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!

How to Block Mould and Mildew Stains

Supplies

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.

Tools

Cloth

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.

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.