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Mildew treatment buying guide

Updated: 23 October 2026

You have a black patch on a ceiling, a tile, or a chair, and amazon.co.uk is mixing four jobs under one search. This mildew treatment buying guide splits a fungicidal wash, a remover, a preventer, and a fabric blocker. The [mildew treatment comparison](/hub/paints-and-varnishes/mildew-treatment) keeps three bottles and their listing prices. Here you match the surface on the label to the job in front of you. Peter F. updated this page on 23 October 2026. Prices are amazon.co.uk shelf prices unless a DIY-shed price is named as such. This is not a laboratory test. Our amazon.co.uk links may earn a commission at no extra cost to you.

You have a black patch on a ceiling, a tile, or a chair, and amazon.co.uk is mixing four jobs under one search. This mildew treatment buying guide splits a fungicidal wash, a remover, a preventer, and a fabric blocker.

Our top picks

Mold Armor Mold Armor FG516 mould blocker 946 ml

Best overall

Mold Armor Mold Armor FG516 mould blocker 946 ml
8.2/10about £25.47
View offer
Professional Strength Professional Strength bleach-free mould remover 500 ml

Best value

Professional Strength Professional Strength bleach-free mould remover 500 ml
8.0/10about £9.99
View offer
Strewth Strewth mould preventer spray 500 ml

Alternative

Strewth Strewth mould preventer spray 500 ml
6.6/10about £14.99
View offer
On this page
  1. 1.What you are buying
  2. 2.The label checks that matter
  3. 3.How the three amazon.co.uk bottles split
  4. 4.Size and money

What you are buying

A fungicidal wash is a surface biocide for hard surfaces such as plaster, brick, stone, or wood. The Health and Safety Executive treats these washes as home pesticides: the amateur bottle is the one labelled for someone without training. A retail remover is a trigger spray whose title names bathrooms, kitchens, or walls. A preventer is a leave-on liquid for tile, grout, seals, or walls after the stain has gone. A fabric blocker is for upholstery. A rose or vegetable spray belongs in the garden. Professional Strength is the remover whose title names bathrooms, kitchens, and walls. Strewth is the preventer whose listing names tile, grout, walls, and seals. Mold Armor FG516 is the spray whose surface field is fabric and whose uses are furniture and upholstery. A fabric listing does not become a wall wash because one review tried a ceiling. Application sits on how to use mildew treatment.

The label checks that matter

Read the surface line before the star rating. GOV.UK's damp and mould guidance for housing tells landlords to use a mould and mildew product rather than bleach, and to deal with the moisture as well as the colour. A bleach-free title is closer to that preference than a chlorine spray. It is not proof the liquid is mild, registered, or safe on emulsion. An HSE number is the approval reference many fungicidal washes print. None of the three amazon.co.uk scrapes shows an HSE number or a coverage figure. A blank product page is not proof either way. If you need the number, read the label. Coverage rates from other washes do not transfer to these bottles.
Mold Armor Mold Armor FG516 mould blocker 946 ml

Testsieger

Mold Armor Mold Armor FG516 mould blocker 946 ml
8.2/10about £25.47
View offer

How the three amazon.co.uk bottles split

Professional Strength is 500 ml at £9.99, about £19.98 per litre, with 4.2 from 15 reviews. All six raw texts are from the United Kingdom. One mentions little smell and says wash the mould down first. the listing's "no liquid" flag conflicts with a 500 ml spray. Who should take which bottle is on best mildew treatment. Strewth is 500 ml at £14.99, about £29.98 per litre, with 3.8 from four reviews. Bullets say spray on and leave, with no wipe. The only UK text says a wipe was needed, and that mould returned within two weeks while humidity stayed high. Mold Armor FG516 is 946 ml at £25.47, about £26.92 per litre, with 4.2 from 2,876 reviews. It is the top pick only because it is the only kept listing at 4.2 with at least 500 reviews. Of the first 50 texts, one is from the United Kingdom. Most of the sample is from the United States. Buy it for the upholstery the listing names.

Size and money

A 500 ml trigger is a patch bottle unless the label prints a generous coverage rate, and none of these three does. B&Q lists a Bartoline fungicidal wash spray at £7.99, which is £15.98 per litre on that page. That is a shed price for a named wash, not an amazon.co.uk price for Professional Strength or Strewth. Inside this set the litre order is Professional Strength at about £19.98, Mold Armor at about £26.92, and Strewth at about £29.98. If you are about to emulsion, read mildew treatment before painting after you have a wall wash, not a fabric spray.

Common questions

Do I need a fungicidal wash or a bathroom spray?
You need the label that names your surface and your job. A fungicidal wash is the hard-surface biocide before you decorate. A bathroom spray fits a small patch when the title names bathrooms, tiles, or grout. Above about a square metre, Healthy Homes says get advice.
What does an HSE number tell me?
It is the approval reference many surface biocides print. Bartoline's maker page prints HSE 9626 for its wash. A four-litre datasheet on the same site prints HSE 10392, so read the bottle rather than merging the pages. None of these three amazon.co.uk scrapes shows a number.
Is a bleach-free title enough?
It says the listing is not selling chlorine bleach. It does not state the surface, the dwell time, or an HSE number. Professional Strength names walls. Mold Armor is chlorine free and the listing surface is fabric. "Pet safe" is one Professional Strength review, not a toxicity study.
Can I use a fabric mould blocker on a painted wall?
Only if the label names paint or masonry. Mold Armor's surface field is fabric, and the uses are furniture and upholstery. The only United Kingdom review in a sample of 50 texts tried a bathroom ceiling and saw no instant change.
How big a bottle do I need for a patch?
None of these listings prints coverage, so 500 ml is not an exact wall area. Bartoline's wash, a different product, quotes about 500 ml per 2.5 square metres. Permagard's concentrate quotes about 10 to 12 square metres per litre after dilution, and that rate does not transfer.
Should I buy the preventer and the remover as two steps?
Sometimes. Furniture Clinic says clear the stain before a blocker. That could mean Professional Strength on a wall the title names, then Strewth if the label matches tile or seals. Strewth's only written review saw mould back within two weeks until the humidity dropped.

Related pages

Mildew treatment comparison

Best mildew treatment

How to use mildew treatment

Mildew treatment before painting

Bathroom mildew treatment: ceiling, grout and seals

Sources

Public sources from the research digest, last checked on 22 October 2026. Shelf prices and star lines are the amazon.co.uk figures stored on 19 October 2026. The price band is this set, not a market average. No listing was lab-tested.

  1. GOV.UK: damp and mould, health risks for rented housing (retrieved 22 October 2026)
  2. GOV.UK: Awaab’s Law guidance for tenants in social housing (retrieved 22 October 2026)
  3. The Hazards in Social Housing (Prescribed Requirements) (England) Regulations 2025 (retrieved 22 October 2026)
  4. GOV.UK: damp and mould in the private rented sector (retrieved 22 October 2026)
  5. Bartoline Fungicidal Wash (retrieved 22 October 2026)
  6. Dulux Weathershield Fungicidal Wash (retrieved 22 October 2026)
  7. Dulux Trade Paint Expert: general FAQs (retrieved 22 October 2026)
  8. Healthy Homes: damp and mould guide (retrieved 22 October 2026)