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How To Paint Exterior Water Stains

Successfully block exterior water stains and permanently prevent mould and mildew from seeping through newly painted surfaces – our 4-step guide below walks you through on how to suitably prepare and prime before painting over water stains with Zinsser products, featuring a decorative topcoat that is available in more than 350 colours.

If your gutter is the cause of the water staining, see our blog post on how to repair guttering.

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Zinsser Paint Exterior Water Stains Products

The Benefits

Step 1. Surface Preparation

Step 2. Priming

Step 3. Water Stains

Step 4. Decoration

More Information

Further Reading


Zinsser Paint Exterior Water Stains Products

Zinsser Mould Killer & Remover

Zinsser Cover Stain

Zinsser AllCoat Exterior Satin/Gloss

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The Benefits

Water stains can appear on exterior surfaces such as:

  • Walls
  • Cladding
  • Around guttering
  • Under soffits
  • Around signage
  • Above doorways, porches and entrances

Water stains on building exteriors look dirty and really harm the attractiveness of premises and the reputation of a business. How many times have you, as a customer, walked or pulled up to a stained building and decided to go elsewhere, without even stepping inside?

First impressions are everything, and in a crowded marketplace on the high street it pays off to have a clean and tidy store.

For landlords, potential tenants will likely think twice before booking an appointment to view your vacant property, leaving you without a rental income for longer. Even those that do view could use water-stained exteriors as a reason for negotiating a reduced rate.

Zinsser listens to contactors and develops new products – or adds features to existing products – to meet their changing needs, delivering world class products that meet “real world” challenges, providing tried and tested solutions to painting problems, such as painting over exterior water stains.

How to stop water stains from bleeding through paint? Zinsser Cover Stain is an unrivalled primer, sealer and stain blocker for interior and exterior surfaces, drying in just 2 hours. Overcoating with their exterior Allcoat paint allows problem areas to be covered in more than 350 colours

Step 1. Surface Preparation

The exterior surface must be clean and dry and free from anything that will interfere with or affect the adhesion of the materials and Zinsser coatings to be applied.

Remove loose and failing material through scraping or brushing with a stiff bristle brush to a sound edge, feathering with a fine grade abrasive paper and removing all dust.

Prior to painting, the moisture content should not exceed 18%.

All visible signs of organic growth should be removed, treating the affected areas with Zinsser Mould Killer & Remover, in accordance with the manufacturer’s instructions, and allow to dry.

Step 2. Priming

Wash the surface down with hot water and a liquid detergent solution to remove any contaminants, frequently changing the water, then rinse thoroughly with clean water to remove all residues and allow it to dry.

Any cracks and small surface defects should be filled with a suitable filler (in accordance with the manufacturer’s instructions) and allowed to dry before rubbing the affected areas down with a fine grade abrasive paper and removing all dust.

Patch prime all bare and filled areas with one coat of Zinsser Cover Stain in accordance with the manufacturer’s instructions, allowing a minimum of 2 hours drying time( in normal drying conditions), bringing forward patch primed areas with one further coat of Zinsser Cover Stain, and allow to dry.

Step 3. Water Stains

Prime all previously water stained areas with one full coat of Zinsser Cover Stain and allow a minimum drying time of 2 hours, in normal drying conditions, before moving on to decorating.

Step 4. Decoration

Decorate the fully prepared and primed surface with two full coats of Zinsser AllCoat Exterior Satin/Gloss in accordance with the manufacturer’s instructions, allowing a minimum drying time of one hour between coats.

More Information

If you require more advice on painting over exterior water stains, give our technical team a call on 0113 2455450 (option 2) or send a message to [email protected].

Further Reading

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