) without paint.

Areas: Indoors — living areas, bedrooms, children’s rooms, offices, bathrooms, kitchens.

Not suitable:

• For exterior use
• Beneath potassium silicate paint or coverings — this neutralises the mangiaVOC effect
• On non-absorbent, damp, dusty or contaminated substrates
• On friable substrates without consolidation — first apply Rasobuild Eco Consolidante
• For a layer thicker than 3 mm in a single application

The mangiaVOC wall system

The mangiaVOC smoothing compounds — part of Kerakoll’s natural systems — consist of two Biogesso skim coats. Both absorb indoor formaldehyde — their purposes differ.

Rasa&Decora or Stucco?

What they have in common: mangiaVOC formaldehyde absorption; 90% less dust during mixing than conventional products; A1 fire rating; for interior use.

Which one do you need?

• Plasterboard: jointing, screw heads, skim coat beneath paint (Q1–Q3), board bonding: Biogesso Stucco
• Complete smoothing of plastered, concrete or mixed-substrate walls: Biogesso Rasa&Decora — this is the product
• Paint-free decorative wall (mirror, faux marble): Biogesso Rasa&Decora — this is the product; on plasterboard, apply Stucco to the joints first

Detailed comparison: Skim coat or drywall joint compound? - Q1-Q4 levels, material consumption and prices per m²

Frequently asked questions

Why does the skim-coated wall show stripes in raking light?
Because the skim coat sets too quickly, leaving overlaps. You need a skim coat with a long working time, applied in two coats perpendicular to each other. This allows the surface to pass the raking-light test.

What does mangiaVOC mean?
The wall absorbs formaldehyde from indoor air. Formaldehyde is the main indoor volatile organic compound (VOC). Biogesso converts it into a neutral (inert) compound (Eurofins report).

Which skim coat should I use in a bathroom or kitchen?
According to the manufacturer, Biogesso Rasa&Decora is also suitable for bathrooms and kitchens. It is an interior product - not for outdoor use.

Does the skim-coated wall need to be painted?
It is not required. Left exposed, two coats create a glossy, polished-white mirror effect. Painting or wallpapering can be done after approximately 24 hours.

What paint can be applied over it without losing the effect?
Only use breathable Kerakoll decorative finishes. Do not use potassium silicate paint or tiles. Other decorative finishes may neutralize the mangiaVOC effect.

How much skim coat do I need per m²?
≈ 1 kg/m² per millimetre. One 25 kg bag covers approximately 25 m² at 1 mm thickness. Maximum 3 mm per coat.

What is the difference between Rasa&Decora and Stucco?
Rasa&Decora smooths any plastered wall over its entire surface and creates a decorative finish without painting. Biogesso Stucco is for drywall: it fills joints, provides a covering coat beneath paint, and bonds boards. For a decorative wall on drywall, you also need Rasa&Decora. Details and prices: Skim coat or drywall joint compound?

When should I not use it?
Outdoors, or on damp or non-absorbent substrates. It is also not suitable beneath potassium silicate paint. First consolidate crumbling plaster with Rasobuild Eco Consolidante.

Can I apply it myself?
Yes, with a practiced hand for skim coating: the working time is long. However, the mirror and faux-marble effects require professional expertise. We also apply decorative finishes.