How to block mould and mildew stains permanently with Zinsser

Mould and mildew are horrendous. Not only does it look bad, but it can also badly affect your family’s health, particularly if they have breathing difficulties. In this guide we show you how to block mould and mildew stains permanently with Zinsser. Follow these simple steps and you can’t go wrong!

What is Mould and Mildew and why Does it Grow?

Mould and mildew are both forms of fungus that grow in warm, wet conditions. They’re common in places like bathrooms, shower rooms, and kitchens. It looks unsightly, but that isn’t the only issue; black mould can cause health problems, particularly if you have allergies or asthma.

We’re going to talk about how to block mould and mildew stains permanently in a moment, but it’s good to understand why the stains are there in the first place.

Mould and mildew tend to grow in rooms where water condenses on a surface. Water is most likely to condense on the coldest wall in a room, so that’s often where the problem is worst.

A lack of ventilation can be one of the leading causes of mould and mildew growth. That’s why you see extraction fans in bathrooms, and you often see mould behind wardrobes and other furniture.

One of the other things that can encourage mould and mildew growth is the use of the wrong type of paint. I’m not just talking about the lack of anti-mould paints like Zinsser Perma White, but some people use cheap contract matt emulsion on their interior walls and ceilings.

This type of paint doesn’t contain much polymer binder and remains porous. That means it absorbs water and takes longer to dry out. Moreover, the powdery paint acts as a medium for the fungus to grow.

How to Block Mould and Mildew Stains

Let’s get into the meat of the blog. I’m going to start by listing the tools and materials you need to block mould and mildew stains, I’ll link to the best place to buy each product, and then I’ll take you through the steps.

I’m a Painter and Decorator, so I can talk about how to deal with mould and mildew from a decorating standpoint; not just so it’s covered, but so it doesn’t come back. However, you may also need to consider insulation on a particularly cold wall, and ventilation in a room.

I’ll go into little bit more depth about each of the hero products after taking you through the steps.

Zinsser Mould Killer – Click here to see online prices.

Zinsser Universal Cleaner & Degreaser – Click here to see online prices.

Zinsser BIN Primer Sealer – Click here to see online prices.

Perma-White Interior – Click here to see online prices.

Paintbrush – Click here to see online prices.

Roller – Click here to see online prices.

 Steps

Surface Preparation

All surfaces must be clean, dry and free from anything that will interfere with the adhesion of the materials to be applied. Remove loose and failing material by scraping or brushing with a stiff bristle brush to a sound edge. Feather sound edges with a fine grade abrasive paper. Remove all visible signs of organic growth and treat the areas with Zinsser Mould Killer in accordance with the manufacturer’s instructions. Allow to dry.

In areas with remaining sound paint, clean down with Zinsser Universal Cleaner & Degreaser to remove any contaminants. Rinse thoroughly with clean water to remove all residues. Allow to dry.

Fill any cracks and small surface defects with a suitable filler as appropriate in accordance with the manufacturer’s instructions. Allow to dry. Rub down with a fine grade abrasive paper. Remove all dust.

I know it’s a cliché but prep really is the most important part of the job, particularly when blocking mould and mildew stains. If you do not kill the mould, then it will simply come back or spread.

Some people use diluted bleach to try and kill the mould, but this can make the issue worse. It kills the surface mould but doesn’t affect the membrane underneath. Mould will often come back, even if you follow all the other steps correctly. A specialist mould treatment like Zinsser Mould Killer is much better.

Priming

Prime all stained, bare and filled areas with one coat of Zinsser BIN Primer Sealer in accordance with the manufacturer’s instructions. Allow a minimum drying time of 45 minutes in normal drying conditions. Zinsser BIN does a couple of things; it aids adhesion to difficult and bare surfaces. It also blocks stains, which often occur when mould and mildew is present.

Decoration

Decorate with two full coats of Perma-White® Interior Matt, Satin or Semi-Gloss in accordance with the manufacturer’s instructions. Allow a minimum drying time of two hours between coats. Zinsser Perma White contains a biocide which inhibits the growth of mould moving forward.

The Best Products to Treat and Cover Mould and Mildew

FAQs

What is the easiest way to get rid of mould?

The easiest way to get rid of mould is to treat the area, block the stain, and then use anti-mould paint. You may need to look into whether there is a bigger underlying issue causing mould growth, such as lack of ventilation or excessive condensation.

What kills 100% of mould?

Some people claim white vinegar and baking soda works on mould, and they do to a point, but not properly. Other people use bleach, which can make mould and mildew spread. Our advice is to use a specialist mould treatment like Zinsser Mould Killer.

Can I get rid of mould by myself?

Absolutely, you don’t need to be a professional to get rid of mould unless there is a substantial underlying problem. Most of the time, it’s just about treating the mould and then using the proper paint products to redecorate.

Will opening windows reduce mould?

Opening widows will increase airflow and allow moist air to escape, resulting in less condensation and less mould growth in your room. This can be a great temporary solution, but you will need to address the issue properly at some point.

What is the best mould remover?

The best mould treatment on the market is probably Zinsser Mould Killer. Specialist products like this are far more effective than household cleaners.

Final Thoughts

I hope this has helped. Mold and mildew can be an absolute nightmare, and sometimes painting alone is not enough to solve the issue over a prolonged period. You should also try to ventilate the room or even insulate to reduce the amount of condensation.

That said, a proper paint system like Zinsser and carrying out the correct steps will give you a fighting chance.