You paint a wall yellowed by the kitchen or by tobacco and, after a while, the stain comes back, brown, through the new paint. This guide explains why it happens, how to clean first, which stain-blocking primers exist (with figures from technical data sheets) and how to use the solvent-based ones safely.
Updated on 4 November 2026. General information, not a substitute for a technician’s assessment.
The essentials
- Grease, nicotine and smoke leave a film that can migrate into the new paint. Painting straight over it, even with two coats of emulsion, tends to let the stain return.
- The right order: clean and let it dry, then stain-blocking primer, then the finishing paint.
- The data sheets we read ask for 1 coat (Barbot, Dyrup) or 1 to 2 (Hempel, Akzo, CIN). For very heavy nicotine or smoke, Neuce advises 2 coats.
- Solvent and shellac blockers work very well, but they smell, ignite and need ventilation and protection. Water-based ones are easier to use.
- A water stain is a different case: it is only blocked after the leak is fixed. See painting after a leak is fixed.
Why the stain comes through the paint
Grease, nicotine and smoke stay on the wall surface. If the new paint has no barrier beneath it, the stain can show through or rise into the finish. That is why the sheets talk about “preventing stain migration” (Barbot 1003), and why Dyrup 1189 recommends its blocking primer on interior plaster and render “especially in smoky environments”.
1. Clean first
The manufacturers agree: the surface must be clean, dry and free of grease. Barbot asks for surfaces free of dust and grease. For repainting, Hempel says to wash the whole surface with a suitable detergent, remove residues with clean water and let it dry completely. Zinsser says that before blocking a stain you should first try to remove as much of it as possible by washing, sanding or scraping.
In practice:
- Protect the floor and furniture. Work from top to bottom.
- Wash with warm water and washing-up liquid or a degreaser. Use a sponge, not sandpaper.
- Wipe with clean water to remove the detergent, as Hempel asks.
- Let it dry well. Barbot requires substrate moisture below 5 % and air relative humidity below 80 %.
- Scrape off loose paint and repair cracks before priming. See skimming and filling walls.
If the smoke came from a fire, Zinsser says to remove loose soot first with a dry sponge or duster.
2. Choosing the blocking primer
| Type | Example (sheet read) | Sheet data |
|---|---|---|
| Water-based | Barbot Primário Aquoso Anti-Mancha 1003 (Feb 2015) | 1 coat undiluted, 8 to 12 m²/L, recoat after 2 h, VOC max. 10 g/L, water clean-up. Air above 5 °C. |
| Water-based, blocker and finish | Hempel’s Tixo-Mat Al Agua 58150 (Jan 2008) | 1 to 2 coats undiluted, 8.8 m²/L, touch dry in 1 h, minimum recoat 6 h at 20 °C, VOC 8 g/L. Air above 5 °C (preferably 10 °C). |
| Water-based acrylic multi-purpose | Neuce Multineuce (2006 edition) | 8 to 10 m²/L per coat. 2 coats for very heavy nicotine or smoke. |
| Alkyd (solvent) | Dyrup Primário Aparelho Isolante 1189 (Jun 2014) | 9 to 10 m²/L, touch dry about 1 h, fully dry 12 to 24 h, VOC max. 350 g/L, flash point 29 °C. Thinner clean-up. |
| Acrylic in solvent | Akzo Tixodor Plus 242 (09/2018) | 1 to 2 coats, 9 to 12 m²/L, recoat 6 h, VOC 495 g/L. Between 5 and 40 °C. |
| Thixotropic in solvent | Isaval Tixoval Antifumo 1057 (v. 3, 5 March 2025) | 4 to 6 m²/L, recoat 24 h, VOC max. 480 g/L. |
| Shellac | Zinsser B-I-N (sheet BIN-06, rev. 2015) | Touch dry 15 min, recoat 45 min, about 12.5 m²/L. VOC max. 585 g/L. |
Notes for reading the sheets:
- VOC (volatile organic compounds) values show the difference: water-based ones are below 10 g/L, solvent ones between 350 and 585. See paint, VOCs and the label.
- Tixodor Plus asks that emulsion goes on top only after 15 days, far longer than with water-based ones. Always read the recoat interval for the finish you will use.
