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Zinsser B-I-N vs Cover Stain

Updated: October 2026

You are looking at two white Zinsser tins and trying to decide which one is the stronger stain block. Zinsser B-I-N vs Cover Stain is not a single ranking. B-I-N is a shellac primer for interior stains, odours, and knots, with outdoor use limited to spots. Cover Stain is an oil primer for a full interior or exterior prime, and its own sheet tells you to spot knots with B-I-N first. This page uses only the packs in this set: B-I-N 5 litres at £96.95, Cover Stain 1 litre at £17.48, and Cover Stain 5 litres at £59.93. Johnstone's, Bartoline, and Polar stay on the [stain block primer comparison](/hub/paints-and-varnishes/stain-block-primer). The Products Compared editorial team used these amazon.co.uk listings and Zinsser UK sheets on 16 October 2026. No laboratory test was run. A qualifying purchase can earn a commission at no extra cost to you.

You are looking at two white Zinsser tins and trying to decide which one is the stronger stain block. Zinsser B-I-N vs Cover Stain is not a single ranking.

Our top picks

Zinsser Zinsser Cover Stain 5 litre

Best overall

Zinsser Zinsser Cover Stain 5 litre
8.4/10about £59.93
View offer
Zinsser Zinsser Cover Stain 1 litre

Rank 2

Zinsser Zinsser Cover Stain 1 litre
9.4/10about £17.48
View offer
Zinsser Zinsser B-I-N 5 litre

Alternative

Zinsser Zinsser B-I-N 5 litre
8.3/10about £96.95
View offer
On this page
  1. 1.B-I-N and Cover Stain are different binders
  2. 2.Indoors, odours, and knots versus a full prime
  3. 3.Knots: shellac on the spot, then Cover Stain on the board
  4. 4.Smell, dry time, coverage, and which tin in this set
  5. 5.Which tin to buy

B-I-N and Cover Stain are different binders

B-I-N, ASIN B003AIFRMA, is sold as a shellac-based primer-sealer. The amazon bullets describe odours, knots, smoke, and varnished wood. The paint-type attribute says enamel, which conflicts with those bullets, so trust the shellac description on Zinsser’s own page rather than that one attribute. The UK product page gives about 15 minutes touch dry, about 45 minutes to recoat, and 12.5 m² per litre. Cover Stain is the oil, or alkyd, primer. UK reviews call it a solvent sealer and mention white spirit. The 1 litre listing, ASIN B00A497ATG, states 9.8 m² per litre. The 5 litre paint-type field only says PAINT.

Indoors, odours, and knots versus a full prime

Buy B-I-N when the job is inside the house and the problem is smell, smoke, or a knot. The bullets claim it seals knots and sap streaks and blocks odour. The title says interior and spot exterior. Do not prime a whole outside wall with it. Buy Cover Stain when you need that stain blocking as a full prime on interior or exterior wood, masonry, or metal, and you can ventilate.
Zinsser Zinsser Cover Stain 5 litre

Testsieger

Zinsser Zinsser Cover Stain 5 litre
8.4/10about £59.93
View offer

Knots: shellac on the spot, then Cover Stain on the board

The practical shape of that job is small. You do not need 5 litres of shellac to spot three knots on a pine door. This set only stocks B-I-N in 5 litres at £96.95, about £19 per litre. This comparison does not include a smaller B-I-N tin, so do not borrow another pack price. After the spots are dry, prime the board with Cover Stain.

Smell, dry time, coverage, and which tin in this set

SI 2012/1715 caps a solvent-borne primer at 350 g/l, and Cover Stain’s 335 g/l sits under that cap. Coverage, where the page states it, favours the shellac tin on paper: 12.5 m² per litre against 9.8 m² per litre for Cover Stain. The 5 litre Cover Stain listing does not state coverage. Its attribute is the bare number 5. For a dry water stain that is only a ceiling ring, the water stains page is the closer brief.