- The Hempel sheet is from 2008 and the Neuce one from 2006. Ask the manufacturer or the shop for the current version.
- The figures are the manufacturers’ own. Isaval warns that real site conditions may vary.
3. Water-based, solvent or shellac?
Water-based first. The Barbot and Hempel sheets cover nicotine, grease and smoke, clean up with water, and Hempel says the smell is practically nil. In a lived-in home this is the most practical option.
Solvent for strong stains. Tixodor Plus lists grease, damp, rust and tobacco smoke and says one coat is enough in most cases. The price is smell, more VOCs and thinner clean-up.
Shellac as a last resort. The Zinsser sheet says one coat blocks water, mould, grease and other stains, and seals odours. It is an English-language sheet, for a brand we could not confirm on sale in Portugal. The same sheet warns that spot-primed areas can “flash” through paints with poor hiding power, such as many ceiling paints: use a high-hiding finish.
Safety with solvents
- Ventilate. Akzo says to work in well-ventilated areas and use suitable respiratory protection when needed. Hempel asks the same for its water-based product in enclosed spaces.
- Zinsser says to remove all sources of ignition. Dyrup 1189 has a flash point of 29 °C. No flames, no smoking, no gas heater or element nearby.
- Houses built before 1960 may have lead paint. Zinsser warns to take care when sanding. See old paint, lead and sanding safety.
4. Apply and paint
- Respect the sheet’s conditions. Examples: Barbot, above 5 °C and relative humidity below 80 %. Akzo, between 5 and 40 °C and up to 85 %. Zinsser, relative humidity below 85 %.
- Stir well. Do not thin unless the sheet says so.
- Brush the corners and roll the rest. Block the stain and a margin around it, and paint the whole wall from corner to corner, because painting only the patch usually leaves a difference in tone (common practice, not in the sheets). See painting ceilings: technique and stains.
- Wait for the recoat interval on the sheet.
- Finish with a good-hiding paint. For quantities use the calculator. On the sheets, primer covers between 4 and 12 m²/L depending on the product.
- If the stain still shows, do not paint over it again: let it dry, block it again and repaint. See peeling paint and stains.
When it is not grease or smoke
- Water stain (brown outline, with rings): the cause is a leak or seepage. Stop the source, dry, and only then block. The CIN Stop Manchas sheet, cited in our ceiling guide, speaks of dry stains.
- Mould (black or green spots): a primer does not fix the cause. See mould on walls. The Isaval sheet says to disinfect the area with a brush and household bleach or 10-volume hydrogen peroxide before painting, but the cause of the damp must be dealt with.
- Smell: a shellac blocker seals odour, according to its maker. The water-based sheets we read make no such promise.
What we could not confirm
- Which product is best. We found no independent test comparing these primers. The data are the manufacturers’.
- How long the barrier lasts in years. The sheets do not say.
- Whether Zinsser B-I-N is sold in Portugal and whether a Portuguese sheet exists. We read the English version.
- An official cleaning method for nicotine. We found only the principle in the sheets (detergent, rinse, dry). Internet recipes with ammonia, vinegar or phosphates were not checked by us.
- Prices of the primers: we do not give any.
Sources (read on 4 November 2026)
- Barbot, Primário Aquoso Anti-Mancha, ref. 1003, data sheet, February 2015 (use, coverage, conditions, VOC).
- Hempel, Hempel’s Tixo-Mat Al Agua 58150, technical information, January 2008 edition (preparation, coats, intervals).
- Neuce, A2 Multineuce, water-based multi-purpose acrylic primer, edition no. 1, 16 October 2006.
- Dyrup, Primário Aparelho Isolante, ref. 1189, technical/commercial information, June 2014.
- Akzo Nobel, Tixodor Plus, code 242, data sheet, edition 09/2018.
- Isaval, Tixoval Antifumo, ref. 1057, version 3, 5 March 2025.
- Zinsser, B-I-N Shellac-Based Primer-Sealer Stain Blocker, sheet BIN-06, rev. 051515, in English.
- CIN, Primário Stop Manchas 45-335 (July 2013), cited through our guide painting ceilings, not re-read today.