Which tin to buy

Choose B-I-N if the work is interior smoke, pet odour, or knots, and if a 5 litre shellac tin is a volume you will use. Choose Cover Stain if you need a full prime indoors or outdoors and the room or the elevation can be ventilated, with white spirit to hand. Skip Cover Stain for a closed bedroom. If the stain is a modest dry mark and you would rather have a water-based claim, leave this pair and use the buying guide. Coat order once the tin is chosen is in how to use stain block primer.

Common questions

Is Zinsser B-I-N better than Cover Stain?
B-I-N is the better fit for interior odour and knots. Cover Stain is the better fit for a full interior or exterior prime if you can accept white spirit and a strong smell. Use shellac for indoor smell and for spots, oil for a whole prime, and shellac spots under oil when the timber has knots.
Which one blocks nicotine, smoke, and pet odour indoors?
Both are sold against smoke. B-I-N’s claim is the closer match for pet smell, if a 5 litre tin is realistic. Cover Stain’s UK page lists nicotine and smoke, and 5 litre reviews mention those stains, with a stronger solvent smell. Start with B-I-N for smell. Use Cover Stain when you also need to prime a room you can air.
Can I use B-I-N on an outside wall?
Only as a spot primer. Zinsser does not sell B-I-N as a whole-wall exterior system. Cover Stain is the tin in this pair for interior and exterior wood, metal, and masonry. The 1 litre listing still conflicts, with an indoor attribute beside interior-and-exterior bullets. Follow the title and the data sheet, not the tick-box.
Do knots need B-I-N even if I buy Cover Stain?
Yes, if you follow Cover Stain’s sheet. Spot-prime knots and sap streaks with B-I-N, then prime the board with Cover Stain, and wait at least 2 hours on resinous timber. The oil tin does not replace that spot. This set only has B-I-N in 5 litres, which may be more than one door needs.
How do smell and brush clean-up differ?
Cover Stain reviews describe a strong smell that can last a day or two, and brushes need white spirit. B-I-N recoats in about 45 minutes and cleans with denatured alcohol or ammonia. Ventilate both. Do not pile solvent rags, and do not treat the shellac tin as odourless.
Is 5 litres of B-I-N better value per litre than 5 litres of Cover Stain?
No. B-I-N is £96.95, about £19 per litre. Cover Stain is £59.93, about £12 per litre. The extra buys shellac for odour or knots, not cheaper coverage. Stated rates are 12.5 m² per litre for B-I-N and 9.8 m² per litre for Cover Stain. The 5 litre Cover Stain page does not print that 9.8 figure.
Will either tin fix a wet ceiling?
No. Both need a hard, dry surface. A soft or dripping ceiling is a leak, and paint hides the evidence. The 12% moisture figure applies after the water has gone. If a finger test fails, call a leak specialist before you pick a binder.

Related pages

Best stain blocking paint UK

Stain block primer

Stain block primer buying guide: match stain, room

How to use stain block primer once the board is dry

Paint over water stains on a ceiling after the leak

Sources

Public UK sources for the primer rules, ventilation and manufacturer figures on this page. Prices, stars and review counts are the amazon.co.uk listing lines in this batch.

  1. SI 2012/1715 — VOC in paints and varnishes (retrieved 17 October 2026)
  2. HSE INDG273 — Solvents and ventilation (retrieved 17 October 2026)
  3. Zinsser UK — B-I-N (retrieved 17 October 2026)
  4. Zinsser UK — Cover Stain (retrieved 17 October 2026)
  5. Zinsser UK — Water-stained surfaces (retrieved 17 October 2026)
  6. Checkatrade — Water leaking from a ceiling (retrieved 17 October 2026)
  7. Johnstone’s 750 ml retailer notes (retrieved 17 October 2026)
  8. B&Q — Bartoline stain blocker spray directions (retrieved 17 October 2026)